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Komodo CAN Interface User Manual |
1 General Overview
1.1 CAN Background
1.1.1 CAN History
CAN (Controller Area Network) is a serial bus protocol created in the mid-1980s by the German company Bosch. It is optimized for sending small amounts of data between multiple nodes. CAN is not a fast bus by today's standards, with a maximum data rate of only 1 Megabit per second. However, operating at low data rates makes CAN quite robust to noise and allows buses to span long distances.
CAN was originally designed for use in automobiles, but has also become popular in low-bandwidth industrial applications such as controlling assembly line machines.
Although Boschs CAN specification does not define standard CAN voltages or connector interfaces, standards organizations have defined multiple physical standards. The most common CAN physical layer standard is ISO 11898-1, but others are also used.
1.1.2 CAN Theory of Operation
CAN allows multiple devices (referred to as "nodes") to connect to each other on a single bus, as shown in Figure 1. Unlike other protocols, such as I2C and SPI, CAN nodes do not have strict master/slave roles. Instead, each CAN node may operate as a transmitter or receiver at any time.
Rather than sending data to specific targets, data messages are broadcast to all nodes on the bus. Each receiver node decides for itself if the data is relevant by looking at the message frame's "identifier," which describes the content of the message. A message's identifier also represents the priority and allows for automatic arbitration when multiple nodes try to transmit at the same time.
A CAN bus can have two bit states: dominant or recessive. If one node sends a dominant bit and another sends a recessive bit, the result will be dominant (as shown in Table 1). Automatic arbitration is built in to the CAN protocol as all nodes must monitor the bus state during transmission and cease transmission if a dominant bit is seen when sending a recessive bit.
| Dominant | Recessive | |
| Dominant | Dominant | Dominant |
| Recessive | Dominant | Recessive |
The CAN protocol specifies four fundamental frame types which nodes use to interact:
- Data Frame – carries 0-8 bytes of data, along with an identifier and CRC check
- Remote Frame – requests a data frame transmission with a certain identifier node
- Error Frame – transmitted when an error is detected
- Overload Frame – provides extra delay between data and remote frames
For more details on message frame formatting, please consult Boschs CAN specification 2.0 and the other resources listed in Section 1.1.5.
Further physical layer details are undefined by CAN specification "so as to allow transmission medium and signal level implementations to be optimized for their application." Common physical layer implementations, such as the ISO 11898, use a balanced differential CAN bus. For more information about the Komodo interfaces compatibilities, please refer to Section 2.
1.1.3 CAN Features and Benefits
CAN has many important features and benefits, including:
- Multi-master – All nodes can transmit and receive messages.
- Automatic prioritization of messages – Based on message identifier.
- Automatic arbitration – Based on message identifier.
- High reliability – Achieved through built-in error checking.
- Robust – High performance, even in difficult electrical environments.
- Configuration flexibility – Nodes can be added to and removed from the bus without modifying other nodes.
- Many nodes can be connected on the same bus – CAN 2.0B defines identifiers as 29 bits, providing over 500,000 unique codes.
- Buses can be very long – On the order of miles and kilometers.
- Low cost
1.1.4 CAN Drawbacks
Here are a few drawbacks when using CAN:
- Low-bandwidth – CAN supports a maximum data rate of 1 Mbps. This is not good for high-bandwidth applications.
- Small data transfers – data frames can only carry 8 bytes, so CAN is not good for large data transfers.
- Protocol overhead – The CAN protocol has a moderate amount of overhead (strict message formatting, CRC checking, bit-stuffing, etc.) and is more complicated than other protocols such as I2C and SPI.
CAN is well-suited for connecting many devices that have small amounts of data to share with each other at low data rates. Applications other than this, such as reading from a large memory device, would not use CAN.
1.1.5 CAN References
- CAN Specification 2.0 – osch
- Controller Area Network Wikipedia article – Wikipedia
- Good introduction to CAN – Staffan Nilsson
2 Hardware Specifications
2.1 Connector Specification
The Komodo CAN Interfaces feature a connector for each CAN channel: a common DB-9 connector and a block screw terminal which wires can easily connect to.
2.1.1 D-Sub Connector
The DB-9 connector of Figure 2 follows the SAE J1939 CAN-CIA standard and has the following pinout:
- No Connect
- CAN-
- GND
- No Connect
- SHLD
- GND
- CAN+
- No Connect
- V+
Please see Section 2.3 for descriptions of the CAN signals.
2.1.2 Terminal Block Connector
Each CAN channel features a green terminal block that consists of two parts: a right-angle closed-end header and a right-angle plug. The plug includes screw terminals so it can be used easily with wires.
The terminal block pinout is as follows:
- GND
- CAN-
- SHLD
- CAN+
- V+
The terminal block pins are labeled on the top of the Komodo. Please see Section 2.3 for descriptions of the CAN signals.
2.1.3 GPIO Connector
The Komodo interface features a DIN-9 connector for GPIO use. Please see the API section of this document for more information on how to configure and use these pins.
Even though the GPIO DIN-9 cable included with the Komodo interface is labled with 4 inputs and 4 outputs, each GPIO pin can be configured as an input or an ouput. Table 2 shows the pinout for the DIN-9 connector on the Komodo interface along with corresponding color and label on the cable.
| Number | Color | Label |
| Pin 1 | Brown | IN 1 |
| Pin 2 | Red | IN 2 |
| Pin 3 | Orange | IN 3 |
| Pin 4 | Yellow | IN 4 |
| Pin 5 | Green | OUT 1 |
| Pin 6 | Blue | OUT 2 |
| Pin 7 | Purple | OUT 3 |
| Pin 8 | Grey | OUT 4 |
| Pin 9 | Black | GND |
2.1.4 USB Connector
One side of the Komodo CAN Interfaces features a single USB-B receptacle. This port connects to the analysis computer that runs the software or a custom application. This port must be plugged in to provide power to the Komodo CAN Interface and to power the CAN bus over V+ (if enabled).
2.2 GPIO
Digital inputs allow users to synchronize external logic with a CAN channel. Whenever the state of an enabled digital input changes, an event will be sent to the analysis PC.
Digital outputs allow users to output events to external devices. These pins can be set to activate on various conditions that are described more thoroughly in Section 5. A common use for this feature is to trigger an oscilloscope or logic analyzer to capture data.
Note that the GPIO's ground is the same as the USB's ground, and is isolated from each of the CAN grounds.
2.2.1 GPIO Configuration
GPIO pins can be individually configured as either inputs or outputs. Input pins can be configured to have a pull-up, pull-down, or no resistor enabled. The internal pull-up resistors have a nominal value of 1.5 k.
Output pins may be configured as active high, active low, open-drain, or open-drain with internal pull-up.
Please see Section 5 for more information on the API.
2.2.2 GPIO Signaling
The GPIO pins have a logical high output of 3.3 V. When configured as inputs, the GPIOs can withstand a maximum input of 5.5 V. Exceeding this will damage the device. Additional GPIO pin specifications are listed in Table 3.
| Input | Output | |
| V_L_MAX | 1.0 V | 0.4 V |
| V_H_MIN | 2.3 V | 2.9 V |
2.3 CAN Signal Descriptions
This section describes the function of the Komodo interface's signals. For connector pinout information, please see Section 2.1.1.
2.3.1 GND
Ground – The ground of the CAN channels are galvanically isolated from each other and the Komodo interface's circuitry. Each channel's CAN- and CAN+ signals are referenced to their respective ground pin. If a channel's ground is not connected, the signaling is entirely unpredictable and communication will likely be corrupted. Two pins on the DB-9 are connected to ground to provide a solid ground path, though it is only necessary to connect to one of these.
2.3.2 CAN-
Dominant Low – When a dominant bit is transmitted, the voltage of this pin is lower than CAN+. When configured as an input, voltage may range from -12 V to 12 V. See Section 2.5.1 for more details.
2.3.3 CAN+
Dominant High – When a dominant bit is transmitted, the voltage of this pin is higher than CAN-. When configured as an input, Voltage may range from -12 V to 12 V. See Section 2.5.1 for more details.
2.3.4 V+
Power – The Komodo interfaces can optionally source power to the CAN bus. If enabled, the Komodo CAN Interfaces will provide approximately 4.8 V out on this pin and can source up to 73mA (per CAN channel). The Komodo will illuminate the CAN power LED if power is detected on this pin.
The input voltage on V+ should not exceed 30 V.
2.3.5 SHLD
CAN Shield – This pin may optionally be connected to the CAN bus shield.
2.3.6 No Connect
No Connect – Reserved for future use. Internally, these pins are floating.
2.3.7 Powering Downstream Devices
It is possible to power one or more downstream CAN nodes using the V+ pin. The Komodo CAN Interfaces can source a maximum of 73 mA per CAN channel with V+.
This current comes from the analysis PC's {{vbus}. See Section 2.7 for more details.
2.4 LED Indicators
The Komodo CAN Duo Interface has five LEDs in total and the Komodo CAN Solo Interface has three. The green LED labeled "USB" serves as a global power indicator. It illuminates when the Komodo interface is correctly connected to an analysis computer and is receiving power over USB.
