Using UART3 same times with UART1 please

I have successfully changed the B C limit pins on RX3 and TX3. I set same configuration & IRQ for USART3. But not working. I know this not easy process. What can i do, please help me.
new 2.txt
 USART3_Configuration(u32 BaudRate) {

    GPIO_InitTypeDef GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;
    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_4);
    NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
    RCC_APB2PeriphClockCmd(
            RCC_APB1Periph_USART3 | RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO,
            ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOB, &GPIO_InitStructure);
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOB, &GPIO_InitStructure);

    USART_InitStructure.USART_BaudRate = BaudRate;
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;
    USART_InitStructure.USART_StopBits = USART_StopBits_1;
    USART_InitStructure.USART_Parity = USART_Parity_No;
    USART_InitStructure.USART_HardwareFlowControl =
            USART_HardwareFlowControl_None;
    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
    USART3->CR1 |= (USART_CR1_RE | USART_CR1_TE);
    USART_Init(USART3, &USART_InitStructure);
    //  USART_ITConfig(USART3, USART_IT_TXE, ENABLE);
    USART_ITConfig(USART3, USART_IT_RXNE, ENABLE);
    USART_Cmd(USART3, ENABLE);
}

void USART3_IRQHandler (void) 
{
    volatile unsigned int IIR;
    uint8_t data;
    uint8_t next_head;

    IIR = USART3->SR;
    if (IIR & USART_FLAG_RXNE) 
    {                  // read interrupt
        data = USART3->DR & 0x1FF;

  // Pick off realtime command characters directly from the serial stream. These characters are
  // not passed into the main buffer, but these set system state flag bits for realtime execution.
  switch (data) {
    case CMD_RESET:         mc_reset(); break; // Call motion control reset routine.
    case CMD_STATUS_REPORT: system_set_exec_state_flag(EXEC_STATUS_REPORT); break; // Set as true
    case CMD_CYCLE_START:   system_set_exec_state_flag(EXEC_CYCLE_START); break; // Set as true
    case CMD_FEED_HOLD:     system_set_exec_state_flag(EXEC_FEED_HOLD); break; // Set as true
    default :
      if (data > 0x7F) { // Real-time control characters are extended ACSII only.
        switch(data) {
          case CMD_SAFETY_DOOR:   system_set_exec_state_flag(EXEC_SAFETY_DOOR); break; // Set as true
          case CMD_JOG_CANCEL:
            if (sys.state & STATE_JOG) { // Block all other states from invoking motion cancel.
              system_set_exec_state_flag(EXEC_MOTION_CANCEL);
            }
            break;

          case CMD_FEED_OVR_RESET: system_set_exec_motion_override_flag(EXEC_FEED_OVR_RESET); break;
          case CMD_FEED_OVR_COARSE_PLUS: system_set_exec_motion_override_flag(EXEC_FEED_OVR_COARSE_PLUS); break;
          case CMD_FEED_OVR_COARSE_MINUS: system_set_exec_motion_override_flag(EXEC_FEED_OVR_COARSE_MINUS); break;
          case CMD_FEED_OVR_FINE_PLUS: system_set_exec_motion_override_flag(EXEC_FEED_OVR_FINE_PLUS); break;
          case CMD_FEED_OVR_FINE_MINUS: system_set_exec_motion_override_flag(EXEC_FEED_OVR_FINE_MINUS); break;
          case CMD_RAPID_OVR_RESET: system_set_exec_motion_override_flag(EXEC_RAPID_OVR_RESET); break;
          case CMD_RAPID_OVR_MEDIUM: system_set_exec_motion_override_flag(EXEC_RAPID_OVR_MEDIUM); break;
          case CMD_RAPID_OVR_LOW: system_set_exec_motion_override_flag(EXEC_RAPID_OVR_LOW); break;
          case CMD_SPINDLE_OVR_RESET: system_set_exec_accessory_override_flag(EXEC_SPINDLE_OVR_RESET); break;
          case CMD_SPINDLE_OVR_COARSE_PLUS: system_set_exec_accessory_override_flag(EXEC_SPINDLE_OVR_COARSE_PLUS); break;
          case CMD_SPINDLE_OVR_COARSE_MINUS: system_set_exec_accessory_override_flag(EXEC_SPINDLE_OVR_COARSE_MINUS); break;
          case CMD_SPINDLE_OVR_FINE_PLUS: system_set_exec_accessory_override_flag(EXEC_SPINDLE_OVR_FINE_PLUS); break;
          case CMD_SPINDLE_OVR_FINE_MINUS: system_set_exec_accessory_override_flag(EXEC_SPINDLE_OVR_FINE_MINUS); break;
          case CMD_SPINDLE_OVR_STOP: system_set_exec_accessory_override_flag(EXEC_SPINDLE_OVR_STOP); break;
          case CMD_COOLANT_FLOOD_OVR_TOGGLE: system_set_exec_accessory_override_flag(EXEC_COOLANT_FLOOD_OVR_TOGGLE); break;

            case CMD_COOLANT_MIST_OVR_TOGGLE: system_set_exec_accessory_override_flag(EXEC_COOLANT_MIST_OVR_TOGGLE); break;

        }
        // Throw away any unfound extended-ASCII character by not passing it to the serial buffer.
      } else { // Write character to buffer
        next_head = serial_rx_buffer_head + 1;
        if (next_head == RX_RING_BUFFER) { next_head = 0; }

        // Write data to buffer unless it is full.
        if (next_head != serial_rx_buffer_tail) {
          serial_rx_buffer[serial_rx_buffer_head] = data;
          serial_rx_buffer_head = next_head;
        }
      }
  }

        USART3->SR &= ~USART_FLAG_RXNE;           // clear interrupt

   }

}
robomechs / 6-AXIS-USBCNC-GRBL

Using UART3 same times with UART1 please #42
