How do I adjust the timing between slave select and the first clock for SPI frames?

Question from the Customer:

I am using the Promira Serial Platform to communicate on my SPI bus. I want to send SPI frames at 10 MHz and I would like to play with the time between the slave select (SS) line and the first clock (CLK) slope. For example, I want to send the same SPI frame with various SS to CLK times.

Is that possible? How would I do that?

Response from Technical Support:

Thanks for your question! It is possible to customize the timing between the SS and the first CLK slope using the Promira Software API.  The API allows you to configure the SPI timing parameters tSSSCK and tSCKSS by adding the function ps_queue_spi_delay_ns between the functions ps_queue_spi_ss and ps_queue_spi_write.

  • ps_queue_spi_delay_ns: Queues nanoseconds of delay on the bus. The unit of delay that can be queued on the SPI bus is the clock period; the requested delay will be rounded up to this time span. For example, at the bitrate of 10MHz, the size of a single step would be 100ns.
  • ps_queue_spi_ss: Queues the assertion and de-assertion of slave select signals.
  • ps_queue_spi_write:  Queues a command that writes a stream of words to the downstream SPI slave device.

For more information about these and other API functions, please refer to API Documentation in the Promira Serial Platform I2C/SPI Active User Manual. Also, example API programs are available, which you can use as is or modify for your own requirements.

We hope this answers your question. Additional resources that you may find helpful include the following:

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