NRF52840 UART1 not working in SDK 14

[Jeffrey Haynes]

I'm trying to run two UARTs out of my NRF52840. Do you have an example in which both SoftDevice UARTs are used? The Nordic Infocenter SDK 14.0.0 documentation lists one of the advantages of the new serial port library as multi-instance capability, but there is no example demonstrating such usage.

I started in SDK 12 and wrote my own alternative to app_uart that would allow multiple UART instances. After enabling UART0 and UART1 in the SDK config, I was unable to get both working at the same time. When I initialized a single UART using the board's default TX/RX pins (6 & 8 for pca10056) and NRF_UARTE0 (0x0002000) I was able to see all my serial data come through fine. However, switching to use NRF_UARTE1 (0x40028000) causes the app to crash and restart on attempting to read or write data, despite my using the same pins and configuration parameters as with UART0.

I've seen other questions regarding similar issues, and the general response was that the SDK 14 serial class would resolve this issue. However, I have since downloaded SDK 14 and am seeing the same behavior. I can initialize one UART port with nrf_serial_init, provided the serial port instance uses NRF_UARTE0/NRF_UART0, but again the same parameters do not work with NRF_UARTE1.

[RixtronixLAB]

Is it available on SDK 17

[Jørgen Holmefjord]

There is an example in SDK 16 that shows usage of two UARTE instances with the nrf_serial library in SDK 16.0.0, but this library have been deprecated and removed in SDK 17.0.0. Instead, you should use the libUARTE library, which supports both UARTE instances. See also the Libuarte Example.

[RixtronixLAB]

So far, I can not initialize libuarte for UART0 and UART1, any examples for libuarte for UART0 and UART1, it works for serial uarte...

my complete main.c

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/** @file
 * @defgroup libuarte_example_main main.c
 * @{
 * @ingroup libuarte_example
 * @brief Libuarte Example Application main file.
 *
 * This file contains the source code for a sample application using libuarte.
 *
 */

#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include "nrf_libuarte_async.h"
#include "nrf_drv_clock.h"
#include <bsp.h>
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"
#include "nrf_queue.h"

NRF_LIBUARTE_ASYNC_DEFINE(libuarte, 0, 0, 0, NRF_LIBUARTE_PERIPHERAL_NOT_USED, 255, 3);
NRF_LIBUARTE_ASYNC_DEFINE(libuarte1, 1, 0, 0, NRF_LIBUARTE_PERIPHERAL_NOT_USED, 255, 3);

static uint8_t text[] = "UART example started.\r\n Loopback:\r\n";
static uint8_t text_size = sizeof(text);
uint8_t text_rx[20];

static volatile bool m_loopback_phase;

typedef struct {
    uint8_t * p_data;
    uint32_t length;
} buffer_t;

NRF_QUEUE_DEF(buffer_t, m_buf_queue, 10, NRF_QUEUE_MODE_NO_OVERFLOW);

void uart_event_handler(void * context, nrf_libuarte_async_evt_t * p_evt)
{
    nrf_libuarte_async_t * p_libuarte = (nrf_libuarte_async_t *)context;
    ret_code_t ret;

    switch (p_evt->type)
    {
        case NRF_LIBUARTE_ASYNC_EVT_ERROR:
            bsp_board_led_invert(0);
            break;
        case NRF_LIBUARTE_ASYNC_EVT_RX_DATA:
            ret = nrf_libuarte_async_tx(p_libuarte,p_evt->data.rxtx.p_data, p_evt->data.rxtx.length);
            if (ret == NRF_ERROR_BUSY)
            {
                buffer_t buf = {
                    .p_data = p_evt->data.rxtx.p_data,
                    .length = p_evt->data.rxtx.length,
                };

                ret = nrf_queue_push(&m_buf_queue, &buf);
                APP_ERROR_CHECK(ret);
            }
            else
            {
                APP_ERROR_CHECK(ret);
            }
            bsp_board_led_invert(1);
            m_loopback_phase = true;
            break;
        case NRF_LIBUARTE_ASYNC_EVT_TX_DONE:
            if (m_loopback_phase)
            {
                nrf_libuarte_async_rx_free(p_libuarte, p_evt->data.rxtx.p_data, p_evt->data.rxtx.length);
                if (!nrf_queue_is_empty(&m_buf_queue))
                {
                    buffer_t buf;
                    ret = nrf_queue_pop(&m_buf_queue, &buf);
                    APP_ERROR_CHECK(ret);
                    UNUSED_RETURN_VALUE(nrf_libuarte_async_tx(p_libuarte, buf.p_data, buf.length));
                }
            }
            bsp_board_led_invert(2);
            break;
        default:
            break;
    }
}

