topic whether S32K1 SDK3.0 LPSPI_SetFlushFifoCmd function will push LPSPI fifo data to spi bus in S32K

whether S32K1 SDK3.0 LPSPI_SetFlushFifoCmd function will push LPSPI fifo data to spi bus

teddywang — Sat, 18 May 2024 03:30:28 GMT

hi all

1:I use S32K146 ' LPSPI interrupt mode to communicate FS4503,I found 2 words send in one CS period sometimes,

2:I checked S32K1 SDK3.0 source code,I found the LPSPI use 2 times LPSPI_SetFlushFifoCmd (),the code comments is that " The second flush command is used to avoid the case when one word is still in shifter"

3:I want to be sure whether the second flush command will push no use data in fifo to spi bus,then bus will appear twice data

4:If yes,how to work around,thanks

/* Clean RX and TX buffers */
LPSPI_SetFlushFifoCmd(base, true, true);
/* The second flush command is used to avoid the case when one word is still in shifter. */
LPSPI_SetFlushFifoCmd(base, true, true);

Re: whether S32K1 SDK3.0 LPSPI_SetFlushFifoCmd function will push LPSPI fifo data to spi bus

frank_yang_1_offboarding — Wed, 29 May 2024 09:10:51 GMT

Hi Wang,

After test, the operations of RRF and RTF will not push unused data to SPI bus.

These are internal hardware IP operations that will not affect the SPI bus.

Frank

Re: whether S32K1 SDK3.0 LPSPI_SetFlushFifoCmd function will push LPSPI fifo data to spi bus

zhijian — Mon, 03 Jun 2024 08:19:08 GMT

hi,Frank

Plase reference attachment,Thanks!

Re: whether S32K1 SDK3.0 LPSPI_SetFlushFifoCmd function will push LPSPI fifo data to spi bus

frank_yang_1_offboarding — Thu, 06 Jun 2024 08:02:25 GMT

Hi zhijian,

How about the latest status based on given advice? In myside, I could not re-produce this issue until now.

A little advice, we suggest that setting GPIO PCS line in SPI ISR with you using SPI under interrupt mode.

Frank