modbus_it.c

// где-то в теле 
RS485_ENABLE_RX();

huart2.ErrorCode = HAL_UART_ERROR_NONE;
huart2.RxState = HAL_UART_STATE_BUSY_RX;

__HAL_UART_ENABLE_IT(&huart2, UART_IT_RXNE);
/******************************/



void modbusMasterGotByte() {
    request.state = MODBUS_STATE_RX;

    request.buffer[bufferPos] = (uint8_t)(modbusUart.Instance->DR & (uint8_t)0x00FF);
    bufferPos++;

    HAL_TIM_Base_Stop_IT(&modbusIntervalTimer);
    TIM1->CNT = 0;
    HAL_TIM_Base_Start_IT(&modbusIntervalTimer);
}

void modbusMasterEndOfFrame(void) {
    HAL_TIM_Base_Stop_IT(&modbusIntervalTimer);
    __HAL_UART_DISABLE_IT(&modbusUart, UART_IT_RXNE);
    modbusUart.RxState = HAL_UART_STATE_READY;

    request.state = MODBUS_STATE_GOT_FRAME;
}