Each CAN interface features two LEDs: an activity LED and a bi-color power LED. The bi-color power LEDs illuminate white when the Komodo interface is sourcing V+ to the CAN bus, and illuminate blue when the CAN bus is powered externally. The power LEDs will be off if power is neither observed nor sourced.
The CAN activity LEDs are orange, and their blink rate is proportional to the amount of CAN data transmitted on the bus. If no data is being sent on an active CAN channel, the activity LED will simply remain on without blinking.
2.5 Signal Levels/Voltage Ratings
2.5.1 Logic Levels
The Komodo interface signal specifications for transmitted dominant and recessive states are listed in Tables 4 and 5, respectively.
Monitored CAN signals may range from -12V to 12V.
These signal levels apply to both transmitter and monitor modes.
| Signal | Minimum V | Nominal V | Maximum V |
| CAN+ | 2.9 | 3.5 | 4.5 |
| CAN- | 0.8 | 1.2 | 1.5 |
| Differential | 1.4 | 3.0 |
| Signal | Minimum V | Nominal V | Maximum V |
| Both CAN lines | 2 | 2.3 | 3.0 |
| Differential | -0.5 | 0.05 |
2.5.2 ESD protection
The Komodo interface has built-in electrostatic discharge protection to prevent damage to the unit from high voltage static electricity.
2.5.3 Input Current
The Komodo interface may draw up to 4 mA on the CAN+ and CAN- lines when operating as a receiver.
2.5.4 Drive Current
The Komodo interface can drive all output signals with a maximum of 73 mA current source or sink. Drawing more than this may damage the hardware.
2.5.5 Capacitance
The Komodo interface may add up to 23 pF capacitance on the CAN+ and CAN- lines.
2.6 CAN Signaling Characteristics
2.6.1 Speed
The Komodo interface may operate at a maximum bitrate of 1 Mbps. Not all bitrates are supported. When an attempt is made to set the bitrate, the Komodo interface will be set to the closest supported value less than or equal to the requested value.
2.7 Komodo Device Power Consumption
The Komodo interface consumes less than 150 mA from the host PC and reports itself as a high-powered device. The Komodo interface should be plugged directly into the host PC's USB host port or a self-powered hub. The Komodo interface should not be connected to a bus-powered hub because these are only specified to supply 100 mA per port.
Using the Komodo interface to supply power to CAN nodes will draw extra current from VBUS.
2.8 USB 2.0
The Komodo interface is a full-speed USB 2.0 device.
2.9 Temperature Specifications
The Komodo CAN Interfaces are industrial grade products, rated for operating temperatures from -40 to 85°C. Any use of the Komodo interfaces outside the industrial grade temperature specification will void the hardware warranty.
3 Software
3.1 Compatibility
3.1.1 Overview
The Komodo software is offered as a 32-bit or 64-bit Dynamic Linked Library (or shared object). The specific compatibility for each operating system is discussed below. Be sure the device driver has been installed before plugging in the Komodo interface.
3.1.2 Windows Compatibility
The Komodo software is compatible with Windows XP (SP2 or later, 32-bit and 64-bit), Windows Vista (32-bit and 64-bit), and Windows 7 (32-bit and 64-bit). Windows 2000 and legacy 16-bit Windows 95/98/ME operating systems are not supported.
3.1.3 Linux Compatibility
The Komodo software is compatible with all standard 32-bit and 64-bit distributions of Linux with kernel 2.6 and integrated USB support. When using the 32-bit library on a 64-bit distribution, the appropriate 32-bit system libraries are also required.
3.1.4 Mac OS X Compatibility
The Komodo software is compatible with Intel versions of Mac OS X 10.5 Leopard, 10.6 Snow Leopard, 10.7 Lion, 10.8 Mountain Lion, and 10.9 Mavericks. Installation of the latest available update is recommended.
3.2 Windows USB Driver
3.2.1 Driver Installation
To install the appropriate USB communication driver under Windows, use the Total Phase USB Driver Installer before plugging in any device. The driver installer can be found either on the CD-ROM (use the HTML based guide that is opened when the CD is first loaded to locate the Windows installer), or in the Downloads section of the Komodo interface product page on the Total Phase website.
After the driver has been installed, plugging in a Komodo interface for the first time will cause the interface to be installed and associated with the correct driver. The following steps describe the feedback the user should receive from Windows after a Komodo interface is plugged into a system for the first time:
Windows XP:
- The Found New Hardware notification bubble will pop up from the system tray and state that the "Total Phase Komodo CAN Duo Interface" or "Total Phase Komodo CAN Solo Interface" has been detected.
- When the installation is complete, the Found New Hardware notification bubble will again pop up and state that "your new hardware is installed and ready to use."
To confirm that the device was correctly installed, check that the device appears in the "Device Manager". To navigate to the "Device Manager" in Windows XP, select "Control Panel | System Properties | Hardware | Device Manager". The Komodo interface should appear under the "Universal Serial Bus Controllers" section.
Windows Vista/7:
- A notification bubble will pop up from the system tray and state that Windows is "installing device driver software."
- When the installation is complete, the notification bubble will again pop up and state that the "device driver software installed successfully."
To confirm that the device was correctly installed, check that the device appears in the "Device Manager." To navigate to the "Device Manager" screen in Windows Vista/7, select "Control Panel | Hardware and Sound | Device Manager". The Komodo interface should appear under the "Universal Serial Bus Controllers" section.
3.2.2 Driver Removal
The USB communication driver can be removed from the operating system by using the Windows program removal utility. Instructions for using this utility can be found below. Alternatively, the Uninstall option found in the driver installer can also be used to remove the driver from the system. It is critical that all Total Phase devices have been disconnected from your system before removing the USB drivers.
Windows XP:
- Select "Control Panel | Add or Remove Programs"
- Select "Total Phase USB Driver" and select "Change/Remove"
- Follow the instructions in the uninstaller
Windows Vista/7:
- Select "Control Panel | Uninstall a program"
- Right-click on "Total Phase USB Driver" and select "Uninstall/Change"
- Follow the instructions in the uninstaller
3.3 Linux USB Driver
As of version 1.22, the Komodo communications layer under Linux no longer requires a specific kernel mode or user mode driver to operate. This differs from previous versions that required the user to ensure independently that the libusb library was installed on the system. See the README.txt in the API package for more details.
Most modern Linux distributions use the udev subsystem to help manipulate the permissions of various system devices. This is the preferred way to support access to the Komodo interface such that the device is accessible by all of the users on the system upon device plug-in.
For legacy systems, there are two different ways to access the Komodo interface: through USB hotplug or by mounting the entire USB filesystem as world writable. Both require that /proc/bus/usb is mounted on the system, which is the case on most standard distributions.
3.3.1 UDEV
Support for udev requires a single configuration file that is available on the software CD, and also listed on the Total Phase website for download. This file is 99-totalphase.rules. Please follow the following steps to enable the appropriate permissions for the Komodo interface.
- As superuser, unpack 99-totalphase.rules to /etc/udev/rules.d
- chmod 644 /etc/udev/rules.d/99-totalphase.rules
- Unplug and replug your Komodo interface(s)
3.3.2 USB Hotplug
USB hotplug requires two configuration files which are available on the software CD, and also listed on the Total Phase website for download. These files are: komodo and komodo.usermap. Please follow the following steps to enable hotplugging.
- As superuser, unpack komodo and komodo.usermap to /etc/hotplug/usb
- chmod 755 /etc/hotplug/usb/komodo
- chmod 644 /etc/hotplug/usb/komodo.usermap
- Unplug and replug your Komodo interface(s)
- Set the environment variable USB_DEVFS_PATH to /proc/bus/usb
3.3.3 World-Writable USB Filesystem
Finally, here is a last-ditch method for configuring your Linux system in the event that your distribution does not have udev or hotplug capabilities. The following procedure is not necessary if you were able to exercise the steps in the previous subsections.
Often, the /proc/bus/usb directory is mounted with read-write permissions for root and read-only permissions for all other users. If an non-privileged user wishes to use the Komodo interface and software, one must ensure that /proc/bus/usb is mounted with read-write permissions for all users. The following steps can help setup the correct permissions. Please note that these steps will make the entire USB filesystem world writable.
- Check the current permissions by executing the following command:
ls -al /proc/bus/usb/001 - If the contents of that directory are only writable by root, proceed with the remaining steps outlined below.
-
Add the following line to the /etc/fstab file:
none /proc/bus/usb usbfs defaults,devmode=0666 0 0
- Unmount the /proc/bus/usb directory using "umount"
- Remount the /proc/bus/usb directory using "mount"
- Repeat step 1. Now the contents of that directory should be writable by all users.
- Set the environment variable USB_DEVFS_PATH to /proc/bus/usb
3.4 Mac OS X USB Driver
The Komodo communications layer under Mac OS X does not require a specific kernel driver to operate. Both Mac OS X 10.5 Leopard and 10.6 Snow Leopard are supported. It is typically necessary to ensure that the user running the software is currently logged into the desktop. No further user configuration should be necessary.
