rs485 forcing set rst and dtr

rs485.cpp

#include <stdlib.h>
#include <time.h>
#include <string.h>
#include <assert.h>

#include "esp_mac.h"
#include "esp_log.h"
#include "config.h"

#include "rs485.h"

#define RS485_BAUDRATE              (115200)

#define RS485_UART_PORT             (UART_NUM_2)

#define RS485_UART_TXD              (GPIO_NUM_16)   // DI
#define RS485_UART_RXD              (GPIO_NUM_17)   // RO
#define RS485_UART_RTS              (GPIO_NUM_13)   // RE
#define RS485_UART_CTS              (UART_PIN_NO_CHANGE)


#define RS485_BUF_SIZE              125

static const char *TAG = "rs485";

esp_err_t Rs485::setup()
{
    uart_config_t uart_config = {
        .baud_rate = RS485_BAUDRATE,
        .data_bits = UART_DATA_8_BITS,
        .parity = UART_PARITY_DISABLE,
        .stop_bits = UART_STOP_BITS_1,
        .flow_ctrl = UART_HW_FLOWCTRL_DISABLE,
        .rx_flow_ctrl_thresh = 122,
        .source_clk = UART_SCLK_APB,
    };

    ESP_ERROR_CHECK(uart_driver_install(RS485_UART_PORT, RS485_BUF_SIZE * 2, 0, 0, NULL, 0));
    ESP_ERROR_CHECK(uart_param_config(RS485_UART_PORT, &uart_config));
    ESP_ERROR_CHECK(uart_set_pin(RS485_UART_PORT, RS485_UART_TXD, RS485_UART_RXD, RS485_UART_RTS, RS485_UART_CTS));
    ESP_ERROR_CHECK(uart_set_mode(RS485_UART_PORT, UART_MODE_RS485_HALF_DUPLEX));

    return ESP_OK;
}

esp_err_t Rs485::reset()
{
    esp_err_t err = uart_driver_delete(RS485_UART_PORT);
    if (err != ESP_OK) {
        return err;
    }
    return this->setup();
}

bool Rs485::send(const uint8_t * buffer, size_t size)
{
    bool response = false;

    uart_set_rts(RS485_UART_PORT, 1);
    size_t ret = uart_write_bytes(RS485_UART_PORT, buffer, size);
    if (ret == size) {
        uart_wait_tx_done(RS485_UART_PORT, (50 / portTICK_PERIOD_MS));
    }
    uart_set_rts(RS485_UART_PORT, 0);
    return ret != size ? false : true;
}

int16_t Rs485::read(uint8_t *buffer, size_t size)
{
    uart_set_dtr(RS485_UART_PORT, 1);
    register int16_t n = uart_read_bytes(RS485_UART_PORT, buffer, size, (10 / portTICK_PERIOD_MS));
    if (n != 0 && n != -1) {
        uart_flush_input(RS485_UART_PORT);
    }
    uart_set_dtr(RS485_UART_PORT, 0);
    return n == -1 ? 0 : n;
}