STM32 操作系统串口中断发送异常问题

uint8_t analogOutChlSet(uint8_t dev,analog_out_ch_e channel,uint16_t val)
{
    uint8_t ret=0;
    uint8_t send_buf[32]={0};
    uint16_t send_len=0;
    
    mb_req_s req={0};
    MSGQUEUE_OBJ_t msg;
    
    req.Id=dev;
    req.Func=0x06;
    req.RW_Reg=channel;
    req.RW_Value[0]=val;
    
    // 生成命令
    ret=mbMasGen(send_buf,&send_len,&req);
    if(ret){
        LOG_ERROR(0,"mbMasGen Param Error:%d",ret);
        return 1;
    }
    
    // 发送命令
    rs485Send(LINK_RS485_UP,send_buf,send_len);
    
    // 等待响应
    if(osMessageQueueGet(gParam.os_msg_com_ext,&msg,NULL,1000)!=osOK){
        LOG_ERROR(0,"mbMasGen no reply");
        return 2;
    }
    
    // 重新打开接收
    uartComExtRecv();
    
    // 判定响应是否正确
    ret=mbMasAth(msg.msg_buf,msg.msg_length,&req);
    if(ret){
        LOG_ERROR(0,"mbMasAth response error:%d",ret);
        return 3;
    }
    
    return 0;
}