Compiling error on compiling form sample "Central uart" using sager

[Mohit Nama]

Hello ,

i have successfully compile and run 'binky' and 'Hello_words  '  sample code using segger .Now i want to test Uart communication with nrf9160 . (want to send string on Tx pin of nrf9160).

for taht i am trying to run sample code "Central uart"  , 

/*
 * Copyright (c) 2018 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
 */

/** @file
 *  @brief Nordic UART Service Client sample
 */

#include <errno.h>
#include <zephyr.h>
#include <sys/byteorder.h>
#include <sys/printk.h>

#include <bluetooth/bluetooth.h>
#include <bluetooth/hci.h>
#include <bluetooth/conn.h>
#include <bluetooth/uuid.h>
#include <bluetooth/gatt.h>

#include <bluetooth/services/nus.h>
#include <bluetooth/services/nus_client.h>
#include <bluetooth/gatt_dm.h>
#include <bluetooth/scan.h>

#include <settings/settings.h>

#include <drivers/uart.h>

#include <logging/log.h>

#define LOG_MODULE_NAME central_uart
LOG_MODULE_REGISTER(LOG_MODULE_NAME);
DEVICE_NAME_GET(central_uart) _CONCAT(nrf9160,central_uart);
/* UART payload buffer element size. */
#define UART_BUF_SIZE 20

#define KEY_PASSKEY_ACCEPT DK_BTN1_MSK
#define KEY_PASSKEY_REJECT DK_BTN2_MSK

#define NUS_WRITE_TIMEOUT K_MSEC(150)
#define UART_WAIT_FOR_BUF_DELAY K_MSEC(50)
#define UART_RX_TIMEOUT 50

static const struct device *uart;
static struct k_work_delayable uart_work;

K_SEM_DEFINE(nus_write_sem, 0, 1);

struct uart_data_t {
	void *fifo_reserved;
	uint8_t  data[UART_BUF_SIZE];
	uint16_t len;
};

static K_FIFO_DEFINE(fifo_uart_tx_data);
static K_FIFO_DEFINE(fifo_uart_rx_data);

static struct bt_conn *default_conn;
static struct bt_nus_client nus_client;

static void ble_data_sent(struct bt_nus_client *nus, uint8_t err,
					const uint8_t *const data, uint16_t len)
{
	ARG_UNUSED(nus);

	struct uart_data_t *buf;

	/* Retrieve buffer context. */
	buf = CONTAINER_OF(data, struct uart_data_t, data);
	k_free(buf);

	k_sem_give(&nus_write_sem);

	if (err) {
		LOG_WRN("ATT error code: 0x%02X", err);
	}
}

static uint8_t ble_data_received(struct bt_nus_client *nus,
						const uint8_t *data, uint16_t len)
{
	ARG_UNUSED(nus);

	int err;

	for (uint16_t pos = 0; pos != len;) {
		struct uart_data_t *tx = k_malloc(sizeof(*tx));

		if (!tx) {
			LOG_WRN("Not able to allocate UART send data buffer");
			return BT_GATT_ITER_CONTINUE;
		}

		/* Keep the last byte of TX buffer for potential LF char. */
		size_t tx_data_size = sizeof(tx->data) - 1;

		if ((len - pos) > tx_data_size) {
			tx->len = tx_data_size;
		} else {
			tx->len = (len - pos);
		}

		memcpy(tx->data, &data[pos], tx->len);

		pos += tx->len;

