Question from the Customer:
I have been using the Cheetah SPI Host Adapter for years, and it has always worked for me. But today, I have a setup that is giving me some problems. I’m testing a new SPI device and I need to send more than 8 bits per packet. If there is any delay within that stream, such as clock stoppage every 8 bits, communicating with that device fails. The data must be sent as 32-bit words. How can I send 32-bit words using the Cheetah adapter?
Response from Technical Support:Thanks for your question! For your system requirements, we recommend the Promira Serial Platform with the appropriate level of SPI Active application: Level 1, Level 2, or Level 3. The Promira platform is the only SPI adapter that can perform the function you’re looking for. The Cheetah adapter can provide 16-bit data transactions with no delays, but it does not support the full range of word sizes that you need.
How to Use the Promira Serial Platform for Various Word Lengths
To vary the word lengths, you will be using Promira Software API, which supports multiple operating systems and several programming languages. Also, example programs are provided that can be used as-is or modified for your specifications.
The Word Lengths the Promira Platform Supports and How
For the Promira platform, the word size can be set from 2 bits to 32 bits without the “clock stopping” inter-byte delay.
For your usage, the API command ps_queue_spi_write should work. The argument includes the parameter word_size that can be used to specify the packet length of each burst.
Here are details about this API command that writes a stream of words to the downstream SPI slave device:
int ps_queue_spi_write (PromiraQueueHandle queue,PromiraSpiIOMode io,
u08 word_size,
u32 out_num_words,
const u08 * data_out);
For more information about API commands, please refer to the API Documentation section of the Promira Serial Platform I2C/SPI Active User Manual
Additional resources that you may find helpful include the following:
- Promira Serial Platform I2C/SPI Active User Manual
- Promira Serial Platform System User Manual
- Cheetah SPI Host Adapter User Manual
We hope this answers your questions. If you have other questions about our software, host adapters or other Total Phase products, feel free to email us at sales@totalphase.com. You can also request a demo that is specific for your application