RE: SPI Slave cannot receive data, sending data to master normally

ankushn_14 — Wed, 16 Feb 2022 09:55:15 GMT

Hi Marco, How are you doing?

I am facing the similar issue like you. Were you able to resolve yours?

Below is my code. I am sending 128 bytes of the data and receiving 128 back. I checked from the oscilloscope. Master is sending right data at 1 MHz frequency. But the slave is not receiving. Event_Handler is getting called successfully but the rx buffer is 0 always. Below is my code. It would be really nice if you can help me here.

#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 SPIIF_HW_SYNC_START (0xAABBu)
#define SPIIF_HW_SYNC_END (0x55CCu)

#define SPI_BLOCK_SIZE (118u)

typedef struct
{
uint8_t dummy;
uint8_t sequenceCnt;
uint16_t dataLen;
uint16_t syncStart;
uint8_t dataBuffer[SPI_BLOCK_SIZE];
uint16_t syncEnd
uint16_t dataCrc16;
} SPIIF_SPI_PACKET_T;

SPIIF_SPI_PACKET_T gSpiIfSpiTx __attribute__((aligned(32)));

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

static uint8_t m_tx_buf[sizeof(SPIIF_SPI_PACKET_T)]; /**< TX buffer. */
static uint8_t m_rx_buf[sizeof(SPIIF_SPI_PACKET_T)]; /**< RX buffer. */
static const uint8_t m_length = sizeof(SPIIF_SPI_PACKET_T); /**< 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;
}
}

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;

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;

spis_config.mode = NRF_SPIS_MODE_0;
spis_config.bit_order = NRF_SPIS_BIT_ORDER_MSB_FIRST;
spis_config.csn_pullup = NRFX_SPIS_DEFAULT_CSN_PULLUP;
spis_config.miso_drive = NRFX_SPIS_DEFAULT_MISO_DRIVE;
spis_config.def = NRFX_SPIS_DEFAULT_DEF;
spis_config.orc = NRFX_SPIS_DEFAULT_ORC;
spis_config.irq_priority = NRFX_SPIS_DEFAULT_CONFIG_IRQ_PRIORITY;

gSpiIfSpiTx.dummy = 0u;
gSpiIfSpiTx.dataLen = 0u;
gSpiIfSpiTx.sequenceCnt = 1u;
gSpiIfSpiTx.syncEnd = SPIIF_HW_SYNC_END;
gSpiIfSpiTx.syncStart = SPIIF_HW_SYNC_START;
gSpiIfSpiTx.dataCrc16 = 0u;

for (uint8_t i = 0; i<SPI_BLOCK_SIZE; i++)
{
gSpiIfSpiTx.dataBuffer[i] = 0xAA;
}

nrf_drv_spis_init(&spis, &spis_config, spis_event_handler);

while (1)
{
memcpy(m_tx_buf, &gSpiIfSpiTx, m_length);

spis_xfer_done = false;

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

while (!spis_xfer_done)
{
__WFE();
}
}
}

RE: SPI Slave cannot receive data, sending data to master normally

Jørgen Holmefjord — Tue, 19 Jan 2021 12:58:29 GMT

Hi,

I'm not sure if I understand what you are asking about. What is tx_size set to? If you set the first and last byte of the m_tx_buf array,I would expect you to get something like "AAFFFFF...00000CC", depending on what is in the buffer already.

What are you expecting to receive from the STM?
Have you checked the SPI lines with a logic analyzer, to see if the output is the same that you see in the application?
Are you using the same SPI Mode configuration on both sides?
What frequency is the SPI running at?

You can also possibly try different GPIOs and/or pull, and drive strength configurations for the pins.

Best regards,
Jørgen