I just started using your Cheetah^TM SPI Host Adapter and high speed flash sockets to program 1.8V Micron flash devices, N25Q064A.

The Total Phase socket boards I use provide about 3V for VCC, even when I select a 1.8V part type. Otherwise, this seems to program correctly. When I attach the Cheetah SPI Host Adapter to my custom socket board (where the flash device is powered by 1.8V), I cannot program the flash device. However, I can program it from my micro controller. I have isolated the flash part from the micro controller and I still cannot program the device at 1.8V with the Cheetah host adapter. What should I be doing?

Also, I tried running signals as slowly as the Flash Center allows, and I checked that all signals go to their correct places. What is see on the scope shows there may be a timing issue - I need to add a delay. How can I adjust the timing?

Thanks for your questions! The Cheetah SPI Host Adapter operates at 3.3V signal levels. The Total Phase SPI Flash Socket Boards (SOIC-8 and SOIC-16) support memory parts with SPI 3.3V logic level voltage. The Total Phase SPI socket boards cannot be configured to a lower logic level voltage (such as 1.8V). It is possible that the boards work in your system due to voltage margins. There may be also be some voltage margin in the 1.8V N25Q064 memory part. In addition, the two board designs are not identical. There may be some differences between the board design of your custom board and the Total Phase socket board.

To communicate with devices that operate at a lower voltage (such as the 1.8V device on your custom board), we recommend using a Level Shifter Board between the Cheetah host adapter and the target device. This setup will provide the correct SPI signals level to both devices.

Some of the Cheetah SPI timing parameters can be configured when using the appropriate software.

• When using the Flash Center^TM Software (and its XML file), you cannot change the Cheetah timing parameters.
• When using the Cheetah Software API, you can also configure the Cheetah timing parameters. For additional information about the Cheetah API, please refer to section 5 of the Cheetah Host Adapter User Manual.
• When using the Cheetah GUI Software, you can change the delay parameter in the Cheetah GUI window, as shown below.

Figure 1: Cheetah SPI Host Adapter GUI Window

Figure 2: Cheetah SPI Host Adapter Parameters

 

 Table 1: Cheetah SPI Timing Parameters

Symbol	Parameter	Min	Max	Units
t clk	Clock period	25	10000	ns
t e	Output Enable to SS control delay	8	8	t clk
t sac	SS# assertion to first clock edge	6.5	7	t clk
t csd	SS# deassertion from last clock edge	1.5	2	t clk
t op	MOSI propagation time	0	5.8	ns
t oh	MOSI hold time	0.5	0.5	t clk
t is	MISO setup time	4.8	N/A	ns
t ih	MISO hold time	0	N/A	ns
t ud	User Insertable Delay	8	232	tclk