3.5 USB Port Assignment
The Komodo CAN Duo Interface consists of two independent CAN channels and presents two ports to the computer when connected. The Komodo CAN Solo Interface consists of one CAN channel and presents one port to the computer when connected. For example, one connected Komodo CAN Duo Interface would be assigned ports 0 and 1, and a second Komodo CAN Solo Interface would be assigned port 2.
Note that with the Windows operating system, each Komodo interface will appear as two USB devices in the device manager.
If a Komodo interface is subsequently removed from the system, the remaining interfaces shift their port numbers accordingly. With n Komodo interfaces attached, the allocated ports will be numbered from 0 to 2n-1.
3.5.1 Detecting Ports
To determine the ports to which the Komodo interfaces have been assigned, use the km_find_devices function as described in the API documentation.
3.6 Komodo Dynamically Linked Library
3.6.1 DLL Philosophy
The Komodo DLL provides a robust approach to allow present-day Komodo-enabled applications to interoperate with future versions of the device interface software without recompilation. For example, take the case of a graphical application that is written to communicate CAN through a Komodo interface. At the time the program is built, the Komodo software is released as version 1.2. The Komodo interface software may be improved many months later resulting in increased performance and/or reliability; it is now released as version 1.3. The original application need not be altered or recompiled. The user can simply replace the old Komodo DLL with the newer one. How does this work? The application contains only a stub which in turn dynamically loads the DLL on the first invocation of any Komodo API function. If the DLL is replaced, the application simply loads the new one, thereby utilizing all of the improvements present in the replaced DLL.
On Linux and Mac OS X, the DLL is technically known as a shared object (SO).
3.6.2 DLL Location
Total Phase provides language bindings that can be integrated into any custom application. The default behavior of locating the Komodo DLL is dependent on the operating system platform and specific programming language environment. For example, for a C or C++ application, the following rules apply:
On a Windows system:
- The directory from which the application binary was loaded.
- The application's current directory.
-
32-bit system directory (for a 32-bit application). Examples:
- C:\Windows\System32 [Windows XP/Vista/7 32-bit]
- C:\Windows\System64 [Windows XP 64-bit]
- C:\Windows\SysWow64 [Windows Vista/7 64-bit]
-
64-bit system directory (for a 64-bit application). Examples:
- C:\Windows\System32 [Windows XP/Vista/7 64-bit]
- The Windows directory. (Ex: C:\Windows )
- The directories listed in the PATH environment variable.
On a Linux system this is as follows:
- First, search for the shared object in the application binary path. If the /proc filesystem is not present, this step is skipped.
- Next, search in the applications current working directory.
- Search the paths explicitly specified in LD_LIBRARY_PATH.
- Finally, check any system library paths as specified in /etc/ld.so.conf and cached in /etc/ld.so.cache.
On a Mac OS X system this is as follows:
- First, search for the shared object in the application binary path.
- Next, search in the applications current working directory.
- Search the paths explicitly specified in DYLD_LIBRARY_PATH.
- Finally, check the /usr/lib and /usr/local/lib system library paths.
If the DLL is still not found, an error will be returned by the binding function. The error code is KM_UNABLE_TO_LOAD_LIBRARY.
3.6.3 DLL Versioning
The Komodo DLL checks to ensure that the firmware of a given Komodo device is compatible. Each DLL revision is tagged as being compatible with firmware revisions greater than or equal to a certain version number. Likewise, each firmware version is tagged as being compatible with DLL revisions greater than or equal to a specific version number.
Here is an example:
DLL v1.20: compatible with Firmware >= v1.15 Firmware v1.30: compatible with DLL >= v1.20
Hence, the DLL is not compatible with any firmware less than version 1.15 and the firmware is not compatible with any DLL less than version 1.20. In this example, the version number constraints are satisfied and the DLL can safely connect to the target firmware without error. If there is a version mismatch, the API calls to open the device will fail. See the API documentation for further details.
3.7 Rosetta Language Bindings: API Integration into Custom Applications
3.7.1 Overview
The Komodo Rosetta language bindings make integration of the Komodo API into custom applications simple. Accessing Komodo functionality simply requires function calls to the Komodo API. This API is easy to understand, much like the ANSI C library functions, (e.g. there is no unnecessary entanglement with the Windows messaging subsystem like development kits for some other embedded tools).
First, choose the Rosetta bindings appropriate for the programming language. Different Rosetta bindings are included with the software distribution on the distribution CD. They can also be found in the software download package available on the Total Phase website. Currently the following languages are supported: C/C++, Python, Visual Basic 6, Visual Basic .NET, and C#. Next, follow the instructions for each language binding on how to integrate the bindings with your application build setup. As an example, the integration for the C language bindings is described below. For more information on how to integrate the bindings for other languages, please see the example code included on the distribution CD and also available for download on the Total Phase website.
- Include the komodo.h file included with the API software package in any C or C++ source module. The module may now use any Komodo API call listed in komodo.h.
- Compile and link komodo.c with your application. Ensure that the include path for compilation also lists the directory in which komodo.h is located if the two files are not placed in the same directory.
- Place the Komodo DLL, included with the API software package, in the same directory as the application executable or in another directory such that it will be found by the previously described search rules.
3.7.2 Versioning
Since a new Komodo DLL can be made available to an already compiled application, it is essential to ensure the compatibility of the Rosetta binding used by the application (e.g. komodo.c ) against the DLL loaded by the system. A system similar to the one employed for the DLL-Firmware cross-validation is used for the binding and DLL compatibility check. Here is an example:
DLL v1.20: compatible with Binding >= v1.10 Binding v1.15: compatible with DLL >= v1.15
The above situation will pass the appropriate version checks. The compatibility check is performed within the binding. If there is a version mismatch, the API function will return an error code, KM_INCOMPATIBLE_LIBRARY.
3.7.3 Customizations
While the provided language bindings stubs are fully functional, it is possible to modify the code found within this file according to specific requirements imposed by the application designer.
For example, in the C bindings one can modify the DLL search and loading behavior to conform to a specific paradigm. See the comments in komodo.c for more details.
3.8 Application Notes
3.8.1 Asynchronous Messages
There is buffering within the Komodo DLL, on a per-device basis, to help capture asynchronous messages. Take the case of the Komodo interface receiving CAN messages asynchronously. If the application calls the function to change the state of a GPIO while some unprocessed asynchronous messages are pending, the Komodo interface will modify the GPIO pin but also save any pending CAN messages internally. The messages will be held until the appropriate API function is called.
3.8.2 Receive Saturation
The Komodo interface can be configured as an active CAN node, or a passive monitor. A CAN channel can receive messages asynchronously with respect to the host PC software. Between calls to the Komodo API, these messages must be buffered somewhere in memory. This is accomplished on the PC host, courtesy of the operating system. Naturally, the buffer is limited in size and once this buffer is full, bytes will be dropped.
An overflow can occur when the Komodo device receives asynchronous messages faster than the rate that they are processed – the receive link is "saturated". This condition can affect other synchronous communication with the Komodo interface.
The receive saturation problem can be improved in two ways. The obvious solution is to reduce the amount of traffic that is sent by all CAN nodes between calls to the Komodo API. This will require the ability to reconfigure the offending CAN device(s). The other option is to poll the CAN channel to collect pending messages more frequently.
3.8.3 Threading
Each port on the Komodo interface is independent, and both can be used simultaneously in different threads. If the application design requires multi-threaded use of the Komodo functionality for a single port, each Komodo API call can be wrapped with a thread-safe locking mechanism before and after invocation. For more details, please see the API section.
3.8.4 USB Scheduling Delays
Each API call used to send data to and from the Komodo interface can incur up to 1 ms in delay on the PC host. This is caused by the inherent design of the USB architecture. The operating system will queue any outgoing USB transfer request on the host until the next USB frame period. The frame period is 1 ms. Thus, if the application attempts to execute several transactions in rapid sequence there can be 1-2 ms delay between each transaction plus any additional process scheduling delays introduced by the operating system.
4 Firmware
4.1 Field Upgrades
4.1.1 Upgrade Philosophy
The Komodo interface is designed so that its internal firmware can be upgraded by the user, thereby allowing the inclusion of any performance enhancements or critical fixes available after the purchase of the device. The upgrade procedure is performed via USB and has several error checking facilities to ensure that the Komodo interface is not rendered permanently unusable by a bad firmware update. In the worst case scenario, a corruption can cause the Komodo interface to be locked until a subsequent clean update is executed.
4.1.2 Upgrade Procedure
Here is the simple procedure by which the Komodo firmware is upgraded:
- Download the latest firmware from the Total Phase website.
- Unzip the downloaded file. It contains the kmflash utility. This utility contains the necessary information to perform the entire firmware update.
-
Run the appropriate version of kmflash :
- kmflash-windows.exe on Windows
- kmflash-linux on Linux
- kmflash-darwin on Mac OS X
It will first display the firmware version contained in the utility along with the required hardware version to run this firmware version. - It will list all of the detected devices along with their current firmware and hardware versions.