		/* Append the LF character when the CR character triggered
		 * transmission from the peer.
		 */
		if ((pos == len) && (data[len - 1] == '\r')) {
			tx->data[tx->len] = '\n';
			tx->len++;
		}

		err = uart_tx(uart, tx->data, tx->len, SYS_FOREVER_MS);
		if (err) {
			k_fifo_put(&fifo_uart_tx_data, tx);
		}
	}

	return BT_GATT_ITER_CONTINUE;
}

static void uart_cb(const struct device *dev, struct uart_event *evt, void *user_data)
{
	ARG_UNUSED(dev);

	static uint8_t *current_buf;
	static size_t aborted_len;
	static bool buf_release;
	struct uart_data_t *buf;
	static uint8_t *aborted_buf;

	switch (evt->type) {
	case UART_TX_DONE:
		if ((evt->data.tx.len == 0) ||
		    (!evt->data.tx.buf)) {
			return;
		}

		if (aborted_buf) {
			buf = CONTAINER_OF(aborted_buf, struct uart_data_t,
					   data);
			aborted_buf = NULL;
			aborted_len = 0;
		} else {
			buf = CONTAINER_OF(evt->data.tx.buf,
					   struct uart_data_t,
					   data);
		}

		k_free(buf);

		buf = k_fifo_get(&fifo_uart_tx_data, K_NO_WAIT);
		if (!buf) {
			return;
		}

		if (uart_tx(uart, buf->data, buf->len, SYS_FOREVER_MS)) {
			LOG_WRN("Failed to send data over UART");
		}

		break;

	case UART_RX_RDY:
		buf = CONTAINER_OF(evt->data.rx.buf, struct uart_data_t, data);
		buf->len += evt->data.rx.len;
		buf_release = false;

		if (buf->len == UART_BUF_SIZE) {
			k_fifo_put(&fifo_uart_rx_data, buf);
		} else if ((evt->data.rx.buf[buf->len - 1] == '\n') ||
			  (evt->data.rx.buf[buf->len - 1] == '\r')) {
			k_fifo_put(&fifo_uart_rx_data, buf);
			current_buf = evt->data.rx.buf;
			buf_release = true;
			uart_rx_disable(uart);
		}

		break;

	case UART_RX_DISABLED:
		buf = k_malloc(sizeof(*buf));
		if (buf) {
			buf->len = 0;
		} else {
			LOG_WRN("Not able to allocate UART receive buffer");
			k_work_reschedule(&uart_work, UART_WAIT_FOR_BUF_DELAY);
			return;
		}

		uart_rx_enable(uart, buf->data, sizeof(buf->data),
			       UART_RX_TIMEOUT);

		break;

	case UART_RX_BUF_REQUEST:
		buf = k_malloc(sizeof(*buf));
		if (buf) {
			buf->len = 0;
			uart_rx_buf_rsp(uart, buf->data, sizeof(buf->data));
		} else {
			LOG_WRN("Not able to allocate UART receive buffer");
		}

		break;

	case UART_RX_BUF_RELEASED:
		buf = CONTAINER_OF(evt->data.rx_buf.buf, struct uart_data_t,
				   data);
		if (buf_release && (current_buf != evt->data.rx_buf.buf)) {
			k_free(buf);
			buf_release = false;
			current_buf = NULL;
		}

		break;

	case UART_TX_ABORTED:
			if (!aborted_buf) {
				aborted_buf = (uint8_t *)evt->data.tx.buf;
			}

			aborted_len += evt->data.tx.len;
			buf = CONTAINER_OF(aborted_buf, struct uart_data_t,
					   data);

			uart_tx(uart, &buf->data[aborted_len],
				buf->len - aborted_len, SYS_FOREVER_MS);

		break;

	default:
		break;
	}
}

static void uart_work_handler(struct k_work *item)
{
	struct uart_data_t *buf;

	buf = k_malloc(sizeof(*buf));
	if (buf) {
		buf->len = 0;
	} else {
		LOG_WRN("Not able to allocate UART receive buffer");
		k_work_reschedule(&uart_work, UART_WAIT_FOR_BUF_DELAY);
		return;
	}

	uart_rx_enable(uart, buf->data, sizeof(buf->data), UART_RX_TIMEOUT);
}

static int uart_init(void)
{
	int err;
	struct uart_data_t *rx;

