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 share the rest of the source code, and your prj.conf file?

Where are you calling the spi_read() function?

Are the CSN pin connected and toggling as expected?

Best regards,
Jørgen

[Ubaid_M]

Hello Jørgen Holmefjord,

Jørgen Holmefjord said:

Are the CSN pin connected and toggling as expected?

I have uploaded the code and csn pin states on a logic analyser in the case:

https://devzone.nordicsemi.com/f/nordic-q-a/83616/using-spi_write-spi_read-not-behaving-the-same-as-spi_transceive-for-spi-data-in-provided-spi-sample

Same problem yet, 

I have tried everything, yet no progress, can you kindly help out on why I am unable to receive data on slave board.


Thanks,

Ubaid

[Ubaid_M]

Hello   Jørgen Holmefjord,

Clearly master board it is doing, I think something with slave board or slave pin out config.


Can you have a look at slave code, config and kindlu suggest, as in below.
 

SLAVE:************************************

I am using  second board to run as a Slave, an nrf52833_dk,
It's project is as follows:

Code:

/*
 * Copyright (c) 2012-2014 Wind River Systems, Inc.
 *
 * SPDX-License-Identifier: Apache-2.0
 */
#include <string.h>
#include <errno.h>
#include <zephyr.h>
#include <sys/printk.h>
#include <device.h>
#include <drivers/spi.h>


/*---------------------------------------------------------------------------*/
/*                                                                           */
/*---------------------------------------------------------------------------*/

#define SPI_SLAVE_BUS_NAME     			DT_INST_0_NORDIC_NRF_SPIS_LABEL
#define SPI_SLAVE_GPIOS_NAME    		DT_ALIAS_GPIO_0_LABEL
#define SPI_SLAVE_GPIO_IRQ_PIN  		DT_ALIAS_SPI_0_CSN_PIN

#define STACKSIZE 1024
#define PRIORITY 99

/*---------------------------------------------------------------------------*/
/*                                                                           */
/*---------------------------------------------------------------------------*/
void spi_slave_init(void);

/*---------------------------------------------------------------------------*/
/*                                                                           */
/*---------------------------------------------------------------------------*/
int spi_slave_write(struct device * spi, 
                    struct spi_config * spi_cfg,
                    uint16_t * data)
{
    struct spi_buf bufs = {
            .buf = data,
            .len = 2
    };
    struct spi_buf_set tx = {
        .buffers = &bufs
    };
    
    tx.count = 1;

    return spi_write(spi, spi_cfg, &tx);
}

/*---------------------------------------------------------------------------*/
/*                                                                           */
/*---------------------------------------------------------------------------*/
int spi_slave_read(struct device * spi, 
                   struct spi_config * spi_cfg,
                   uint16_t * data)
{
    struct spi_buf bufs = {
            .buf = data,
            .len = 2
    };
    struct spi_buf_set rx = {
        .buffers = &bufs
    };
    
    rx.count = 1;

    return spi_read(spi, spi_cfg, &rx);
}

/*---------------------------------------------------------------------------*/
/*                                                                           */
/*---------------------------------------------------------------------------*/
void spi_slave_init(void)
{
    struct device * spi;
    struct spi_config spi_cfg;

    uint16_t tx_data = 0x5678;
    uint16_t rx_data = 0;

    printk("SPI Slave example application\n");

    printk("rx_data buffer at %p\n", &rx_data);

    spi = device_get_binding("SPI_0");
    if (!spi) {
        printk("Could not find SPI driver\n");
        return;
    }

    /*
     *  SPI controller configuration structure for the nRF52 series.
     *
     *  param frequency is the bus frequency in hertz
     *  param operation is a bit field with the following parts:
     *
     *     operational mode  [ 0 ]       - master or slave.
     *     mode              [ 1 : 3 ]   - Polarity, phase and loop mode.
     *     transfer          [ 4 ]       - LSB or MSB first.
     *     word_size         [ 5 : 10 ]  - Size of a data frame in bits.
     *     lines             [ 11 : 12 ] - MISO lines: Single/Dual/Quad/Octal.
     *     cs_hold           [ 13 ]      - Hold on the CS line if possible.
     *     lock_on           [ 14 ]      - Keep resource locked for the caller.
     *     cs_active_high    [ 15 ]      - Active high CS logic.
     *
     *  param slave is the slave number from 0 to host controller slave limit.
     *  param cs is a valid pointer on a struct spi_cs_control is CS line is
     *        emulated through a gpio line, or NULL otherwise.
     */

    /* Note: Implicid Mode-0; e.g. CPOL=0, CPHA=0 -- the only mode supported */
    /* Note: The nRF52 series doesn't support CS pin configuration */

    memset(&spi_cfg, 0, sizeof(spi_cfg));

    spi_cfg.operation = SPI_WORD_SET(8) | SPI_OP_MODE_SLAVE;
    spi_cfg.frequency = 1000000;
    spi_cfg.slave = 1;

    printk("%s: slave config @ %p:"
            " wordsize(%u), mode(%u/%u/%u)\n", __func__, &spi_cfg,
            SPI_WORD_SIZE_GET(spi_cfg.operation),
            (SPI_MODE_GET(spi_cfg.operation) & SPI_MODE_CPOL) ? 1 : 0,
            (SPI_MODE_GET(spi_cfg.operation) & SPI_MODE_CPHA) ? 1 : 0,
            (SPI_MODE_GET(spi_cfg.operation) & SPI_MODE_LOOP) ? 1 : 0);

    while (1) {
        spi_slave_read(spi, &spi_cfg, &rx_data);

        if (rx_data == 0x1234) {
            spi_slave_write(spi, &spi_cfg, &tx_data);
        }
        printk("Received: 0x%04X -- %s\n", rx_data,
               (rx_data == 0x1234) ? "ok" : "wrong"); 
    }
}


/*---------------------------------------------------------------------------*/
/*                                                                           */
/*---------------------------------------------------------------------------*/
void spi_slave_thread(void * id, void * unused1, void * unused2)
{
    printk("%s\n", __func__);

    spi_slave_init();

    while (1) { /* spin */}
}

K_THREAD_DEFINE(spi_slave_id, STACKSIZE, spi_slave_thread, 
                NULL, NULL, NULL, PRIORITY, 0, 0);

nrf52833dk_nrf52833.overlay:

/*

* Copyright (c) 2019 Callender-Consulting, LLC

*

* SPDX-License-Identifier: Apache-2.0

*/

&spi0 {

compatible = "nordic,nrf-spis";

status = "okay";

sck-pin = <27>;

mosi-pin = <26>;

miso-pin = <29>;

csn-pin = <1>;

def-char = <0xFF>;

};

prj.conf:

# nothing here

CONFIG_DEBUG=y

CONFIG_GPIO=y

CONFIG_SPI=y

CONFIG_SPI_SLAVE=y

CONFIG_PRINTK=y

Hardware connections:

SCLK : M-41 : S-27
MOSI : M-40 : S-26

MISO : M-04 : S-29

CS :     M-23 : S-1


Kindly suggest where i can look for further, I have evaluated everything yet to no avail 

Thanks