- Select a device to upgrade. If the selected devices hardware is not suitable to accept the new firmware, an error will be printed and the utility will be re-invoked.
- If the chosen device is acceptable, the kmflash utility will update the device with the new firmware. The process should take a few seconds, with a progress bar displayed during the procedure.
- The upgraded Komodo interface should now be usable by any Komodo-enabled application.
- In the event that there was a malfunction in the firmware update, the Komodo interface may not be recognizable by an Komodo-enabled application. Try the update again, since the Komodo interface has most likely become locked due to a corruption in the upgrade process. If the update still does not take effect, it is best to revert back to the previous firmware. This can be done by running a previous version of kmflash that contains an earlier firmware version. Check the Total Phase website or the distribution CD that was included with your Komodo interface for previous versions of the firmware.
5 API Documentation
5.1 Introduction
The API documentation that follows is oriented toward the Komodo Rosetta C bindings. The set of API functions and their functionality is identical regardless of which Rosetta language binding is utilized. The only differences are in the calling convention of the functions. For further information on such differences, please refer to the documentation that accompanies each language bindings in the Komodo software distribution.
5.2 General Data Types
The following definitions are provided for convenience. The Komodo API provides both signed and unsigned data types.
typedef unsigned char u08; typedef unsigned short u16; typedef unsigned int u32; typedef unsigned long long u64; typedef signed char s08; typedef signed short s16; typedef signed int s32; typedef signed long long s64;
5.3 Notes on Status Codes
Most of the Komodo API functions can return a status or error code back to the caller. The complete list of status codes is provided at the end of this chapter. All of the error codes are assigned values less than 0, separating these responses from any numerical values returned by certain API functions.
Each API function can return one of two error codes with regard to the loading of the underlying Komodo DLL, KM_UNABLE_TO_LOAD_LIBRARY and KM_INCOMPATIBLE_LIBRARY. If these status codes are received, refer to the previous sections in this datasheet that discuss the DLL and API integration of the Komodo software. Furthermore, all API calls can potentially return the error KM_UNABLE_TO_LOAD_FUNCTION. If this error is encountered, there is likely a serious version incompatibility that was not caught by the automatic version checking system. Where appropriate, compare the language binding versions (e.g., KM_HEADER_VERSION found in komodo.h and KM_CFILE_VERSION found in komodo.c ) to verify that there are no mismatches. Next, ensure that the Rosetta language binding (e.g., komodo.c and komodo.h) are from the same release as the Komodo DLL. If all of these versions are synchronized and there are still problems, please contact Total Phase support for assistance.
Any API function that accepts a Komodo handle can return the error KM_INVALID_HANDLE if the handle does not correspond to a valid Komodo device that has already been opened. If this error is received, check the application code to ensure that the km_open command returned a valid handle and that this handle is not corrupted before being passed to the offending API function.
Finally, any API call that communicates with a Komodo interface can return the error KM_COMMUNICATION_ERROR. This means that while the Komodo handle is valid and the communication channel is open, there was an error receiving the acknowledgment response from the Komodo interface. The error signifies that it was not possible to guarantee that the connected Komodo interface has processed the host PC request, though it is likely that the requested action has been communicated to the Komodo interface and the response was simply lost.
Komodo configuration functions require that a Komodo handle be in a disabled state. If a Komodo handle has been enabled by km_enable, these functions will return KM_NOT_DISABLED. Komodo CAN bus and GPIO data functions require that a Komodo handle be in an enabled state. If a Komodo handle has not been enabled by km_enable (or has been disabled by km_disable ), these functions will return KM_NOT_ENABLED.
These common status responses are not reiterated for each function. Only the error codes that are specific to each API function are described below.
All of the possible error codes, along with their values and status strings, are listed following the API documentation.
5.4 Notes on Features
Each Komodo CAN Duo device has two ports through which software applications can configure the device and communicate via CAN or GPIO. With multi-process access comes the possibility of two separate processes interfering with one another in a number of ways.
As a certain measure of protection, most CAN and GPIO API functions require certain resources to be possessed prior to successful execution. That is, a software process attempting to manipulate the CAN or GPIO interfaces through a port must first acquire certain feature resources from the Komodo CAN Duo device. These features are as follows:
| KM_FEATURE_GPIO_LISTEN | Read GPIO pin values |
| KM_FEATURE_GPIO_CONTROL | Set GPIO pin values |
| KM_FEATURE_GPIO_CONFIG | Configure GPIO pin directions |
| KM_FEATURE_CAN_A_LISTEN | Read CAN Channel A packets |
| KM_FEATURE_CAN_A_CONTROL | Send CAN Channel A packets |
| KM_FEATURE_CAN_A_CONFIG | Configure CAN Channel A parameters |
| KM_FEATURE_CAN_B_LISTEN | Read CAN Channel B packets |
| KM_FEATURE_CAN_B_CONTROL | Send CAN Channel B packets |
| KM_FEATURE_CAN_B_CONFIG | Configure CAN Channel B parameters |
The features are acquired and released using functions km_acquire and km_release, respectively.
Both ports on a single Komodo CAN Duo device can simultaneously possess the same CONTROL and LISTEN features. The CONFIG features, however, can only be possessed by one port at a time. Thus, it is possible for both ports to have simultaneous access to the CAN and GPIO interfaces, but it is not possible for one port to change certain vital configuration parameters the other port relies on.
The Komodo CAN Solo device has only one CAN channel but users are still required to acquire the resources before using them.
5.5 General
5.5.1 Interface
Find Devices (km_find_devices)
int km_find_devices (int num_ports, u16 *ports);
Get a list of ports through which Komodo devices can be accessed.
| num_ports | maximum number of ports to return |
| ports | array into which the port numbers are returned |
This function returns the number of ports found, regardless of the array size.
| None. |
Each element of the array is written with the port number.
Each Komodo device has two separate virtual ports. Each port represents a single element in the ports array. The ports from a single Komodo device always appear sequentially in the ports array.
Ports that are in use are OR'ed with KM_PORT_NOT_FREE ( 0x8000 ).
Examples:
Three Komodo devices are attached.
Both ports from device 0 are in-use. Both ports from the device 1 are free. The first port from device 2 is in-use and second port is free.
array => { 0x8000, 0x8001, 0x0002, 0x0003, 0x8004, 0x0005 }
If the input array is NULL, it is not filled with any values.
If there are more ports than the array size (as specified by num_ports ), only the first num_ports port numbers will be written into the array.
Find Devices (km_find_devices_ext)
int km_find_devices_ext (int num_ports, u16 *ports, int num_ids, u32 *unique_ids);
Get a list of ports, and corresponding unique IDs, through which Komodo devices can be accessed.
| num_ports | maximum number of ports to return |
| ports | array into which the port numbers are returned |
| num_ids | maximum number of unique IDs to return |
| unique_ids | array into which the unique IDs are returned |
This function returns the number of ports found, regardless of the array size.
| None. |
This function is the same as km_find_devices() except that is also returns the unique IDs of each Komodo port. Both ports on a physical Komodo device share the same ID. The IDs are guaranteed to be non-zero if valid.
The IDs are the unsigned integer representation of the 10-digit serial numbers.
The number of ports and IDs returned in each of their respective arrays is determined by the minimum of num_ports and num_ids. However, if either array is NULL, the length passed in for the other array is used as-is, and the NULL array is not populated. If both arrays are NULL, neither array is populated, but the number of devices found is still returned.
Open a Komodo port (km_open)
Komodo km_open (int port_number);
Open a Komodo port.
| port_number | The port is the same as the one obtained from function km_find_devices. It is a zero-based number. |
This function returns a Komodo handle, which is guaranteed to be greater than zero if valid.
| KM_UNABLE_TO_OPEN | The specified port is not associated with a Komodo device or the port is already in use. |
| KM_INCOMPATIBLE_DEVICE | There is a version mismatch between the DLL and the firmware. The DLL is not of a sufficient version for interoperability with the firmware version or vice versa. See km_open_ext() for more information. |
This function is recommended for use in simple applications where extended information is not required. For more complex applications, the use of km_open_ext() is recommended.
Open a Komodo port (km_open_ext)
Komodo km_open_ext (int port_number, KomodoExt *km_ext);
Open a Komodo port, returning extended information in the supplied structure.
| port_number | same as km_open |
| km_ext | pointer to a pre-allocated structure for extended version information available on open |
This function returns a Komodo handle, which is guaranteed to be greater than zero if valid.
| KM_UNABLE_TO_OPEN | The specified port is not associated with a Komodo device or the port is already in use. |
| KM_INCOMPATIBLE_DEVICE | There is a version mismatch between the DLL and the firmware. The DLL is not of a sufficient version for interoperability with the firmware version or vice versa. The version information will be available in the memory pointed to by km_ext. |
If 0 is passed as the pointer to the structure, this function will behave exactly like km_open().
The KomodoExt structure is described below:
struct KomodoExt { KomodoVersion version; /* Features of this device. */ int features; }
The features field denotes the capabilities of the Komodo port. See the API function km_features for more information.