	uart = device_get_binding(DT_LABEL(DT_NODELABEL(uart0)));
	if (!uart) {
		LOG_ERR("UART binding failed");
		return -ENXIO;
	}

	rx = k_malloc(sizeof(*rx));
	if (rx) {
		rx->len = 0;
	} else {
		return -ENOMEM;
	}

	k_work_init_delayable(&uart_work, uart_work_handler);

	err = uart_callback_set(uart, uart_cb, NULL);
	if (err) {
		return err;
	}

	return uart_rx_enable(uart, rx->data, sizeof(rx->data),
			      UART_RX_TIMEOUT);
}

static void discovery_complete(struct bt_gatt_dm *dm,
			       void *context)
{
	struct bt_nus_client *nus = context;
	LOG_INF("Service discovery completed");

	bt_gatt_dm_data_print(dm);

	bt_nus_handles_assign(dm, nus);
	bt_nus_subscribe_receive(nus);

	bt_gatt_dm_data_release(dm);
}

static void discovery_service_not_found(struct bt_conn *conn,
					void *context)
{
	LOG_INF("Service not found");
}

static void discovery_error(struct bt_conn *conn,
			    int err,
			    void *context)
{
	LOG_WRN("Error while discovering GATT database: (%d)", err);
}

struct bt_gatt_dm_cb discovery_cb = {
	.completed         = discovery_complete,
	.service_not_found = discovery_service_not_found,
	.error_found       = discovery_error,
};

static void gatt_discover(struct bt_conn *conn)
{
	int err;

	if (conn != default_conn) {
		return;
	}

	err = bt_gatt_dm_start(conn,
			       BT_UUID_NUS_SERVICE,
			       &discovery_cb,
			       &nus_client);
	if (err) {
		LOG_ERR("could not start the discovery procedure, error "
			"code: %d", err);
	}
}

static void exchange_func(struct bt_conn *conn, uint8_t err, struct bt_gatt_exchange_params *params)
{
	if (!err) {
		LOG_INF("MTU exchange done");
	} else {
		LOG_WRN("MTU exchange failed (err %" PRIu8 ")", err);
	}
}

static void connected(struct bt_conn *conn, uint8_t conn_err)
{
	char addr[BT_ADDR_LE_STR_LEN];
	int err;

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));

	if (conn_err) {
		LOG_INF("Failed to connect to %s (%d)", log_strdup(addr),
			conn_err);

		if (default_conn == conn) {
			bt_conn_unref(default_conn);
			default_conn = NULL;

			err = bt_scan_start(BT_SCAN_TYPE_SCAN_ACTIVE);
			if (err) {
				LOG_ERR("Scanning failed to start (err %d)",
					err);
			}
		}

		return;
	}

	LOG_INF("Connected: %s", log_strdup(addr));

	static struct bt_gatt_exchange_params exchange_params;

	exchange_params.func = exchange_func;
	err = bt_gatt_exchange_mtu(conn, &exchange_params);
	if (err) {
		LOG_WRN("MTU exchange failed (err %d)", err);
	}

	err = bt_conn_set_security(conn, BT_SECURITY_L2);
	if (err) {
		LOG_WRN("Failed to set security: %d", err);

		gatt_discover(conn);
	}

	err = bt_scan_stop();
	if ((!err) && (err != -EALREADY)) {
		LOG_ERR("Stop LE scan failed (err %d)", err);
	}
}

static void disconnected(struct bt_conn *conn, uint8_t reason)
{
	char addr[BT_ADDR_LE_STR_LEN];
	int err;

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));

	LOG_INF("Disconnected: %s (reason %u)", log_strdup(addr),
		reason);

	if (default_conn != conn) {
		return;
	}

	bt_conn_unref(default_conn);
	default_conn = NULL;

	err = bt_scan_start(BT_SCAN_TYPE_SCAN_ACTIVE);
	if (err) {
		LOG_ERR("Scanning failed to start (err %d)",
			err);
	}
}

static void security_changed(struct bt_conn *conn, bt_security_t level,
			     enum bt_security_err err)
{
	char addr[BT_ADDR_LE_STR_LEN];

