S32KのトピックRe: Communicating with SPI slave driver without using ChipSelect pin

Communicating with SPI slave driver without using ChipSelect pin

jaikumar81 — Fri, 20 Nov 2020 07:53:31 GMT

Hello

We are using custom board S32k148-100 pin for our development activities.

We have a communication requirement to communicate with SPI master(on another chip- exeynos) with SPI slave on S32k148.

We notice that, master is always setting CS(chip select) Pin as high due to which, we are unable to receive any changes on the SPI slave i.e the DMA configured on SPI slave has not triggering DMA complete call back. While on the SPI master (from exeynos) we could see Master clock with 500kbps and data on MOSI line too.

Could you please share the application and changes in the driver required so that LPSPI slave communicates with SPI Master with SPI Slave 3 pins(MOSI, MISO and Clock).

Regards,

Jayakumar Appari

Re: Communicating with SPI slave driver without using ChipSelect pin

danielmartynek — Mon, 23 Nov 2020 11:54:37 GMT

Hi Jayakumar,

The LPSPI module can work as a Slave without PCS if the CFGR1[AUTOPCS] is set.

It has some restrictions as you can see in this description:

BR, Daniel

Re: Communicating with SPI slave driver without using ChipSelect pin

jaikumar81 — Tue, 24 Nov 2020 11:02:20 GMT

Hi Daniel

Thanks for sharing the insights.

Would like to understand, how the below configuration can be synchronized w.r.t master data.

Kindky share your inputs.

Best Regards,

Jayakumar Appari

Re: Communicating with SPI slave driver without using ChipSelect pin

danielmartynek — Wed, 25 Nov 2020 11:16:18 GMT

Hi Jayakumar

You need to configure the master to have the required delay, at least 4 cycles of the prescaled functional clock

Regards,

Daniel

Re: Communicating with SPI slave driver without using ChipSelect pin

jaikumar81 — Wed, 02 Dec 2020 11:24:12 GMT

Thanks Daniel.