The KomodoVersion structure describes the various version dependencies of Komodo components. It can be used to determine which component caused an incompatibility error.
struct KomodoVersion { /* Software, firmware, and hardware versions. */ u16 software; u16 firmware; u16 hardware; /* Firmware revisions that are compatible with this * software version. The top 16 bits gives the maximum * accepted fw revision. The lower 16 bits gives the * minimum accepted fw revision. */ u32 fw_revs_for_sw /* Hardware revisions that are compatible with this * software version. The top 16 bits gives the maximum * accepted hw revision. The lower 16 bits gives the * minimum accepted hw revision. */ u32 hw_revs_for_sw /* Software requires that the API interface must * be >= this version. */ u16 api_req_by_sw };
All version numbers are of the format:
(major << 8) | minor
example: v1.20 would be encoded as 0x0114.
The structure is zeroed before the open is attempted. It is filled with whatever information is available. For example, if the firmware version is not filled, then the device could not be queried for its version number.
This function is recommended for use in complex applications where extended information is required. For simpler applications, the use of km_open() is recommended.
Close a Komodo port (km_close)
int km_close (Komodo komodo);
Close a Komodo port.
| komodo | handle of a Komodo port to be closed |
The number of ports closed is returned on success. This will usually be 1.
| None. |
If the handle argument is zero, the function will attempt to close all possible handles, thereby closing all open Komodo ports. The total number of Komodo ports closed is returned by the function.
Get Supported Features (km_features)
int km_features (Komodo komodo);
Return the set of features supported by this port.
| komodo | handle of a Komodo port |
A mask of all features supported by the port is returned. Bitmask values are as defined in Table 6.
| None. |
The features mask returned by this function does not encode any information about the features currently available for use, or currently acquired by the port. The bitmask value only indicates the features that are supported by the port.
Get Unique ID (km_unique_id)
u32 km_unique_id (Komodo komodo);
Return the unique ID of the given Komodo port.
| komodo | handle of a Komodo port |
This function returns the unique ID for this Komodo interface. The IDs are guaranteed to be non-zero if valid. The ID is the unsigned integer representation of the 10-digit serial number.
| None. |
None.
Status String (km_status_string)
const char *km_status_string (int status);
Return the status string for the given status code.
| status | status code returned by a Komodo API function |
This function returns a human readable string that corresponds to status. If the code is not valid, it returns a NULL string.
| None. |
None.
Version (km_version)
int km_version (Komodo komodo, KomodoVersion *version);
Return the version matrix for the port associated with the given handle.
| komodo | handle of a Komodo port |
| version | pointer to pre-allocated structure |
A Komodo status code of KM_OK is returned on success or an error code as detailed in Table 23.
| None. |
If the handle is 0 or invalid, only the software version is set.
See the details of km_open_ext for the definition of KomodoVersion.
Sleep (km_sleep_ms)
u32 km_sleep_ms (u32 milliseconds);
Sleep for given amount of time.
| milliseconds | number of milliseconds to sleep |
This function returns the number of milliseconds slept.
| None. |
This function provides a convenient cross-platform function to sleep the current thread using standard operating system functions.
The accuracy of this function depends on the operating system scheduler. This function will return the number of milliseconds that were actually slept.
Acquire Features (km_acquire)
int km_acquire (Komodo komodo, u32 features);
Acquire features from the Komodo device.
| komodo | handle of a disabled Komodo port |
| features | bitmask of features to acquire as detailed in Table 6. |
A mask of all features acquired by the port is returned.
| None. |
The behavior of km_acquire is additive. Previously acquired features are never released by a call to km_acquire. Thus, it is possible to acquire various features through separate calls to km_acquire, though it is not necessary to do so.
Acquired features can be queried using a call to km_acquire with a features value of 0.
In the event that a specified feature cannot be acquired, an error will not occur. Instead, the returned feature mask will indicate which features are currently acquired.
Note: Both ports on a single Komodo can simultaneously possess the same CONTROL and LISTEN features. The CONFIG features can only be possessed by one port at a time.
Release Features (km_release)
int km_release (Komodo komodo, u32 features);
Release features to the Komodo device.
| komodo | handle of a disabled Komodo port |
| features | bitmask of features to release as detailed in Table 6. |
A mask of all features acquired by the port is returned.
| None. |
The behavior of km_release is subtractive. Previously acquired features are never released by a call to km_release unless they are specified in the features mask. Thus, it is possible to release various features through separate calls to km_release, though it is not necessary to do so.
Acquired features can be queried using a call to km_release with a features value of 0.
In the event that a specified feature cannot be released, an error will not occur. Instead, the returned feature mask will indicate which features are currently acquired.
Query Samplerate (km_get_samplerate)
int km_get_samplerate (Komodo komodo);
Query the Komodo device sampling rate.
| komodo | handle of a disabled Komodo port |
The current samplerate in Hz is returned.
| None. |
None.
Set Komodo Timeout (km_timeout)
int km_timeout (Komodo komodo, u32 timeout_ms);
Set the read timeout to the specified number of milliseconds.
| komodo | handle of a disabled Komodo port |
| timeout_ms | timeout value in milliseconds, or a special enumerated value, as shown in Table 7 |
| KM_TIMEOUT_IMMEDIATE | Return immediately |
| KM_TIMEOUT_INFINITE | Block indefinitely until data is received |
LISTEN must have been acquired on at least one feature.
A Komodo status code of KM_OK is returned on success or an error code as detailed in Table 23.
| None. |
This function sets the amount of time that km_can_read will wait before returning if the bus is idle. If km_can_read is called and there has been no new data on the bus for the specified timeout interval, the function will return with the KM_READ_TIMEOUT flag of the status value set.
If the timeout is set to KM_TIMEOUT_IMMEDIATE, calls to km_can_read will always return immediately.
If the timeout is set to KM_TIMEOUT_INFINITE, calls to km_can_read will block indefinitely until the Komodo port receives data from the CAN bus, or detects a GPIO event.
Calls to km_can_read are OS dependent, and thus the supplied timeout value cannot be guaranteed by the API.
Set Komodo Latency (km_latency)
int km_latency (Komodo komodo, u32 latency_ms);
Set the maximum latency to the specified number of milliseconds.
| komodo | handle of a disabled Komodo port |
| latency_ms | latency value in milliseconds |
LISTEN must have been acquired on at least one feature.
A Komodo status code of KM_OK is returned on success or an error code as detailed in Table 23.
| None. |
Set the capture latency to the specified number of milliseconds.
The capture latency effectively splits up the total amount of buffering into smaller individual buffers. Only once one of these individual buffers is filled, does the read function return. Therefore, in order to fulfill shorter latency requirements, these individual buffers are set to a smaller size. If a larger latency is requested, then the individual buffers will be set to a larger size.
Setting a small latency can increase the responsiveness of the read function. It is important to keep in mind that there is a fixed cost to processing each individual buffer that is independent of buffer size. Therefore, the trade-off is that using a small latency will increase the overhead per byte buffered. A large latency setting decreases that overhead, but increases the amount of time that the library must wait for each buffer to fill before the library can process their contents.
This setting is distinctly different from the timeout setting. The latency time should be set to a value shorter than the timeout.
5.6 CAN Interface
5.6.1 CAN Notes
-
The Komodo CAN Duo supports two CAN channels. Some CAN API functions require a CAN channel with an enumerated type of km_can_ch_t. This enumerated type is described in Table 8.
Table 8 : CAN Channel Enumerated TypeKM_CAN_CH_A CAN Channel A KM_CAN_CH_B CAN Channel B
For the Komodo CAN Solo, the channel should always be KM_CAN_CH_A for all CAN API functions requiring it. -
The Komodo has a limited buffer used to buffer CAN packets and CAN events. If this buffer is filled, the Komodo will not report new packets or events, and it will stop transmitted packes on the CAN bus. This situation can be detected by seeing a KM_READ_END_OF_CAPTURE in the status field of the km_can_info_t struct from the km_can_read function. Also, in this situation the CAN write functions will return with an error code of KM_CAN_SEND_FAIL.
To decrease the possibility of this buffer filling, the following steps may be taken:
- Ensure the CAN bus is properly terminated, otherwise the Komodo is saturated with CAN errors.
- Use only one port on the Komodo device.
- Use only one CAN channel on the Komodo device.
- Use a lower CAN bitrate.
5.6.2 General CAN
Configure CAN (km_can_configure)
int km_can_configure (Komodo komodo, u32 config);
Configure the CAN interface.
| komodo | handle of a disabled Komodo port |
| config | Either KM_CAN_CONFIG_NONE for the default configuration or a bitmask of the flags shown in Table 9 for a custom configuration. |
| KM_CAN_CONFIG_LISTEN_SELF | CAN traffic generated by the Komodo will be returned through km_can_read. |
LISTEN must have been acquired on at least one channel.
A Komodo status code of KM_OK is returned on success or an error code as detailed in Table 23.
| None. |
If KM_CAN_CONFIG_LISTEN_SELF is set, all CAN traffic generated by the Komodo will be returned through km_can_read. This includes host-generated packets from both Komodo ports.
