RE: SPI connection with external flash LE25U40CMDTWG

AngeldelaCalle — Fri, 28 Jan 2022 12:39:58 GMT

Hi Sigurd,

thanks for the shared sample. The problem was on the chip select. I was tried to manage it manually and with a logical analyzer I saw that the pin was always high. After initializing it as follows,

struct spi_cs_control spi_cs = {
    .gpio_pin = LE25U40CMDTWG_SPI_CS_PIN,
    .gpio_dt_flags = GPIO_ACTIVE_LOW,
    .delay = 0,
};

void le25u40cmdtwg_init(le25u40cmdtwg_t* le25u40cmdtwg) {
  config = le25u40cmdtwg;

  spi_cs.gpio_dev = device_get_binding(GPIO0_LABEL);
  if (gpio_dev == NULL) {
    LOG_ERR("Could not bind GPIO 0");
    return;
  }
}

the problem is solved and the Rx buffers are filled with the expected values.

RE: SPI connection with external flash LE25U40CMDTWG

Sigurd — Fri, 28 Jan 2022 07:52:32 GMT

Hi,

[quote user=""]Due to the design of the board, I cannot use any external HW as a logical analyzer for testing if the frames are being correctly sent through the MISO/MOSI lines of the spi configuration.[/quote]

You are not able to probe some signals either?

I took a quick look at your code, and I did not spot anything immediately wrong. But I have a simple SPI sample here you can compare with.

Make sure that the external flash is powered and the correct pins are configured.

RE: SPI connection with external flash LE25U40CMDTWG

AngeldelaCalle — Thu, 27 Jan 2022 14:16:00 GMT

I've tried a similar driver based on the nrfx_spi APIs and the behaviour is the same one.

nrfx_spim_xfer(&spim, &xfer_desc, 0) returns NRFX_SUCCESS but the Rx buffer is always empty.

I attach the main part of the source code:

/**
 * INCLUDES
 */

#include "le25u40cmdtwg.h"
#include <logging/log.h>
#include "string.h"
#include "../../hw_config.h"

/**
 * DEFINES
 */

#define MODULE_NAME le25u40cmdtwg
LOG_MODULE_REGISTER(MODULE_NAME, LOG_LEVEL_INF);

static const le25u40cmdtwg_t* config;
const struct device* spi_dev;
static volatile bool spim_xfer_done; /**< Flag used to indicate that SPIM instance completed the transfer. */
static nrfx_spim_config_t spi_config = {.sck_pin = LE25U40CMDTWG_SPI_SCK_PIN,
                                        .mosi_pin = LE25U40CMDTWG_SPI_MOSI_PIN,
                                        .miso_pin = LE25U40CMDTWG_SPI_MISO_PIN,
                                        .ss_pin = LE25U40CMDTWG_SPI_CS_PIN,
                                        .ss_active_high = false,
                                        .irq_priority = NRFX_SPIM_DEFAULT_CONFIG_IRQ_PRIORITY,
                                        .orc = 0xFF,
                                        .frequency = NRF_SPIM_FREQ_1M,
                                        .mode = NRF_SPIM_MODE_3,
                                        .bit_order = NRF_SPIM_BIT_ORDER_MSB_FIRST,
                                        NRFX_SPIM_DEFAULT_EXTENDED_CONFIG};

#define SPI_INSTANCE 3
static const nrfx_spim_t spim = NRFX_SPIM_INSTANCE(SPI_INSTANCE);

// static uint8_t m_rx_buf[sizeof(TEST_STRING) + 1];
// static const uint8_t m_length = sizeof(m_tx_buf);

/**
 * @brief SPI user event handler.
 * @param event
 */
void spim_event_handler(nrfx_spim_evt_t const* p_event, void* p_context) {
  if (p_event->type == NRFX_SPIM_EVENT_DONE) {
    spim_xfer_done = true;
    printk("Transfer completed.");
  }
}

uint8_t le25u40cmdtwg_init(const le25u40cmdtwg_t* le25u40cmdtwg) {
  printk("El init del driver de SPI ya se hace realmente en el main");

  config = le25u40cmdtwg;
  uint8_t ret = 0;

  // Application specific configuration
  if (gpio_pin_configure(config->gpio_dev, LE25U40CMDTWG_SPI_CS_PIN, GPIO_OUTPUT_ACTIVE)) {
    printk("Error while enabling pin %u.", LE25U40CMDTWG_SPI_CS_PIN);
    return -1;
  }

  ret = nrfx_spim_init(&spim, &spi_config, spim_event_handler, NULL);

  /*while (!spim_xfer_done) {
    __WFE();
  }*/

  return ret;
  return 0;
}

uint8_t le25u40cmdtwg_spiTransfer(uint8_t tx_buffer, const le25u40cmdtwg_t* le25u40cmdtwg) {
  nrfx_err_t err_code = 0;

  uint8_t tx[2] = {tx_buffer, 0};  //{0x00 | 0x80, 0};
  uint8_t rx[2] = {0};

  nrfx_spim_xfer_desc_t xfer_desc = {
      .p_tx_buffer = tx,
      .tx_length = 2,
      .p_rx_buffer = rx,
      .rx_length = 2,
  };

  nrf_gpio_pin_clear(LE25U40CMDTWG_SPI_CS_PIN);  // Manual control of the chip select pin

  err_code = nrfx_spim_xfer(&spim, &xfer_desc, 0);

  if (err_code != NRFX_SUCCESS) {
    printk("SPI error: %d\n", err_code);
  }

  nrf_gpio_pin_set(LE25U40CMDTWG_SPI_CS_PIN);

  return rx[1];
}