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));

	if (!err) {
		LOG_INF("Security changed: %s level %u", log_strdup(addr),
			level);
	} else {
		LOG_WRN("Security failed: %s level %u err %d", log_strdup(addr),
			level, err);
	}

	gatt_discover(conn);
}

BT_CONN_CB_DEFINE(conn_callbacks) = {
	.connected = connected,
	.disconnected = disconnected,
	.security_changed = security_changed
};

static void scan_filter_match(struct bt_scan_device_info *device_info,
			      struct bt_scan_filter_match *filter_match,
			      bool connectable)
{
	char addr[BT_ADDR_LE_STR_LEN];

	bt_addr_le_to_str(device_info->recv_info->addr, addr, sizeof(addr));

	LOG_INF("Filters matched. Address: %s connectable: %d",
		log_strdup(addr), connectable);
}

static void scan_connecting_error(struct bt_scan_device_info *device_info)
{
	LOG_WRN("Connecting failed");
}

static void scan_connecting(struct bt_scan_device_info *device_info,
			    struct bt_conn *conn)
{
	default_conn = bt_conn_ref(conn);
}

static int nus_client_init(void)
{
	int err;
	struct bt_nus_client_init_param init = {
		.cb = {
			.received = ble_data_received,
			.sent = ble_data_sent,
		}
	};

	err = bt_nus_client_init(&nus_client, &init);
	if (err) {
		LOG_ERR("NUS Client initialization failed (err %d)", err);
		return err;
	}

	LOG_INF("NUS Client module initialized");
	return err;
}

BT_SCAN_CB_INIT(scan_cb, scan_filter_match, NULL,
		scan_connecting_error, scan_connecting);

static int scan_init(void)
{
	int err;
	struct bt_scan_init_param scan_init = {
		.connect_if_match = 1,
	};

	bt_scan_init(&scan_init);
	bt_scan_cb_register(&scan_cb);

	err = bt_scan_filter_add(BT_SCAN_FILTER_TYPE_UUID, BT_UUID_NUS_SERVICE);
	if (err) {
		LOG_ERR("Scanning filters cannot be set (err %d)", err);
		return err;
	}

	err = bt_scan_filter_enable(BT_SCAN_UUID_FILTER, false);
	if (err) {
		LOG_ERR("Filters cannot be turned on (err %d)", err);
		return err;
	}

	LOG_INF("Scan module initialized");
	return err;
}


static void auth_cancel(struct bt_conn *conn)
{
	char addr[BT_ADDR_LE_STR_LEN];

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));

	LOG_INF("Pairing cancelled: %s", log_strdup(addr));
}


static void pairing_complete(struct bt_conn *conn, bool bonded)
{
	char addr[BT_ADDR_LE_STR_LEN];

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));

	LOG_INF("Pairing completed: %s, bonded: %d", log_strdup(addr),
		bonded);
}


static void pairing_failed(struct bt_conn *conn, enum bt_security_err reason)
{
	char addr[BT_ADDR_LE_STR_LEN];

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));

	LOG_WRN("Pairing failed conn: %s, reason %d", log_strdup(addr),
		reason);
}

static struct bt_conn_auth_cb conn_auth_callbacks = {
	.cancel = auth_cancel,
	.pairing_complete = pairing_complete,
	.pairing_failed = pairing_failed
};

void main(void)
{
	int err;

	err = bt_conn_auth_cb_register(&conn_auth_callbacks);
	if (err) {
		LOG_ERR("Failed to register authorization callbacks.");
		return;
	}

	err = bt_enable(NULL);
	if (err) {
		LOG_ERR("Bluetooth init failed (err %d)", err);
		return;
	}
	LOG_INF("Bluetooth initialized");

