RE: SPIS set buffer

MarcoR — Fri, 12 Oct 2018 10:14:14 GMT

I am connecting 2 nrf52832 boards. The SPI master works with the "spi" SDK example.

RE: SPIS set buffer

MarcoR — Fri, 12 Oct 2018 10:06:11 GMT

Thank you haakonsh for your reply.

Starting from the SDK example I deleted the nrf_drv_spis_buffers_set row in while(1) and I made these attempts:

I set the buffers after the initialization:

    NRF_LOG_INFO("SPIS example");

    nrf_drv_spis_config_t spis_config = NRF_DRV_SPIS_DEFAULT_CONFIG;
    spis_config.csn_pin               = APP_SPIS_CS_PIN;
    spis_config.miso_pin              = APP_SPIS_MISO_PIN;
    spis_config.mosi_pin              = APP_SPIS_MOSI_PIN;
    spis_config.sck_pin               = APP_SPIS_SCK_PIN;

    APP_ERROR_CHECK(nrf_drv_spis_init(&spis, &spis_config, spis_event_handler));
	  nrf_drv_spis_buffers_set(&spis, m_tx_buf, m_length, m_rx_buf, m_length);

In this way the SPIS sends correctly only during the fist HITOLO transition of master chip select, then the MISO becomes HIGH and doesn't trasmit data anymore.

I set the buffers also in the spis_event_handler, like in the code below reported:

void spis_event_handler(nrf_drv_spis_event_t event)
{
    if (event.evt_type == NRF_DRV_SPIS_XFER_DONE)
    {
        spis_xfer_done = true;
        NRF_LOG_INFO(" Transfer completed. Received: %s",(uint32_t)m_rx_buf);
				nrf_drv_spis_buffers_set(&spis, m_tx_buf, m_length, m_rx_buf, m_length);
    }
}

In this way the SPIS works fine but I have to recall nrf_drv_spis_buffers_set for every transition.

I didn't change anything also from the example code, I report it for completeness:

/**
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 * All rights reserved.
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 * are permitted provided that the following conditions are met:
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 * 1. Redistributions of source code must retain the above copyright notice, this
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 * 
 * 2. Redistributions in binary form, except as embedded into a Nordic
 *    Semiconductor ASA integrated circuit in a product or a software update for
 *    such product, must reproduce the above copyright notice, this list of
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 *    materials provided with the distribution.
 * 
 * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 * 
 * 4. This software, with or without modification, must only be used with a
 *    Nordic Semiconductor ASA integrated circuit.
 * 
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 */
#include "sdk_config.h"
#include "nrf_drv_spis.h"
#include "nrf_gpio.h"
#include "boards.h"
#include "app_error.h"
#include <string.h>

#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"

#define SPIS_INSTANCE 1 /**< SPIS instance index. */
static const nrf_drv_spis_t spis = NRF_DRV_SPIS_INSTANCE(SPIS_INSTANCE);/**< SPIS instance. */

#define TEST_STRING "Nordic"
static uint8_t       m_tx_buf[] = TEST_STRING;           /**< TX buffer. */
static uint8_t       m_rx_buf[sizeof(TEST_STRING) + 1];    /**< RX buffer. */
static const uint8_t m_length = sizeof(m_tx_buf);        /**< Transfer length. */

static volatile bool spis_xfer_done; /**< Flag used to indicate that SPIS instance completed the transfer. */

/**
 * @brief SPIS user event handler.
 *
 * @param event
 */
void spis_event_handler(nrf_drv_spis_event_t event)
{
    if (event.evt_type == NRF_DRV_SPIS_XFER_DONE)
    {
        spis_xfer_done = true;
        NRF_LOG_INFO(" Transfer completed. Received: %s",(uint32_t)m_rx_buf);
				nrf_drv_spis_buffers_set(&spis, m_tx_buf, m_length, m_rx_buf, m_length);
    }
}

int main(void)
{
    // Enable the constant latency sub power mode to minimize the time it takes
    // for the SPIS peripheral to become active after the CSN line is asserted
    // (when the CPU is in sleep mode).
    NRF_POWER->TASKS_CONSTLAT = 1;

    bsp_board_init(BSP_INIT_LEDS);

    APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
    NRF_LOG_DEFAULT_BACKENDS_INIT();

    NRF_LOG_INFO("SPIS example");

    nrf_drv_spis_config_t spis_config = NRF_DRV_SPIS_DEFAULT_CONFIG;
    spis_config.csn_pin               = APP_SPIS_CS_PIN;
    spis_config.miso_pin              = APP_SPIS_MISO_PIN;
    spis_config.mosi_pin              = APP_SPIS_MOSI_PIN;
    spis_config.sck_pin               = APP_SPIS_SCK_PIN;

    APP_ERROR_CHECK(nrf_drv_spis_init(&spis, &spis_config, spis_event_handler));
	  nrf_drv_spis_buffers_set(&spis, m_tx_buf, m_length, m_rx_buf, m_length);
	  

    while (1)
    {
        memset(m_rx_buf, 0, m_length);
        spis_xfer_done = false;

//        APP_ERROR_CHECK(nrf_drv_spis_buffers_set(&spis, m_tx_buf, m_length, m_rx_buf, m_length));

        while (!spis_xfer_done)
        {
            __WFE();
        }

        NRF_LOG_FLUSH();

        bsp_board_led_invert(BSP_BOARD_LED_0);
    }
}

Did I make any mistake during the initialization?

RE: SPIS set buffer

haakonsh — Fri, 12 Oct 2018 06:28:00 GMT

If you want to re-use your tx/rx buffers then you only need to call nrfx_spis_buffers_set once during initialization. The SPIS will use whatever's in the RXD/TXD registers and it does not reset the register after a transaction is completed.

RE: SPIS set buffer

haakonsh — Fri, 12 Oct 2018 06:27:28 GMT