Solved
STM32U5 SPI Slave Not Working Zephyr
Hi all,
I'm struggling to get SPI working on my STM32U5G9J. I have an nordic master device outputting 6 bytes of data every 500 ms over SPI and plugged into the proper pins, double checked and confirmed on analyzer.
stm32u5g9j_dk2.overlay
/ {
aliases {
spi-slave = &spi1;
};
};
&spi1 {
status = "okay";
pinctrl-0 = <&spi1_sck_pa5 &spi1_miso_pa6 &spi1_mosi_pb5 &spi1_nss_pb0>;
pinctrl-names = "default";
/delete-property/ cs-gpios;
fifo-enable;
};main.c
#include <zephyr/kernel.h>
#include <zephyr/logging/log.h>
#include <zephyr/drivers/spi.h>
#include <zephyr/drivers/gpio.h>
#include <zephyr/sys/util.h>
LOG_MODULE_REGISTER(main);
#define SPIOP (SPI_OP_MODE_SLAVE | SPI_WORD_SET(8) | SPI_LINES_SINGLE | SPI_TRANSFER_MSB)
static const struct device *spi_in_dev = DEVICE_DT_GET(DT_ALIAS(spi_slave));
static const struct spi_config spi_in_cfg = {
.frequency = MHZ(1),
.operation = SPIOP,
.slave = 0,
};
int main(void)
{
if (!device_is_ready(spi_in_dev))
{
LOG_ERR("SPI not ready");
return 1;
}
LOG_INF("program started");
static uint8_t rx_buf[1];
static const size_t rx_size = sizeof(rx_buf);
static struct spi_buf rx_spi_buf = {.buf = rx_buf, .len = rx_size};
static struct spi_buf_set rx_spi_buf_set = {.buffers = &rx_spi_buf, .count = 1};
while (1)
{
memset(rx_buf, 0, rx_size);
int ret = spi_read(spi_in_dev, &spi_in_cfg, &rx_spi_buf_set);
if (ret < 0)
{
LOG_ERR("SPI read error: %d", ret);
continue;
}
LOG_HEXDUMP_INF(rx_buf, rx_size, "read bytes:");
}
return 0;
}prj.conf
CONFIG_SPI=y
CONFIG_GPIO=y
CONFIG_PINCTRL=y
CONFIG_SPI_SLAVE=y
CONFIG_SPI_STM32_INTERRUPT=y
CONFIG_LOG=y
CONFIG_LOG_MODE_IMMEDIATE=y
It's logging every 500 ms (exactly when master outputs data):
<err> spi_stm32: spi_stm32_get_err: err=32
<err> main: SPI read error: -5
err 32 (hex 0x20) is generic HAL_SPI_ERROR_FLAG. If I disconnect the MOSI pin the error persists; Disconnecting any other pins stops prints.
The error seems to be here, called during spi interrupt:
static int spi_stm32_get_err(SPI_TypeDef *spi)
{
uint32_t sr = stm32_reg_read(&spi->SR);
if ((sr & SPI_STM32_ERR_MSK) != 0U) {
LOG_ERR("%s: err=%d", __func__, sr & (uint32_t)SPI_STM32_ERR_MSK);
/* OVR error must be explicitly cleared */
if (LL_SPI_IsActiveFlag_OVR(spi)) {
LL_SPI_ClearFlag_OVR(spi);
}
return -EIO;
}
return 0;
}I'm not really sure where to go from here in debugging. Any suggestions?
Thanks.