SPI slave always returns -ETIMEDOUT

[Ubaid_M]

Hi,

I am working on SPI master-slave application, as in, on one BL653 I am running SPI master driver, I am able to observe the waveforms for clock and data transfer from master on USB logic analyzer.

But I am facing an issue with the BL653 board which is running SPI slave code, basically, for slave under main my code is as below:

	m_spi_cfg->operation |= SPI_WORD_SET(8);

	m_rx_bufs->buf = &data;
	m_rx_bufs->len = sizeof(data);

	m_rx_set_buff->buffers = m_rx_bufs;
	m_rx_set_buff->count = 1;

	if ((m_spi_dev) != nullptr)
	{
		l_nStatus = spi_read(m_spi_dev, m_spi_cfg, m_rx_set_buff);
		printk("Received data : %u : %d\n",data,l_nStatus);
		if (l_nStatus != SUCCESS)
		{
			return ERR;
		}
	}

Here spi_read always returns -116, that is  -ETIMEDOUT.

My device binding, spi slave configurations and wiring with spi master are in order.

But I do not understand why slave driver always returns -ETIMEDOUT.

I traced the flow of execution all the way to the source of the error and here is what I found

spi_read( ) -> transceive (in file "spi_nrfx_spis.c") -> spi_context_wait_for_completion( in file "spi_context.h") -> and the source of error is as attached in the below snap in #else part 

Without debug mode as well I am getting the same -ETIMEDOUT.

Kindly suggest on if I have missed out on configuring something.


Thanks,

Ubaid

[Jørgen Holmefjord]

Hi,

Can you try with a different CS pin? P0.01 is by default connected to the 32.768 kHz LF crystal on the nRF52833 DK. The LF clock is usually started by the RTOS, meaning the pin is already in use and cannot be used with the SPI(S) peripheral.

Best regards,
Jørgen

[Ubaid_M]

Hello  Jørgen Holmefjord,

Thanks, for the suggestion 

Jørgen Holmefjord said:

Can you try with a different CS pin?

After cs configuration, I was facing an issue where spi_read( ) was returning  timeout everytime.


With this patch:https://github.com/zephyrproject-rtos/zephyr/pull/39906/commits/dfcc77526163ce6973a5788b202d2a17e4f82d86

I was able to solve this issue, receive & print data on slave board.

But what i do not understand is I cannot have  spi_read( ) wait indefinitely, It is a bad application if so,

Now how can i Optimize this in my application..?
I mean i read data only when it is available & not keep on waiting until data becomes available.

Kindly suggest  Jørgen ,

Thanks,

Ubaid

[Jørgen Holmefjord]

Hi,

I would recommend you to have a look at the discussions in this thread.

Best regards,
Jørgen

[Ubaid_M]

Hello Jørgen Holmefjord,

Thank you for the help.
Please mark this thread as closed