main.c

/*
 * Copyright (c) 2016 Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 */

/**
 * @file
 * @brief Sample app for CDC ACM class driver
 *
 * Sample app for USB CDC ACM class driver. The received data is echoed back
 * to the serial port.
 */

#include <stdio.h>
#include <string.h>
#include <device.h>
#include <uart.h>
#include <zephyr.h>

static const char *banner1 = "Send characters to the UART device\r\n";
static const char *banner2 = "Characters read:\r\n";

static volatile bool data_transmitted;
static volatile bool data_arrived;
static	char data_buf[64];

static void interrupt_handler(struct device *dev)
{
	uart_irq_update(dev);

	if (uart_irq_tx_ready(dev)) {
		data_transmitted = true;
	}

	if (uart_irq_rx_ready(dev)) {
		data_arrived = true;
	}
}

static void write_data(struct device *dev, const char *buf, int len)
{
	uart_irq_tx_enable(dev);

	while (len) {
		int written;

		data_transmitted = false;
		written = uart_fifo_fill(dev, (const u8_t *)buf, len);
		while (data_transmitted == false) {
			k_yield();
		}

		len -= written;
		buf += written;
	}

	uart_irq_tx_disable(dev);
}

static void read_and_echo_data(struct device *dev, int *bytes_read)
{
	while (data_arrived == false)
		;

	data_arrived = false;

	/* Read all data and echo it back */
	while ((*bytes_read = uart_fifo_read(dev,
	    (u8_t *)data_buf, sizeof(data_buf)))) {
		write_data(dev, data_buf, *bytes_read);
	}
}

void main(void)
{
	struct device *dev;
	u32_t baudrate, bytes_read, dtr = 0U;
	int ret;

	dev = device_get_binding("CDC_ACM_0");
	if (!dev) {
		printf("CDC ACM device not found\n");
		return;
	}

	printf("Wait for DTR\n");
	while (1) {
		uart_line_ctrl_get(dev, LINE_CTRL_DTR, &dtr);
		if (dtr)
			break;
	}
	printf("DTR set, start test\n");

	/* They are optional, we use them to test the interrupt endpoint */
	ret = uart_line_ctrl_set(dev, LINE_CTRL_DCD, 1);
	if (ret)
		printf("Failed to set DCD, ret code %d\n", ret);

	ret = uart_line_ctrl_set(dev, LINE_CTRL_DSR, 1);
	if (ret)
		printf("Failed to set DSR, ret code %d\n", ret);

	/* Wait 1 sec for the host to do all settings */
	k_busy_wait(1000000);

	ret = uart_line_ctrl_get(dev, LINE_CTRL_BAUD_RATE, &baudrate);
	if (ret)
		printf("Failed to get baudrate, ret code %d\n", ret);
	else
		printf("Baudrate detected: %d\n", baudrate);

	uart_irq_callback_set(dev, interrupt_handler);
	write_data(dev, banner1, strlen(banner1));
	write_data(dev, banner2, strlen(banner2));

	/* Enable rx interrupts */
	uart_irq_rx_enable(dev);

	/* Echo the received data */
	while (1) {
		read_and_echo_data(dev, (int *) &bytes_read);
	}
}