	if (IS_ENABLED(CONFIG_SETTINGS)) {
		settings_load();
	}

	int (*module_init[])(void) = {uart_init, scan_init, nus_client_init};
	for (size_t i = 0; i < ARRAY_SIZE(module_init); i++) {
		err = (*module_init[i])();
		if (err) {
			return;
		}
	}

	printk("Starting Bluetooth Central UART example\n");


	err = bt_scan_start(BT_SCAN_TYPE_SCAN_ACTIVE);
	if (err) {
		LOG_ERR("Scanning failed to start (err %d)", err);
		return;
	}

	LOG_INF("Scanning successfully started");

	for (;;) {
		/* Wait indefinitely for data to be sent over Bluetooth */
		struct uart_data_t *buf = k_fifo_get(&fifo_uart_rx_data,
						     K_FOREVER);

		err = bt_nus_client_send(&nus_client, buf->data, buf->len);
		if (err) {
			LOG_WRN("Failed to send data over BLE connection"
				"(err %d)", err);
		}

		err = k_sem_take(&nus_write_sem, NUS_WRITE_TIMEOUT);
		if (err) {
			LOG_WRN("NUS send timeout");
		}
	}
}

on build this , ERROR;   unknown type name '__device_central_uart'

when i click on error ik took me to "deceive.h" file     following funtion. 

#define DEVICE_NAME_GET(name) _CONCAT(__device_, name)

[Hung Bui]

Hi Mohit, 

The central_uart is not made for the nRF9160. It requires the device to have Bluetooth which nRF91 doesn't. The main purpose of the application is to convert BLE data to send to UART and vice versa. 

If you want  to test UART, please have a look at this thread, our coworker Stian have made an example of using UART with nRF91: 
https://devzone.nordicsemi.com/f/nordic-q-a/77273/basic-uart-sample-for-nrf-connect-sdk

[Mohit Nama]

sir , 

i have tried 

#include <zephyr.h>
#include <device.h>
#include <devicetree.h>
#include <drivers/uart.h>

static uint8_t uart_buf[1024];

void uart_cb(const struct device *x, void *user_data)
{
	uart_irq_update(x);
	int data_length = 0;

	if (uart_irq_rx_ready(x)) {
		data_length = uart_fifo_read(x, uart_buf, sizeof(uart_buf));
		uart_buf[data_length] = 0;
	}
    uart_fifo_fill(x, uart_buf, data_length);
}

void main(void)
{

    const struct device *uart = device_get_binding("UART_2");
	uart_irq_callback_set(uart, uart_cb);
	uart_irq_rx_enable(uart);
	uart_fifo_fill(uart, "UART loopback start!\r\n", 22);
	printk("UART loopback start!\n"); //output on UART0, which is default for logging
	while (1) {
		k_cpu_idle();
	}
}

this code from given project file by you, 

program is successfully uploaded but , don't reviled any data on pin TX i have tried all pin but not get data.    

[Hung Bui]

Hi,

Have you tried with the example .zip file provided by Stian ? You would need to have the overlay file as described. 

[Mohit Nama]

yes sir , 

can you suggest Exact Tx pin for check output, I have confusion regards.

i usually is used "real term " for check uart data using USB to TTL converter (for,Nuvoton,and arduino based projects)    

[Hung Bui]

Hi Mohit, 
If you look at Stian answer you can see that the UART pin is configured as P0.30 and P0.31: 

 Note that these pins are not connected to the interface MCU (so you can't use Real term to get the data right from the USB port of the DK). You can use a scope or connect to another MCU to get the UART data (or do a loop back). 

If you want to use the virtual COM port created by the interface MCU you would need to use uart0 instead. 

When you tested with Helloworld example, do you see the output on the virtual COMport ? 

[Mohit Nama]

okay thanks for quick response