ESP32 Forum

I am using ESP32-S3 dev board with ESP_IDF v5.1, when running the example code of SPI master with minimum changes (only LCD command set), the program will cause assert failed and then reboot, 100% happen, this is due to ret value is not ESP OK, it said argument problem. But actual code is exactly the example code, not modified. Pls help clarify any bug in the example code or in the v5.1 SPI API library?

this problem happened in non ESP OK return value from the polling_transmitt call and then assert failed then reboot.
example code from spi_master_example_main.c
void lcd_cmd(spi_device_handle_t spi, const uint8_t cmd, bool keep_cs_active)
{
esp_err_t ret;
spi_transaction_t t;
memset(&t, 0, sizeof(t)); //Zero out the transaction
t.length=8; //Command is 8 bits
t.tx_buffer=&cmd; //The data is the cmd itself
t.user=(void*)0; //D/C needs to be set to 0
if (keep_cs_active) {
t.flags = SPI_TRANS_CS_KEEP_ACTIVE; //Keep CS active after data transfer
}
ret=spi_device_polling_transmit(spi, &t); //Transmit!
assert(ret==ESP_OK); //Should have had no issues. ,<<-- reset happen here
}

I am using ESP-IDF v5.1 on ESP32-S3 board, I trace the SPI master example code and finally I found this flag cause the argument problem so ret will not be ESP OK so assert will cause reboot of the system. But how come people can only set false for this cs keep active, and cannot set true for it in the calling to spi_device_polling_transmit()?


if (keep_cs_active) {
t.flags = SPI_TRANS_CS_KEEP_ACTIVE; //Keep CS active after data transfer
}
ret=spi_device_polling_transmit(spi, &t); //Transmit!
assert(ret==ESP_OK); //Should have had no issues.

https://docs.espressif.com/projects/esp ... TickType_t

ESP_ERR_INVALID_ARG if parameter is invalid. This can happen if SPI_TRANS_CS_KEEP_ACTIVE flag is specified while the bus was not acquired (spi_device_acquire_bus() should be called first)