How Do I Use the Combined I2C Format for 7-Bit Addresses?
2019-07-11
Rena Ayeras
Question from the Customer:

I am working with the Aardvark I2C/SPI Host Adapter, and I need to apply the I2C Combined Format. Looking at the Aardvark I2C/SPI Host Adapter User Manual, I see Aardvark API Software is available for doing that, but for ease of use, I would prefer a GUI application.

Also, I don’t need 10-bit addresses for my project. The API commands seem to imply I need to do that – is there a way I can use 7-bit addresses instead?

Response from Technical Support:

Thanks for your question! For your application, you can use our  Control Center Serial Software, an easy-to-use GUI application that provides access to all the I2C and SPI functions of the Aardvark adapter, including Combined Format.

When using I2C protocols, including Combined Format, the 7-bit address is default. The 10-bit API command that you saw in the Aardvark User manual, AA_I2C_10_BIT_ADDR, only needs to be executed to work with 10-bit addresses.

Example of Combined I2C Format with 7-Bit Address

Here is an example of using the Combined Format with 7-bit addresses.

Combined Format with 7-bit addresses Combined Format with 7-bit addresses

Combined Format Details

  • Write 17 bytes with no stop bit to 7-bit Slave address 0x63 starting at offset 00.

  • Master Read 18 bytes with a stop bit.

The following settings to use (select the check box) in the Control Center Serial Software:

      1. In the Master dialog:

        • Uncheck 10-Bit Addr.

        • Check Combined FMT and No Stop.

        • Set the Slave Address to 0x63

      2. In the Master Register Read section:

      3. Enter the following parameters under Master Register Read:

        • Register Address : 0x03

        • Address Width : 1 byte

        • Number of Data Bytes : 18

      4. Click the Master Register Read

For more information about I2C Combined formats, please refer to the Philips I2C Bus Specification at www.I2C-Bus.org.

Additional resources that you may find helpful include the following:

We hope this answers your question. Looking for more information? You can contact us and request a demo that applies to your application, as well as ask about our Total Phase products.

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