Otherwise, Komodo-generated traffic will not be returned through km_can_read. This is the default behavior.
Set CAN Bus Timeout (km_can_bus_timeout)
int km_can_bus_timeout (Komodo komodo, km_can_ch_t channel, u16 timeout_ms);
Set the timeout for CAN packets awaiting transmission.
| komodo | handle of a disabled Komodo port |
| channel | the CAN channel for which to set the timeout value |
| timeout_ms | the timeout value in milliseconds |
CONTROL must have been acquired on the selected channel.
The function returns the new timeout value in milliseconds.
| None. |
The timeout timer for a CAN submission begins when the packet is first given to the CAN controller on the Komodo. If the timeout is reached before the packet is transmitted successfully on the CAN bus, KM_CAN_SEND_TIMEOUT will be returned by km_can_write or km_can_async_collect.
The actual timeout value will not always be set to timeout_ms. The timeout is set to the closest permissible timeout value that is greater than or equal to timeout_ms. This function returns the actual timeout value in milliseconds.
Set CAN Bitrate (km_can_bitrate)
int km_can_bitrate (Komodo komodo, km_can_ch_t channel, u32 bitrate_hz);
Set the bitrate for CAN packet reception and transmission.
| komodo | handle of a disabled Komodo port |
| channel | the CAN channel for which to set the bitrate |
| bitrate_hz | bitrate value in hertz |
CONFIG must have been acquired on the selected channel.
The function returns the new bitrate value in hertz.
The actual bitrate value will not always be set to bitrate_hz. The bitrate is set to the closest permissible bitrate value that is greater than or equal to bitrate_hz. The maximum allowable bitrate is 1 MHz.
If bitrate_hz is set to 0, the Komodo device will simply return the current bitrate set.
Auto-detect CAN Bitrate (km_can_auto_bitrate)
int km_can_auto_bitrate (Komodo komodo, km_can_ch_t channel);
Automatically set the bitrate for CAN packet reception and transmission.
| komodo | handle of a disabled Komodo port |
| channel | the CAN channel for which to auto-detect the bitrate |
CONFIG must have been acquired on the selected channel.
The function returns the new bitrate value in hertz.
| KM_CAN_AUTOBITRATE_FAIL | Unable to detect a bitrate. |
This function provides an easy mechanism for auto-detecting the bitrate. It is equivalent to calling km_can_auto_bitrate_ext with the following bitrates:
- 1000000
- 500000
- 250000
- 125000
- 100000
- 50000
- 25000
- 20000
Auto-detect CAN Bitrate Extended (km_can_auto_bitrate_ext)
int km_can_auto_bitrate_ext (Komodo komodo, km_can_ch_t channel, u32 num_bitrate_hz, u32 *bitrates_hz);
Automatically set the bitrate for CAN packet reception and transmission with extended options.
| komodo | handle of a disabled Komodo port |
| channel | the CAN channel for which to auto-detect the bitrate |
| num_bitrates_hz | number of items in the bitrate_hz array |
| bitrates_hz | list of bitrates |
CONFIG must have been acquired on the selected channel.
The function returns the new bitrate value in hertz.
| KM_CAN_AUTOBITRATE_FAIL | Unable to detect a bitrate. |
This function takes in a list of potential bitrates on the bus. It will attempt each bitrate in order for up to 500 ms before attempting a new bitrate. If a successfully completed packet is perceived by the channel, then that bitrate is deemed a success, and the bitrate is returned.
If the function is unable to find a successful packet for any of the bitrates within the alotted time, it will return KM_CAN_AUTOBITRATE_FAIL.
The actual bitrate value will not always be set to the values in bitrates_hz. The bitrate is set to the closest permissible bitrate value that is greater than or equal to the value in bitrates_hz. The maximum allowable bitrate is 1 MHz.
Set Target Power (km_can_target_power)
int km_can_target_power (Komodo komodo, km_can_ch_t channel, km_power_t power);
Set the target power option on a CAN channel.
| komodo | handle of a disabled Komodo port |
| channel | the CAN channel for which to set target power |
| power | the desired power setting, as described in Table 10 |
| KM_TARGET_POWER_OFF | Disable target power. |
| KM_TARGET_POWER_ON | Enable target power. |
| KM_TARGET_POWER_QUERY | Query target power. |
CONFIG must have been acquired on the supplied channel.
The current state of the target power pin on the supplied CAN channel will be returned. The configuration will be described by the same values as in the table above.
| None. |
None.
Port Enable (km_enable)
int km_enable (Komodo komodo);
Enable the port associated with the provided handle.
| komodo | handle of a disabled Komodo port |
Either LISTEN or CONTROL must have been acquired on at least one feature.
A Komodo status code of KM_OK is returned on success or an error code as detailed in Table 23.
| None. |
This function enables LISTEN and CONTROL features acquired by the provided port. The port must have acquired at least one of these features, and must not be active prior to calling km_enable.
If another port on the Komodo device is active with only the CAN LISTEN feature, and this port has the CAN CONTROL feature, then the other port may experience brief packet loss when this port is enabled, and the CAN channel is changed to an active participant on the bus.
Port Disable (km_disable)
int km_disable (Komodo komodo);
Disable the port associated with the provided handle.
| komodo | handle of an enabled Komodo port |
None.
A Komodo status code of KM_OK is returned on success or an error code as detailed in Table 23.
| None. |
This function disables active LISTEN and CONTROL functionality on the provided port. The port must be active prior to calling km_disable.
If another port on the Komodo device is active with only the CAN LISTEN feature, and this port has the CAN CONTROL feature, then the other port may experience brief packet loss when this port is disabled, and the CAN channel is reverted to listen-only mode.
Query CAN Bus State (km_can_query_bus_state)
int km_can_bus_state (Komodo komodo, km_can_ch_t channel, u08 *bus_state, u08 *rx_error, u08 *tx_error);
Query the current state of the provided CAN channel.
| komodo | handle of an enabled Komodo port |
| channel | the CAN channel for which to query error counters |
| bus_state | filled with the current CAN state enumerated value as shown in Table 11 |
| rx_error | filled with the total number of CAN RX errors |
| tx_error | filled with the total number of CAN TX errors |
| KM_CAN_BUS_STATE_LISTEN_ONLY | Listen only mode |
| KM_CAN_BUS_STATE_CONTROL | Control mode |
| KM_CAN_BUS_STATE_WARNING | Warning state |
| KM_CAN_BUS_STATE_ACTIVE | Active error state |
| KM_CAN_BUS_STATE_PASSIVE | Passive error state |
| KM_CAN_BUS_STATE_OFF | Bus-off condition |
Either CONFIG or LISTEN must have been acquired on the selected channel.
A Komodo status code of KM_OK is returned on success or an error code as detailed in Table 23.
| None. |
Queries the provided CAN channels controller for its state and its error counts.
CAN Read (km_can_read)
int km_can_read (Komodo komodo, km_can_info_t *info, km_can_packet_t *packet, int num_bytes, u08 *data);
Read a packet or info from a Komodo port.
| komodo | handle of an enabled Komodo port |
| info | filled with CAN bus information along with status and events |
| packet | filled with CAN packet parameters |
| num_bytes | length of the data array |
| data | an allocated array of u08 which is filled with the received data |
LISTEN must have been acquired for at least one feature.
A Komodo status code of KM_OK is returned on success or an error code as detailed in Table 23.
| KM_READ_EMPTY | No data was available for a non-blocking call. |
Timeouts
The timeout value for km_can_read is configurable using km_timeout. The km_timeout function sets the amount of time that km_can_read will block before returning if the bus is idle.
If km_can_read is called and there has been no new data on the bus for the specified timeout interval, the function will return with the KM_READ_TIMEOUT flag of the status value set. An exception to this exists if info is a NULL pointer. In this case, the function returns KM_OK.
If the timeout value is set to KM_TIMEOUT_IMMEDIATE, this function is non-blocking. If no data is immediately available, the function returns KM_CAN_READ_EMPTY.
If the timeout value is set to KM_TIMEOUT_INFINITE, this function will block indefinitely until the Komodo port receives data on the CAN bus or a GPIO event.
CAN Packet Struct
A CAN packet struct type, km_can_packet_t, is used to provide information about the CAN packet received on the bus on calls to km_can_read. This same struct is used for the CAN transmit functions.
struct km_can_packet_t { u08 remote_req; u08 extend_addr; u08 dlc; u32 id; };
| remote_req | A flag set if the packet is a remote frame. |
| extend_addr | A flag set if the packet is using the 29 bit identifier. |
| dlc | The data length code field. |
| id | The identifier field. |
CAN Info Struct
A CAN info struct type, km_can_info_t, is used to provide important meta information about the CAN bus or other events, on calls to km_can_read.
