NRF_SERIAL_EVENT_DRV_ERR, what is the cause?

[RO]

Hi,

I'm trying to receive data from a UART transceiver. I'm using a nRF52 DK with a RS485 to UART transceiver chip.

On my debug session I get the " NRF_SERIAL_EVENT_DRV_ERR" in the serial event handler.

My serial settings are correct because I get correct data on a serial monitor.

I have attached the relevant code:

void init_rs485()
{
	NRF_LOG_DEBUG("init_rs485");
	// Init the Serial UART0 for IPN
	ret_code_t ret;
	ret = nrf_serial_init(&serial1_uart, &m_uart1_drv_config, &serial1_config);
	APP_ERROR_CHECK(ret);
}

void serial_event_handler(struct nrf_serial_s const * p_serial,
		  nrf_serial_event_t event)
{
	ret_code_t ret;
	char c;
	switch (event)
		{
		case NRF_SERIAL_EVENT_TX_DONE:
			break;
		case NRF_SERIAL_EVENT_RX_DATA:
			//NRF_LOG_DEBUG("in serial_event_handler...");
			//Read one char from queue at a time
			do{
				ret = nrf_queue_read(p_serial->p_ctx->p_config->p_queues->p_rxq, &c, sizeof(c));
				if (ret == NRF_SUCCESS) {
					//Echo char back to port
					NRF_LOG_DEBUG("%x ", c);
					ipn_process_event_byte(c);
				}
			} while(ret == NRF_SUCCESS);
			break;
		case NRF_SERIAL_EVENT_DRV_ERR:
			NRF_LOG_ERROR("in serial_event_handler %x", event);
			static uint8_t error_ctr = 0;
			if(error_ctr++ > 5)
				sd_nvic_SystemReset();
			break;
		case NRF_SERIAL_EVENT_FIFO_ERR:
			NRF_LOG_ERROR("in serial_event_handler %x", event);
			break;
		default:
			break;
		}
}

void init_rs485();
void serial_event_handler(struct nrf_serial_s const * p_serial,
		  nrf_serial_event_t event);
void send_rs485_message(char *buffer, size_t length);

// Setup UART0 for IPN
#define IPN_BAUDRATE 0x8A6000
#define UNUSED_PIN 0xFFFFFFFF
#define RS485_TX_PIN     NRF_GPIO_PIN_MAP(0, 6)
#define RS485_RX_PIN     NRF_GPIO_PIN_MAP(0, 5)

NRF_SERIAL_DRV_UART_CONFIG_DEF(m_uart1_drv_config,
					RS485_RX_PIN, RS485_TX_PIN,
					UNUSED_PIN, UNUSED_PIN,
					NRF_UART_HWFC_ENABLED, NRF_UART_PARITY_EXCLUDED,
					IPN_BAUDRATE,
					UART_DEFAULT_CONFIG_IRQ_PRIORITY);

#define SERIAL_FIFO_TX_SIZE 64
#define SERIAL_FIFO_RX_SIZE 64

NRF_SERIAL_QUEUES_DEF(serial1_queues, SERIAL_FIFO_TX_SIZE, SERIAL_FIFO_RX_SIZE);

#define SERIAL_BUFF_TX_SIZE 1
#define SERIAL_BUFF_RX_SIZE 1

NRF_SERIAL_BUFFERS_DEF(serial1_buffs, SERIAL_BUFF_TX_SIZE, SERIAL_BUFF_RX_SIZE);

NRF_SERIAL_CONFIG_DEF(serial1_config, NRF_SERIAL_MODE_DMA,
                      &serial1_queues, &serial1_buffs, serial_event_handler, NULL);

NRF_SERIAL_UART_DEF(serial1_uart, 0);

I also read this question. 

Is this the error mask?

Please help,

Thanks

[bjorn-spockeli]

Hi Ro,

Which SDK version are you using?

According to the nRF52832 Product specification's UART section an error event may be cause by the following:

An ERROR event, in the form of a framing error, will be generated if a valid stop bit is not detected in a frame. Another ERROR event, in the form of a break condition, will be generated if the RXD line is held active low for longer than the length of a data frame. Effectively, a framing error is always generated before a break condition occurs.

You should be able to see the source of the error in the ERRORSRC register, which should be four different bits that are set depending on which error source it is. 

Best regards

Bjørn