S32 SDKのトピックRe: LPSPI and EDMA setting issue for the callback function

LPSPI and EDMA setting issue for the callback function

linton — Sun, 28 Apr 2024 09:33:01 GMT

I am setting the SPI with S32DS configure tool, when I select the Transfer type DMA, and the Callback function is the SPI sent complete or the EDMA sent complete callback?? if this is the SPI transfer complete callback, Where to set the EDMA transfer complete callback? anybody know are there any doc for reference? I am confuse, Thanks

Re: LPSPI and EDMA setting issue for the callback function

danielmartynek — Mon, 29 Apr 2024 12:15:47 GMT

Hello @linton,

You did not specify the MCU and the SDK version.

But this is a callback of the LPSPI driver.

The documentation of the driver can be accessed from the IDE

Right-click on the driver -> Documentation.

Regards,

Daniel

Re: LPSPI and EDMA setting issue for the callback function

linton — Tue, 30 Apr 2024 01:04:54 GMT

Thanks Daniel,

I check the relay doc you recommend, but still not clear.

the MCU I use is the S32K148_LQFP100, the SDK version is s32sdk_s32k1xx_rtm_401

Re: LPSPI and EDMA setting issue for the callback function

danielmartynek — Tue, 30 Apr 2024 11:00:51 GMT

There is no other documentation for the drivers.

What issues fo you have with the callback?

The LPSPI driver should call the callback at the end of the transfer.

There is this SPI event defined in callbacks.h

Regards,

Daniel

Re: LPSPI and EDMA setting issue for the callback function

linton — Wed, 08 May 2024 03:36:16 GMT

Hi daniel,

I set the LPSPI_0 as below photo show:

and I use the scope to test the SOUT waveform as below show:

I send 20 bytes data, so I can calculate the baudrate is about 4.2M(what I set is 4.8M), and I check the clock is right. as below show:

what cause this problem? what I need is 4.8M , 4.75 to 4.85 is acceptable. but 4.2M is bad.

the second problem is I change the transfer type from DMA to interrupt. the configure as below:

and I also use the scope to test the SOUT waveform as below show:

as you can see it separate my 20bytes data to five part, 4 bytes per part. What cause this problem?

Re: LPSPI and EDMA setting issue for the callback function

danielmartynek — Fri, 10 May 2024 07:00:33 GMT

Hi @linton,

The baudrate is calculated by the RTD driver from the LPSPI clock.

RM, 51.3.1.12 Clock Configuration Register (CCR).

Can you try using a higher freq. LPSPI clock?

It is expected to see some overhead when the interrupt mode is used, the LPSPI module has 4-word TX FIFO.

Regards,

Daniel

Re: LPSPI and EDMA setting issue for the callback function

linton — Sun, 12 May 2024 13:13:09 GMT

Hi Daniel,

now I use the higher freq(56MHZ) as below show:

but the performance did not looks better than before, it still separate to five parts(4bytes per part):

the blue is using interrupt, the green is using DMA.

are there any solution to solve this issue when I use the interrupt mode??

my application is simple as below show:

Re: LPSPI and EDMA setting issue for the callback function

danielmartynek — Mon, 13 May 2024 05:45:36 GMT

Hello @linton,

This is simply a limitation of the driver.

In general, the SDK drivers are big and cause some CPU overhead.

Enabling the cache could somewhat help but not much.

Regards,

Daniel

Re: LPSPI and EDMA setting issue for the callback function

linton — Mon, 13 May 2024 05:58:17 GMT

so to avoid this issue, I should not use the SDK interface, directly control the TDR??

Re: LPSPI and EDMA setting issue for the callback function

danielmartynek — Mon, 13 May 2024 07:58:04 GMT

Yes, that would be much more effective.

If the TX FIFO is written before the LPSPI module shifts the last word, there will be no gap between the frames.

BR, Daniel