/* CAN bus information */ struct km_can_info_t { u64 timestamp; u32 status; u32 events; km_can_ch_t channel; u32 bitrate_hz; u08 host_gen; u08 rx_error_count; u08 tx_error_count; u32 overflow_count; };
| timestamp | The timestamp of when the packet or event began |
| status | Status mask as described in Table 14 |
| events | Event mask as described in Table 15 |
| channel | The channel on which the packet or event occurred |
| bitrate_hz | The bitrate of the CAN bus in hertz |
| host_gen | Indicates a host generated packet or event |
| rx_error_count | CAN RX error counter |
| tx_error_count | CAN TX error counter |
| overflow_count | Read queue overflow counter |
| KM_READ_TIMEOUT | The read timeout limit was reached |
| KM_READ_ERR_OVERFLOW | Packet loss due to insufficient read rate |
| KM_READ_END_OF_CAPTURE | Capture ended |
| Status Codes for CAN Errors | |
| KM_READ_CAN_ERR | CAN Error has occurred |
| KM_READ_CAN_ERR_FULL_MASK | A bitmask for the entire CAN error |
| Status Codes for CAN Error Position | |
| KM_READ_CAN_ERR_POS_MASK | A bitmask for the position of the error |
| KM_READ_CAN_ERR_POS_SOF | Error at the Start of Frame |
| KM_READ_CAN_ERR_POS_ID28_21 | Error at ID28 - ID21 bits |
| KM_READ_CAN_ERR_POS_ID20_18 | Error at ID20 - ID18 bits |
| KM_READ_CAN_ERR_POS_SRTR | Error at the SRTR bit |
| KM_READ_CAN_ERR_POS_IDE | Error at the IDE bit |
| KM_READ_CAN_ERR_POS_ID17_13 | Error at ID17 - ID13 bits |
| KM_READ_CAN_ERR_POS_ID12_5 | Error at the ID12 - ID5 bits |
| KM_READ_CAN_ERR_POS_ID4_0 | Error at the ID4 - ID0 bits |
| KM_READ_CAN_ERR_POS_RTR | Error at the RTR bit |
| KM_READ_CAN_ERR_POS_RSVD_1 | Error at Reserved Bit 1 |
| KM_READ_CAN_ERR_POS_RSVD_0 | Error at Reserved Bit 0 |
| KM_READ_CAN_ERR_POS_DLC | Error at the Data Length Code |
| KM_READ_CAN_ERR_POS_DF | Error at the Data Field |
| KM_READ_CAN_ERR_POS_CRC_SEQ | Error at the CRC Seqeuence |
| KM_READ_CAN_ERR_POS_CRC_DEL | Error at the CRC Delimiter |
| KM_READ_CAN_ERR_POS_ACK_SLOT | Error at the Acknowledge Slot |
| KM_READ_CAN_ERR_POS_ACK_DEL | Error at the Acknowledge Delimiter |
| KM_READ_CAN_ERR_POS_EOF | Error at the End of Frame |
| KM_READ_CAN_ERR_POS_INTRMSN | Error at the Intermission |
| KM_READ_CAN_ERR_POS_AEF | Error at the Active Error Flag |
| KM_READ_CAN_ERR_POS_PEF | Error at the Passive Error Flag |
| KM_READ_CAN_ERR_POS_TDB | Error at the Tolerate Dominant Bits |
| KM_READ_CAN_ERR_POS_ERR_DEL | Error at the Error Delimiter |
| KM_READ_CAN_ERR_POS_ERR_OVRFLG | Error at the Overload Flag |
| Status Codes for CAN Error Direction | |
| KM_READ_CAN_ERR_DIR_MASK | A bit mask for the direction of the error |
| KM_READ_CAN_ERR_DIR_TX | Error during transmission. |
| KM_READ_CAN_ERR_DIR_RX | Error during reception. |
| Status Codes for CAN Error Type | |
| KM_READ_CAN_ERR_TYPE_MASK | A bit mask for the type of the error |
| KM_READ_CAN_ERR_TYPE_BIT | Bit type error |
| KM_READ_CAN_ERR_TYPE_FORM | Form type error |
| KM_READ_CAN_ERR_TYPE_STUFF | Stuff type error |
| KM_READ_CAN_ERR_TYPE_OTHER | Other type error |
| Status Codes for CAN Arbitration Loss | |
| KM_READ_CAN_ARB_LOST | CAN controller lost arbitration |
| KM_READ_CAN_ARB_LOST_POS_MASK | Mask to determine the position of arbitration loss |
| KM_EVENT_DIGITAL_INPUT | Digital input detected |
| KM_EVENT_DIGITAL_INPUT_MASK | Digital input bit mask |
| KM_EVENT_DIGITAL_INPUT_N | Digital input detected on pin N |
| KM_EVENT_CAN_BUS_STATE_LISTEN_ONLY | Entered Listen Mode |
| KM_EVENT_CAN_BUS_STATE_CONTROL | Entered Control Mode |
| KM_EVENT_CAN_BUS_STATE_WARNING | Reached Warning State |
| KM_EVENT_CAN_BUS_STATE_ACTIVE | Entered Active Error Mode |
| KM_EVENT_CAN_BUS_STATE_PASSIVE | Entered Passive Error Mode |
| KM_EVENT_CAN_BUS_STATE_OFF | Inactive state entered |
| KM_EVENT_CAN_BUS_BITRATE | Bitrate update event |
Asynchronous CAN Submit (km_can_async_submit)
int km_can_async_submit (Komodo komodo, km_can_ch_t channel, u08 flags, const km_can_packet_t *packet, int num_bytes, const u08 *data);
Asynchronously submit a CAN packet.
| komodo | handle of an enabled Komodo port |
| channel | the CAN channel on which to submit the packet |
| flags | special operations as described in Table 16 |
| packet | pre-allocated structure containing CAN packet parameters, see Table 12 |
| num_bytes | size of the data array |
| data | pre-allocated array containing CAN packet data |
| KM_CAN_FLAGS_ONE_SHOT | Only attempt to transmit the packet once. Do not retransmit. |
CONTROL must have been acquired on the selected channel.
A Komodo status code of KM_OK is returned on success or an error code as detailed in Table 23.
| KM_CAN_ASYNC_MAX_REACHED | There are too many outstanding CAN packets |
This function asynchronously submits a CAN packet to the Komodo port for transmission on the CAN bus. As an asynchrnonous call, this function will not block.
If the KM_CAN_FLAGS_ONE_SHOT bit is set in flags, the packet will be sent as a one-shot transmission. Only one attempt will be made to transmit the packet on the CAN bus in this case.
The response to an asynchronous CAN submission should be collected with a call to km_can_async_collect.
Asynchronous CAN Collect (km_can_async_collect)
int km_can_async_collect (Komodo komodo, u32 timeout_ms, u32 *arbitration_count);
Collect the response to a previously submitted CAN packet.
| komodo | handle of an enabled Komodo port |
| timeout_ms | timeout value |
| arbitration_count | filled with the number of packets lost because of arbitration loss |
None.
A Komodo status code of KM_OK is returned on success or an error code as detailed in Table 23.
| KM_CAN_ASYNC_EMPTY | There are no submitted CAN packets |
| KM_CAN_ASYNC_TIMEOUT | The function timed out waiting for a response |
| KM_CAN_SEND_TIMEOUT | The packet timedout |
| KM_CAN_SEND_FAIL | Transmission failed |
This function blocks for up to timeout_ms until a response is available for collection from the port. If a successful response is collected, KM_OK is returned. If the submitted packet timed out, KM_CAN_SEND_TIMEOUT is returned.
If the internal buffer on the Komodo device is overflowed KM_CAN_SEND_FAIL is returned. This error will be returned until the Komodo device is disabled.
The arbitration_count field is set based on the number of arbitration errors observed before the CAN packet timed out, or was transmitted successfully.
If the timeout_ms value is reached before any response is collected from the port, the function will return KM_CAN_ASYNC_TIMEOUT.
CAN Write (km_can_write)
int km_can_write (Komodo komodo, km_can_ch_t channel, u08 flags, const km_can_packet_t *packet, int num_bytes, const u08 *data, u32 *arbitration_count);
Issue a packet to be transmitted on the CAN bus, and block until a response is recieved.
| komodo | handle to an enabled Komodo port |
| channel | the CAN channel on which to submit the packet |
| flags | See flag field as described in Section 5.6.2.11 |
| packet | pre-allocated structure containing CAN packet parameters |
| num_bytes | size of the data array |
| data | pre-allocated array containing CAN packet data |
| arbitration_count | filled with the number of transmissions failed due to arbitration loss |
CONTROL must have been acquired on the selected channel.
A Komodo status code of KM_OK is returned on success or an error code as detailed in Table 23.
| KM_CAN_ASYNC_PENDING | Uncollected asynchronously submitted packets must be collected |
This function simply acts as a wrapper for the asynchronous submit and collect functions.
km_can_async_submit(komodo, channel, flags, packet, num_bytes, data); km_can_async_collect(komodo, KM_TIMEOUT_INFINITE, arbitration_count);
The CAN packet is submitted asynchronously, and km_can_async_collect is called with KM_TIMEOUT_INFINITE to block indefinitely until a response is received.
A KM_CAN_ASYNC_PENDING error is returned if there are any uncollected asynchronously submitted packets. Packets submitted with km_can_async_submit should always be collected using km_can_async_collect.
