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/*
* Copyright (c) 2006-2025, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2025-07-22 kurisaw first version
*/
#include <rtdevice.h>
#include <hal_data.h>
#include "drv_rs485.h"
#define DBG_TAG "drv.rs485"
#define DBG_LVL DBG_LOG
#include <rtdbg.h>
#ifdef BSP_USING_RS485
#define RS485_OUT rt_pin_write((rt_base_t)RS485_DE_PIN, PIN_HIGH)
#define RS485_IN rt_pin_write((rt_base_t)RS485_DE_PIN, PIN_LOW)
static rt_device_t rs485_serial = RT_NULL;
static struct rt_semaphore rs485_rx_sem;
static struct rt_ringbuffer rs485_rx_rb;
static rt_uint8_t rs485_rx_buffer[RS485_RX_BUFFER_SIZE];
/* uart receive data callback function */
static rt_err_t rs485_input(rt_device_t dev, rt_size_t size)
{
if (size > 0)
{
rt_uint8_t ch;
while (rt_device_read(dev, 0, &ch, 1) == 1)
{
rt_ringbuffer_put_force(&rs485_rx_rb, &ch, 1);
}
rt_sem_release(&rs485_rx_sem);
}
return RT_EOK;
}
/* send data */
int rs485_send_data(const void *tbuf, rt_uint16_t t_len)
{
RT_ASSERT(tbuf != RT_NULL);
/* change rs485 mode to transmit */
RS485_OUT;
/* send data */
rt_size_t sent = rt_device_write(rs485_serial, 0, tbuf, t_len);
if (sent != t_len)
{
/* Transmission failed, switch back to receive mode */
RS485_IN;
return -RT_ERROR;
}
/* Note: We don't switch back to receive mode here -
that will be done in the tx_complete callback (rs485_output) */
LOG_I("send==>>");
for (int i = 0; i < t_len; i++)
{
LOG_I(" %d: %c ", i, ((rt_uint8_t *)tbuf)[i]);
}
RS485_IN;
return RT_EOK;
}
#ifndef BSP_USING_LED_MATRIX_RS485_DEMO
static void rs485_thread_entry(void *parameter)
{
rt_uint8_t ch;
rt_size_t length;
while (1)
{
/* Wait for data */
rt_sem_take(&rs485_rx_sem, RT_WAITING_FOREVER);
/* Process all available data in the ring buffer */
while (length = rt_ringbuffer_get(&rs485_rx_rb, &ch, 1))
{
if (length == 1)
{
LOG_I("recv data:%c", ch);
}
}
}
}
#endif
/* rs485 rts pin init */
int rs485_init(void)
{
/* Initialize ring buffer */
rt_ringbuffer_init(&rs485_rx_rb, rs485_rx_buffer, RS485_RX_BUFFER_SIZE);
/* find uart device */
rs485_serial = rt_device_find(RS485_UART_DEVICE_NAME);
if (!rs485_serial)
{
LOG_E("find %s failed!", RS485_UART_DEVICE_NAME);
return -RT_ERROR;
}
/* Open device in interrupt mode with DMA support if available */
rt_device_open(rs485_serial, RT_DEVICE_FLAG_INT_RX | RT_DEVICE_FLAG_DMA_RX);
/* set receive data callback function */
rt_device_set_rx_indicate(rs485_serial, rs485_input);
/* Initialize RTS pin */
rt_pin_mode((rt_base_t)RS485_DE_PIN, PIN_MODE_OUTPUT);
RS485_IN;
/* Initialize semaphore */
rt_sem_init(&rs485_rx_sem, "rs485_rx_sem", 0, RT_IPC_FLAG_FIFO);
rt_thread_t thread = rt_thread_create("rs485", rs485_thread_entry, RT_NULL,
1024, 25, 10);
if (thread != RT_NULL)
{
rt_thread_startup(thread);
}
else
{
return -RT_ERROR;
}
return RT_EOK;
}
INIT_DEVICE_EXPORT(rs485_init);
void rs485_cmd(int argc, char **argv)
{
if (argc == 1)
{
LOG_I("Usage:");
LOG_I("rs485_cmd -t <message> -- send message via RS485");
}
else if (argc == 3 && rt_strcmp(argv[1], "-t") == 0)
{
char *str = argv[2];
rs485_send_data(str, rt_strnlen(str, 32));
}
return;
}
MSH_CMD_EXPORT(rs485_cmd, rs485 transmission cmd);
#endif /* BSP_USING_RS485 */
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