8c8d41c32f
Print an error message if the UART doesn't support FIFO mode or FIFO mode is not enabled. Previously the sample would run with no errors, but wouldn't receive or echo any data. Signed-off-by: Trent Piepho <tpiepho@gmail.com>
105 lines
2.4 KiB
C
105 lines
2.4 KiB
C
/*
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* Copyright (c) 2022 Libre Solar Technologies GmbH
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <zephyr/kernel.h>
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#include <zephyr/device.h>
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#include <zephyr/drivers/uart.h>
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#include <string.h>
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/* change this to any other UART peripheral if desired */
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#define UART_DEVICE_NODE DT_CHOSEN(zephyr_shell_uart)
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#define MSG_SIZE 32
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/* queue to store up to 10 messages (aligned to 4-byte boundary) */
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K_MSGQ_DEFINE(uart_msgq, MSG_SIZE, 10, 4);
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static const struct device *const uart_dev = DEVICE_DT_GET(UART_DEVICE_NODE);
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/* receive buffer used in UART ISR callback */
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static char rx_buf[MSG_SIZE];
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static int rx_buf_pos;
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/*
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* Read characters from UART until line end is detected. Afterwards push the
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* data to the message queue.
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*/
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void serial_cb(const struct device *dev, void *user_data)
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{
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uint8_t c;
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if (!uart_irq_update(uart_dev)) {
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return;
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}
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while (uart_irq_rx_ready(uart_dev)) {
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uart_fifo_read(uart_dev, &c, 1);
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if ((c == '\n' || c == '\r') && rx_buf_pos > 0) {
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/* terminate string */
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rx_buf[rx_buf_pos] = '\0';
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/* if queue is full, message is silently dropped */
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k_msgq_put(&uart_msgq, &rx_buf, K_NO_WAIT);
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/* reset the buffer (it was copied to the msgq) */
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rx_buf_pos = 0;
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} else if (rx_buf_pos < (sizeof(rx_buf) - 1)) {
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rx_buf[rx_buf_pos++] = c;
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}
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/* else: characters beyond buffer size are dropped */
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}
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}
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/*
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* Print a null-terminated string character by character to the UART interface
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*/
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void print_uart(char *buf)
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{
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int msg_len = strlen(buf);
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for (int i = 0; i < msg_len; i++) {
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uart_poll_out(uart_dev, buf[i]);
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}
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}
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void main(void)
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{
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char tx_buf[MSG_SIZE];
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if (!device_is_ready(uart_dev)) {
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printk("UART device not found!");
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return;
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}
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/* configure interrupt and callback to receive data */
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int ret = uart_irq_callback_user_data_set(uart_dev, serial_cb, NULL);
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if (ret < 0) {
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if (ret == -ENOTSUP) {
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printk("Interrupt-driven UART API support not enabled\n");
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} else if (ret == -ENOSYS) {
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printk("UART device does not support interrupt-driven API\n");
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} else {
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printk("Error setting UART callback: %d\n", ret);
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}
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return;
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}
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uart_irq_rx_enable(uart_dev);
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print_uart("Hello! I'm your echo bot.\r\n");
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print_uart("Tell me something and press enter:\r\n");
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/* indefinitely wait for input from the user */
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while (k_msgq_get(&uart_msgq, &tx_buf, K_FOREVER) == 0) {
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print_uart("Echo: ");
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print_uart(tx_buf);
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print_uart("\r\n");
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}
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}
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