433_STM32/Core/Src/modbus_rtu_master.c

#include "modbus_rtu_master.h"
#include "usart.h"
#include "main.h"
#include <string.h>

static const uint16_t crc16_table[256] = {
    0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
    0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
    0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40,
    0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841,
    0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40,
    0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41,
    0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641,
    0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040,
    0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240,
    0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441,
    0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41,
    0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840,
    0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41,
    0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40,
    0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640,
    0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041,
    0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240,
    0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441,
    0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41,
    0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840,
    0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41,
    0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40,
    0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640,
    0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041,
    0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241,
    0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440,
    0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40,
    0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841,
    0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40,
    0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41,
    0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641,
    0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040
};

typedef enum {
    MB_STATE_IDLE,
    MB_STATE_WAIT_POLL,
    MB_STATE_WAIT_RESPONSE,
    MB_STATE_PROCESS
} mb_state_t;

static mb_state_t mb_state = MB_STATE_IDLE;
static uint32_t mb_state_tick = 0;
static uint32_t mb_last_poll_tick = 0;
static uint32_t ignore_echo_until = 0;

static uint8_t mb_rx_buf[MODBUS_RTU_MAX_RX_BUF];
static uint8_t mb_rx_idx = 0;
static uint32_t mb_rx_last_byte_tick = 0;

static uint8_t mb_alarm_state = 0;
static uint8_t mb_alarm_last = 0xFF;
static uint16_t mb_reg_val = 0;

static uint16_t modbus_crc16(const uint8_t *data, uint16_t len)
{
    uint16_t crc = 0xFFFF;
    for (uint16_t i = 0; i < len; i++) {
        crc = (crc >> 8) ^ crc16_table[(crc ^ data[i]) & 0xFF];
    }
    return crc;
}

static uint8_t extract_alarm_bits(uint16_t reg)
{
    uint8_t alarm = 0;
    if (NORIS_FIRE_ALARM(reg))  alarm |= (1 << 0);
    if (NORIS_DOOR_ALARM(reg))  alarm |= (1 << 1);
    if (NORIS_BILGE_ALARM(reg)) alarm |= (1 << 2);
    if (NORIS_GAS_ALARM(reg))   alarm |= (1 << 3);
    return alarm;
}

static void send_modbus_request(void)
{
    uint8_t tx[8];
    tx[0] = MODBUS_RTU_SLAVE_ADDR;
    tx[1] = 0x03;
    tx[2] = (uint8_t)(MODBUS_RTU_TARGET_REG >> 8);
    tx[3] = (uint8_t)(MODBUS_RTU_TARGET_REG & 0xFF);
    tx[4] = (uint8_t)(MODBUS_RTU_REG_QTY >> 8);
    tx[5] = (uint8_t)(MODBUS_RTU_REG_QTY & 0xFF);
    uint16_t crc = modbus_crc16(tx, 6);
    tx[6] = (uint8_t)(crc & 0xFF);
    tx[7] = (uint8_t)(crc >> 8);

    ignore_echo_until = HAL_GetTick() + MODBUS_RTU_TX_ECHO_MARGIN;
    mb_rx_idx = 0;

    HAL_UART_Transmit(&huart3, tx, 8, HAL_MAX_DELAY);
}

static bool parse_modbus_response(void)
{
    if (mb_rx_idx < 5) return false;

    if (mb_rx_buf[0] != MODBUS_RTU_SLAVE_ADDR) return false;
    if (mb_rx_buf[1] != 0x03) return false;

    uint8_t byte_count = mb_rx_buf[2];
    if (byte_count != (MODBUS_RTU_REG_QTY * 2)) return false;

    uint16_t expected_len = 3 + byte_count + 2;
    if (mb_rx_idx < expected_len) return false;

    uint16_t crc_received = (uint16_t)mb_rx_buf[expected_len - 2]
                          | ((uint16_t)mb_rx_buf[expected_len - 1] << 8);
    uint16_t crc_calc = modbus_crc16(mb_rx_buf, expected_len - 2);
    if (crc_received != crc_calc) return false;

    mb_reg_val = ((uint16_t)mb_rx_buf[3] << 8) | mb_rx_buf[4];
    return true;
}

void ModbusRTU_Master_Init(void)
{
    mb_state = MB_STATE_IDLE;
    mb_state_tick = HAL_GetTick();
    mb_last_poll_tick = HAL_GetTick();
    mb_rx_idx = 0;
    mb_alarm_state = 0;
    mb_alarm_last = 0xFF;
    mb_reg_val = 0;
    ignore_echo_until = 0;
}

void ModbusRTU_Master_Task(void)
{
    switch (mb_state) {
    case MB_STATE_IDLE:
        if ((int32_t)(HAL_GetTick() - mb_last_poll_tick) >= MODBUS_RTU_POLL_INTERVAL) {
            mb_last_poll_tick = HAL_GetTick();
            mb_state = MB_STATE_WAIT_POLL;
            mb_state_tick = HAL_GetTick();
        }
        break;

    case MB_STATE_WAIT_POLL:
        send_modbus_request();
        mb_state = MB_STATE_WAIT_RESPONSE;
        mb_state_tick = HAL_GetTick();
        break;

    case MB_STATE_WAIT_RESPONSE:
        if (mb_rx_idx > 0 && (int32_t)(HAL_GetTick() - mb_rx_last_byte_tick) > MODBUS_RTU_INTER_CHAR_TIMEOUT) {
            mb_state = MB_STATE_PROCESS;
            break;
        }
        if ((int32_t)(HAL_GetTick() - mb_state_tick) > MODBUS_RTU_RESP_TIMEOUT) {
            mb_state = MB_STATE_IDLE;
        }
        break;

    case MB_STATE_PROCESS:
        if (parse_modbus_response()) {
            mb_alarm_state = extract_alarm_bits(mb_reg_val);
            if (mb_alarm_state != mb_alarm_last) {
                if (mb_alarm_last != 0xFF) {
                    extern void RF433_SendPacket(uint8_t type, const uint8_t *payload, uint8_t len);
                    RF433_SendPacket(PROTO_TYPE_MODBUS_RTU, &mb_alarm_state, 1);
                }
                mb_alarm_last = mb_alarm_state;
            }
        }
        mb_state = MB_STATE_IDLE;
        break;

    default:
        mb_state = MB_STATE_IDLE;
        break;
    }
}

void ModbusRTU_FeedRxByte(uint8_t byte)
{
    if (HAL_GetTick() < ignore_echo_until) return;

    if (mb_state != MB_STATE_WAIT_RESPONSE) return;

    if (mb_rx_idx >= MODBUS_RTU_MAX_RX_BUF) return;

    mb_rx_buf[mb_rx_idx++] = byte;
    mb_rx_last_byte_tick = HAL_GetTick();
}

uint8_t ModbusRTU_GetAlarmState(void)
{
    return mb_alarm_state;
}