SPI doesnot work on nRF52832

Question

Hi,

I'm trying to use the nrf52832 as the SPI master to get read/write flash ic MX25L6433FM2I-08G(address - 0x00 to 0xFF).

In loopback case got data but when interfacing actual flash ic not get data. Got output as :

<info> app: Transfer completed.

<info> app: Received:

<info> app: FF FF FF FF FF FF FF |.......

I'm using nRF5_SDK_17.0.2_d674dde\examples\peripheral\spi\pca10040 (please find below code)

#include "nrf_drv_spi.h"
#include "app_util_platform.h"
#include "nrf_gpio.h"
#include "nrf_delay.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 SPI_INSTANCE 0 /**< SPI instance index. */
static const nrf_drv_spi_t spi = NRF_DRV_SPI_INSTANCE(SPI_INSTANCE); /**< SPI instance. */
static volatile bool spi_xfer_done; /**< Flag used to indicate that SPI instance completed the transfer. */

#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. */

/**
* @brief SPI user event handler.
* @param event
*/
void spi_event_handler(nrf_drv_spi_evt_t const * p_event,
void * p_context)
{
spi_xfer_done = true;
NRF_LOG_INFO("Transfer completed.\r\n");
SEGGER_RTT_WriteString(0, "SPI transfer completed!\n");
if (m_rx_buf[0] != 0)
{
NRF_LOG_INFO(" Received:\r\n");
SEGGER_RTT_WriteString(0, "SPI received!\n");
NRF_LOG_HEXDUMP_INFO(m_rx_buf, strlen((const char *)m_rx_buf));
}
}

int main(void)
{
bsp_board_init(BSP_INIT_LEDS);

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

uint8_t adress=0x00; //The adress of the INFO register
uint8_t message= (adress<<1)+1; //Add the Read(1)/Write(0) command
m_tx_buf[0]=message;

nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;
spi_config.ss_pin = SPI_SS_PIN; //31
spi_config.miso_pin = SPI_MISO_PIN; //30
spi_config.mosi_pin = SPI_MOSI_PIN; //29
spi_config.sck_pin = SPI_SCK_PIN; //26
APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, spi_event_handler, NULL));

NRF_LOG_INFO("SPI example started.");

while (1)
{
// Reset rx buffer and transfer done flag
memset(m_rx_buf, 0, m_length);
spi_xfer_done = false;

APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_buf, m_length, m_rx_buf, m_length));

while (!spi_xfer_done)
{
__WFE();
}

NRF_LOG_FLUSH();

bsp_board_led_invert(BSP_BOARD_LED_0);
nrf_delay_ms(200);
}
}

Kindly suggest solution as soon as possible if any. Waiting for reply

MeghaC · Accepted Answer

Hi, 
 SPI works fine after following sequences as per MX25L6433FM2I-08G datasheet.

hmolesworth · Answer

The default config you are using is 4MHz, which is probably too fast for the default drive levels. Start by boosting the output signal drive levels; later you can try reducing them but not until you get the SPI working. Do it like this: 
 // Init SPI first then set High Drive level 0 and 1 (something like this):
APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, spi_event_handler, NULL));

// Now boost drive to pins MOSI and CLK and CS to sharpen clock edges and timing
nrf_gpio_cfg(SPI_MOSI_PIN, NRF_GPIO_PIN_DIR_OUTPUT, NRF_GPIO_PIN_INPUT_CONNECT, NRF_GPIO_PIN_NOPULL, NRF_GPIO_PIN_H0H1, NRF_GPIO_PIN_NOSENSE);
nrf_gpio_cfg(SPI_SCK_PIN, NRF_GPIO_PIN_DIR_OUTPUT, NRF_GPIO_PIN_INPUT_CONNECT, NRF_GPIO_PIN_NOPULL, NRF_GPIO_PIN_H0H1, NRF_GPIO_PIN_NOSENSE);
nrf_gpio_cfg(SPI_SS_PIN, NRF_GPIO_PIN_DIR_OUTPUT, NRF_GPIO_PIN_INPUT_CONNECT, NRF_GPIO_PIN_NOPULL, NRF_GPIO_PIN_H0H1, NRF_GPIO_PIN_NOSENSE);
 
 Refer to my post spi-not-operating-correctly for more details. 
 Edit: You are using 0x01 command code, which is a NOP (nothing); try 0x9F which is a whoami 
 Try this: 
 m_tx_buf[0]=0x9F; // Read Id, should respond 0xC2 0x20 0x17 or similar

SPI doesnot work on nRF52832

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