Trigger LPSPI message every 300us periodically without CPU intervention

[sambath_kumar_k]

I am using S32k146.
what I need: Need to send 8 different SPI messages to slave periodically every 300us without CPU intervention. I found PIT can trigger SPI and SPI can trigger DMA for transfers of SOurce and results. 
Whereas I see some problem on, When the SPI will request to DMA transfer and how to do this periodically without CPU intervention.
Have anyone got the same design ?
#lpspi‌#s32k144 lpspi dma crc demo‌

[danielmartynek]

Hi sambath_kumar_kardhik@cat.com,

What do you mean by PIT can trigger SPI?

The LPSPI module has an input trigger, but there have to be same data in the TX FIFO at the time the trigger is asserted.

LPSPI can request a DMA transfer when there are new data received [RDF = 1] or the TX FIFO is empty [TDF = 1].

LPIT can trigger DMA directly to transfer data to the LPSPI TX FIFO and start an LPSPI transfer.

A simple example is here:

https://community.nxp.com/docs/DOC-346587 

BR, Daniel