void uart_event_handler1(void * context, nrf_libuarte_async_evt_t * p_evt)
{
	NRF_LOG_INFO("UART1 EVENT FROM GPS!\r\n");
}	

/**
 * @brief Function for main application entry.
 */
int main(void)
{
    bsp_board_init(BSP_INIT_LEDS);
    
    ret_code_t ret = nrf_drv_clock_init();
    APP_ERROR_CHECK(ret);
  
    nrf_drv_clock_lfclk_request(NULL);

    ret_code_t err_code = NRF_LOG_INIT(app_timer_cnt_get);
    APP_ERROR_CHECK(err_code);

    NRF_LOG_DEFAULT_BACKENDS_INIT();

    nrf_libuarte_async_config_t nrf_libuarte_async_config = {
            .tx_pin     = TX_PIN_NUMBER,
            .rx_pin     = RX_PIN_NUMBER,
            .baudrate   = NRF_UARTE_BAUDRATE_115200,
            .parity     = NRF_UARTE_PARITY_EXCLUDED,
            .hwfc       = NRF_UARTE_HWFC_DISABLED,
            .timeout_us = 100,
            .int_prio   = APP_IRQ_PRIORITY_LOW
    };
		
		nrf_libuarte_async_config_t nrf_libuarte_async_config1 = {
            .tx_pin     = SER_APP_TX_PIN,
            .rx_pin     = SER_APP_RX_PIN,
            .baudrate   = NRF_UARTE_BAUDRATE_9600,
            .parity     = NRF_UARTE_PARITY_EXCLUDED,
            .hwfc       = NRF_UARTE_HWFC_DISABLED,
            .timeout_us = 100,
            .int_prio   = APP_IRQ_PRIORITY_LOW
    };
		
		
    nrf_libuarte_async_init(&libuarte, &nrf_libuarte_async_config, uart_event_handler, (void *)&libuarte);
		nrf_libuarte_async_init(&libuarte1, &nrf_libuarte_async_config1, uart_event_handler1, (void *)&libuarte1);
    //err_code = nrf_libuarte_async_init(&libuarte, &nrf_libuarte_async_config, uart_event_handler, (void *)&libuarte);
		//err_code = nrf_libuarte_async_init(&libuarte1, &nrf_libuarte_async_config1, uart_event_handler1, (void *)&libuarte1);
		

    APP_ERROR_CHECK(err_code);

    nrf_libuarte_async_enable(&libuarte);
		//nrf_libuarte_async_enable(&libuarte1);

    err_code = nrf_libuarte_async_tx(&libuarte, text, text_size);
		
		//nrf_libuarte_async_rx_free(&libuarte1, text_rx, 20);
    APP_ERROR_CHECK(err_code);

    while (true)
    {
        NRF_LOG_FLUSH();
    }
}


/** @} */

//==========================================================

// <h> nrf_libuarte_drv - libUARTE library

//==========================================================
// <q> NRF_LIBUARTE_DRV_HWFC_ENABLED  - Enable HWFC support in the driver
 

#ifndef NRF_LIBUARTE_DRV_HWFC_ENABLED
#define NRF_LIBUARTE_DRV_HWFC_ENABLED 0
#endif

// <q> NRF_LIBUARTE_DRV_UARTE0  - UARTE0 instance
 

#ifndef NRF_LIBUARTE_DRV_UARTE0
#define NRF_LIBUARTE_DRV_UARTE0 1
#endif

// <q> NRF_LIBUARTE_DRV_UARTE1  - UARTE1 instance
 

#ifndef NRF_LIBUARTE_DRV_UARTE1
#define NRF_LIBUARTE_DRV_UARTE1 1
#endif

// </h> 

[Jørgen Holmefjord]

I see that Jared is helping your out in your other ticket, lets keep this discussion going there.