5.7 GPIO Interface
5.7.1 GPIO Notes
- When the GPIO pin is configured as an input, the input change event reporting is limited to one edge transition every 20 us across all pins.
- When the GPIO pin is configured as an output controlled by a CAN bus event, the pin will toggle with a pulse duration of about 200 ns.
5.7.2 GPIO Interface
Configure GPIO Input Pin (km_gpio_config_in)
int km_gpio_config_in (Komodo komodo, u08 pin_number, u08 bias, u08 trigger);
Configure a GPIO input pin.
| KM_GPIO_PIN_1_CONFIG | GPIO Pin 1 |
| KM_GPIO_PIN_2_CONFIG | GPIO Pin 2 |
| KM_GPIO_PIN_3_CONFIG | GPIO Pin 3 |
| KM_GPIO_PIN_4_CONFIG | GPIO Pin 4 |
| KM_GPIO_PIN_5_CONFIG | GPIO Pin 5 |
| KM_GPIO_PIN_6_CONFIG | GPIO Pin 6 |
| KM_GPIO_PIN_7_CONFIG | GPIO Pin 7 |
| KM_GPIO_PIN_8_CONFIG | GPIO Pin 8 |
| KM_PIN_BIAS_TRISTATE | No modification to input voltage |
| KM_PIN_BIAS_PULLUP | Pulls up input voltage using high impedance resistor to 3.3 V |
| KM_PIN_BIAS_PULLDOWN | Pulls down input voltage using high impedance resistor to GND |
| KM_PIN_TRIGGER_NONE | Do not report pin changes |
| KM_PIN_TRIGGER_RISING_EDGE | Report change on a rising input edge |
| KM_PIN_TRIGGER_FALLING_EDGE | Report change on a falling input edge |
| KM_PIN_TRIGGER_BOTH_EDGES | Report change on either a rising or falling input edge |
GPIO CONFIG must have been acquired.
A Komodo status code of KM_OK is returned on success or an error code as detailed in Table 23.
| None. |
The trigger parameter defines when an input change event is reported by the km_can_read function and is not related to triggering the Komodo interface to start collecting data. As an example, if an input pin is configured to KM_PIN_TRIGGER_FALLING_EDGE, an input change event will only be reported on the falling edge and not the rising edge.
Configure GPIO Output Pin (km_gpio_config_out)
int km_gpio_config_out (Komodo komodo, u08 pin_number, u08 drive, u08 source);
Configure a GPIO output pin.
| KM_PIN_DRIVE_NORMAL | Active 3.3 V; Inactive GND |
| KM_PIN_DRIVE_INVERTED | Active GND; Inactive 3.3 V |
| KM_PIN_DRIVE_OPEN_DRAIN | Active GND; Inactive FLOAT |
| KM_PIN_DRIVE_OPEN_DRAIN_PULLUP | Equivalent to KM_PIN_OPEN_DRAIN with a high impedance pullup |
| KM_PIN_SRC_SOFTWARE_CTL | Controlled using km_gpio_set. |
| KM_PIN_SRC_ALL_ERR_CAN_A | Active on any CAN A error |
| KM_PIN_SRC_BIT_ERR_CAN_A | Active on CAN A Bit Error |
| KM_PIN_SRC_FORM_ERR_CAN_A | Active on CAN A Form Error |
| KM_PIN_SRC_STUFF_ERR_CAN_A | Active on CAN A Stuff Error |
| KM_PIN_SRC_OTHER_ERR_CAN_A | Active on CAN A Other Error |
| KM_PIN_SRC_ALL_ERR_CAN_B | Active on any CAN B error |
| KM_PIN_SRC_BIT_ERR_CAN_B | Active on CAN B Bit Error |
| KM_PIN_SRC_FORM_ERR_CAN_B | Active on CAN B Form Error |
| KM_PIN_SRC_STUFF_ERR_CAN_B | Active on CAN B Stuff Error |
| KM_PIN_SRC_OTHER_ERR_CAN_B | Active on CAN B Other Error |
| KM_PIN_SRC_ALL_ERR_CAN_BOTH | Active on any CAN A or B error |
| KM_PIN_SRC_BIT_ERR_CAN_BOTH | Active on CAN A or B Bit Error |
| KM_PIN_SRC_FORM_ERR_CAN_BOTH | Active on CAN A or B Form Error |
| KM_PIN_SRC_STUFF_ERR_CAN_BOTH | Active on CAN A or B Stuff Error |
| KM_PIN_SRC_OTHER_ERR_CAN_BOTH | Active on CAN A or B Other Error |
GPIO CONFIG must have been acquired.
A Komodo status code of KM_OK is returned on success or an error code as detailed in Table 23.
| None. |
None.
Get (km_gpio_get)
int km_gpio_get (Komodo komodo);
Get the value of current GPIO pins as a bitmask.
| komodo | handle of a Komodo port |
None.
Returns the current value of all GPIO pins, input and output.
| None. |
None.
Set (km_gpio_set)
int km_gpio_set (Komodo komodo, u08 value, u08 mask);
Set the value of current GPIO outputs.
| komodo | handle of a Komodo port |
| value | value to which to set the pins provided in mask |
| mask | a bitmask specifying which outputs should be set to the supplied value (see Table 22). |
| KM_GPIO_PIN_1_MASK | GPIO Pin 1 Mask |
| KM_GPIO_PIN_2_MASK | GPIO Pin 2 Mask |
| KM_GPIO_PIN_3_MASK | GPIO Pin 3 Mask |
| KM_GPIO_PIN_4_MASK | GPIO Pin 4 Mask |
| KM_GPIO_PIN_5_MASK | GPIO Pin 5 Mask |
| KM_GPIO_PIN_6_MASK | GPIO Pin 6 Mask |
| KM_GPIO_PIN_7_MASK | GPIO Pin 7 Mask |
| KM_GPIO_PIN_8_MASK | GPIO Pin 8 Mask |
CONTROL must have been acquired.
A Komodo status code of KM_OK is returned on success or an error code as detailed in Table 23.
| None. |
This function sets the value of any GPIO pins configured as software controlled outputs. Any attempts to set a pin configured as either an input or as a non-software-controlled output will be silently ignored.
5.8 Error Codes
| Literal Name | Value | km_status_string() return value |
| KM_OK | 0 | ok |
| KM_UNABLE_TO_LOAD_LIBRARY | -1 | unable to load library |
| KM_UNABLE_TO_LOAD_DRIVER | -2 | unable to load USB driver |
| KM_UNABLE_TO_LOAD_FUNCTION | -3 | unable to load binding function |
| KM_INCOMPATIBLE_LIBRARY | -4 | incompatible library version |
| KM_INCOMPATIBLE_DEVICE | -5 | incompatible device version |
| KM_COMMUNICATION_ERROR | -6 | communication error |
| KM_UNABLE_TO_OPEN | -7 | unable to open device |
| KM_UNABLE_TO_CLOSE | -8 | unable to close device |
| KM_INVALID_HANDLE | -9 | invalid device handle |
| KM_CONFIG_ERROR | -10 | configuration error |
| KM_PARAM_ERROR | -11 | parameter error |
| KM_FUNCTION_NOT_AVAILABLE | -12 | function not available |
| KM_FEATURE_NOT_ACQUIRED | -13 | necessary feature not acquired |
| KM_NOT_DISABLED | -14 | port must be disabled |
| KM_NOT_ENABLED | -15 | port must be enabled |
| KM_CAN_READ_EMPTY | -101 | CAN nothing to read |
| KM_CAN_SEND_TIMEOUT | -102 | CAN send timed out |
| KM_CAN_SEND_FAIL | -103 | CAN send failed |
| KM_CAN_ASYNC_EMPTY | -104 | CAN no responses available |
| KM_CAN_ASYNC_MAX_REACHED | -105 | CAN async submit limit reached |
| KM_CAN_ASYNC_PENDING | -106 | CAN async packets pending |
| KM_CAN_ASYNC_TIMEOUT | -107 | CAN async collect timed out |
| KM_CAN_AUTO_BITRATE_FAIL | -108 | Unable to detect a bitrate |
6 Legal / Contact
6.1 Disclaimer
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Information in this document is subject to change without notice and should not be construed as a commitment by Total Phase. While the information contained herein is believed to be accurate, Total Phase assumes no responsibility for any errors and/or omissions that may appear in this document.
6.2 Life Support Equipment Policy
Total Phase products are not authorized for use in life support devices or systems. Life support devices or systems include, but are not limited to, surgical implants, medical systems, and other safety-critical systems in which failure of a Total Phase product could cause personal injury or loss of life. Should a Total Phase product be used in such an unauthorized manner, Buyer agrees to indemnify and hold harmless Total Phase, its officers, employees, affiliates, and distributors from any and all claims arising from such use, even if such claim alleges that Total Phase was negligent in the design or manufacture of its product.
6.3 Contact Information
Total Phase can be found on the Internet at http://www.totalphase.com/. If you have support-related questions, please go to the Total Phase website. For sales inquiries, please contact [email protected].
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All rights reserved.