9322a238db
The STM32 single_wire example was merged in parallel to this sample and ended up as a sub-folder of this one. Separate both into their own folders. Signed-off-by: Martin Jäger <martin@libre.solar>
94 lines
2.1 KiB
C
94 lines
2.1 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.h>
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#include <device.h>
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#include <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 *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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uart_irq_callback_user_data_set(uart_dev, serial_cb, NULL);
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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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