RE: How to update SPIM TXD.PTR/RXD.PTR safely?

squwal — Thu, 04 Mar 2021 02:58:19 GMT

Thank you Jorgen, everything goes well now!

RE: How to update SPIM TXD.PTR/RXD.PTR safely?

Jørgen Holmefjord — Tue, 02 Mar 2021 15:26:29 GMT

Hi,

It should be safe to update the pointers between a END event and triggering of the START task. It is not fully clear from the posted code snippets how you handle this transition. Is this handled by the default IRQ handler in the driver, or do you handle it manually in your application?

You may need to temporarily pause the triggering of the START task while updating the pointers to make sure you can update the pointer safely. One possible way to do this is to use a PPI channel to automatically trigger the START task on reception of the END event, and concurrently count the number of generated END events from the SPIM using a TIMER in count mode. You can then use COMPARE event from this counter to disable to PPI channel that triggers the SPIM START task when you have reached the number og available buffers, and at the same time trigger an interrupt that is used to update the buffer pointers (instead of using the 1.5s timer interrupt for this).

Best regards,
Jørgen