topic LPSPI Chip Select always is LOW (active state) in S32K

LPSPI Chip Select always is LOW (active state)

MVR — Fri, 02 Dec 2022 03:07:36 GMT

Hello,

The chip select is always LOW after we send out the first command, it couldn't be in LOW but must be in HIGH (deactivate state), after finish transmission (in this case, after send the 10 bytes):

I'm using this configuration:

I'm using DMA to TX and RX. The DMA callbacks works well.

I'm using as well this function to transfer data:

Lpspi_Ip_AsyncTransmit();

In Lpspi_Ip_UpdateTransferMode I set with LPSPI_IP_INTERRUPT.

Thanks

Re: LPSPI Chip Select always is LOW (active state)

davidtosenovjan — Fri, 02 Dec 2022 08:38:47 GMT

Could you specify used S32 Design Studio? Also please clarify which MCU you are using.

Re: LPSPI Chip Select always is LOW (active state)

davidtosenovjan — Fri, 02 Dec 2022 09:38:46 GMT

Anyway, at first I would recommend to see following threads:

https://community.nxp.com/t5/S32K/Why-is-CS-pulled-high-before-LPSPI-has-finished-transmitting/td-p/1524086

https://community.nxp.com/t5/S32K/S32K14x-Command-Word-in-LPSPI/td-p/1040779

Re: LPSPI Chip Select always is LOW (active state)

MVR — Fri, 02 Dec 2022 10:58:40 GMT

Ops, I forgot. I'm sorry.

I'm using S32K344 and S32K3 RTD AUTOSAR 4.4 2.0.1 D2207 in S32 Design Studio.

Re: LPSPI Chip Select always is LOW (active state)

MVR — Fri, 02 Dec 2022 18:22:18 GMT

I debugged the code, when we used DMA, the chip select is always LOW (active state):

Base->TCR is never changed, in the other words, Lpspi_Ip_TxDmaFinishTransfer / Lpspi_Ip_TransferProcess are never called.

I initialized the SPI with this way:

Must I use these callbacks in "IntCtrl_Ip_InstallHandler"? The callback "Dma0_Ch1_IRQHandler" have never changed the Chip Select state, but this function notify that the buffer of DMA about SPI is ok and I can use it.

Another information. When I use simple ISR (the callback "Lpspi_Ip_LPSPI_0_IRQHandler"), the Chip select works according, but I would like to use DMA and not ISR. I saw also I can't use both together.

So, summarize, when I use DMA, there is this problem. The sending, receiving and notify callback of DMA are working well, but the chip select is not working.

I'm using this function to send message:

Re: LPSPI Chip Select always is LOW (active state)

MVR — Tue, 06 Dec 2022 12:52:35 GMT

@davidtosenovjan have you ever seen this problem?

Re: LPSPI Chip Select always is LOW (active state)

davidtosenovjan — Wed, 07 Dec 2022 13:05:47 GMT

Could you send me the whole project? I mean the whole example how you have configured it showing mentioned behavior. I will try to debug it or report to software developers if needed. Thanks

Re: LPSPI Chip Select always is LOW (active state)

MVR — Mon, 12 Dec 2022 17:59:20 GMT

Hello @davidtosenovjan

Follow the zip with problem using DMA.

We can see in this code, one example of sending 10 bytes of SPI using DMA, result:

If we test this code without DMA:

We get this result:

Thanks!

Re: LPSPI Chip Select always is LOW (active state)

davidtosenovjan — Fri, 16 Dec 2022 14:44:06 GMT

I just played with this code for quite long time but I haven't found anything wrong.

I guess there is an issue with RTD driver. I will report it and we will see. I will return to you.

Re: LPSPI Chip Select always is LOW (active state)

MVR — Mon, 19 Dec 2022 20:53:52 GMT

Ok David, thanks for the help!

I'm waiting for the answer.

Re: LPSPI Chip Select always is LOW (active state)

davidtosenovjan — Tue, 03 Jan 2023 13:01:09 GMT

I haven't noticed but RTD expert found it out. You have a mistake in your configuration.

As LPSPI instance is 0 so you should put Lpspi_Ip_LPSPI_0_IrqTxDmaHandler in DMA interrupt callback:

Attached modified project.

Re: LPSPI Chip Select always is LOW (active state)

MVR — Tue, 03 Jan 2023 17:41:26 GMT

Ok, but which callback should I use as user callback? Because this "Lpspi_Ip_LPSPI_0_IrqTxDmaHandler" is not available to user, right? I would like to use this callback to do some things.

This "Lpspi_Ip_LPSPI_2_IrqTxDmaHandler" that I defined could be any name, because I'm considering it as an user callback.

Thanks.

Re: LPSPI Chip Select always is LOW (active state)

davidtosenovjan — Fri, 06 Jan 2023 07:48:50 GMT

You can put SPI_Callback to the transmit function calling where you have NULL pointer

I am attaching screenshot from some example code for reference

Re: LPSPI Chip Select always is LOW (active state)

MVR — Thu, 05 Jan 2023 15:36:22 GMT

Nice David, it worked! Thanks