[参考译文] LAUNCHXL-F280025C：将 SCI 纳入通用电机控制实验时出现问题

您好 Charlie、

您是否可以访问逻辑分析仪或示波器、以便查看 TX/RX 线路？ 我认为、这将是查看是否至少 C2000 发送任何 回显命令的第一步。

此致、

彼得

它肯定回显了我在回声实验室中发送的内容。  它似乎没有在通用电机控制实验室收到数据。  我不确定是否需要为接收数据创建另一个线程。  当我在实验的 readCharArray 代码中设置断点时、没有将数据放入控制手柄数据变量中。  有分析仪和示波器、  在实验室中运行代码时、是否应该将其放在引脚上？  我想我可能会尝试从电机实验室回显。   

这是回显实验中修改后的代码。  我只是从 Jetson orin nano 上的 python 程序发送数字 3127

//#############################################################################
//
// FILE:   sci_ex3_echoback.c
//
// TITLE:  SCI echoback example.
//
//! \addtogroup driver_example_list
//! <h1>SCI Echoback</h1>
//!
//!  This test receives and echo-backs data through the SCI-A port.
//!
//!  A terminal such as 'putty' can be used to view the data from
//!  the SCI and to send information to the SCI. Characters received
//!  by the SCI port are sent back to the host.
//!
//!  \b Running \b the \b Application
//!  Open a COM port with the following settings using a terminal:
//!  -  Find correct COM port
//!  -  Bits per second = 9600
//!  -  Data Bits = 8
//!  -  Parity = None
//!  -  Stop Bits = 1
//!  -  Hardware Control = None
//!
//!  The program will print out a greeting and then ask you to
//!  enter a character which it will echo back to the terminal.
//!
//!  \b Watch \b Variables \n
//!  - loopCounter - the number of characters sent
//!
//! \b External \b Connections \n
//!  Connect the USB cable from Control card J1:A to PC
//!
//
//#############################################################################
//
//
// $Copyright:
// Copyright (C) 2025 Texas Instruments Incorporated - http://www.ti.com/
//
// Redistribution and use in source and binary forms, with or without 
// modification, are permitted provided that the following conditions 
// are met:
// 
//   Redistributions of source code must retain the above copyright 
//   notice, this list of conditions and the following disclaimer.
// 
//   Redistributions in binary form must reproduce the above copyright
//   notice, this list of conditions and the following disclaimer in the 
//   documentation and/or other materials provided with the   
//   distribution.
// 
//   Neither the name of Texas Instruments Incorporated nor the names of
//   its contributors may be used to endorse or promote products derived
//   from this software without specific prior written permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// $
//#############################################################################

//
// Included Files
//
#include "driverlib.h"
#include "device.h"

//
// Defines
//
// Define AUTOBAUD to use the autobaud lock feature
//#define AUTOBAUD

//
// Globals
//
uint16_t loopCounter = 0;

#define MSB_MASK 0xFF00
#define LSB_MASK 0x00FF
//
// Main
//
void main(void)
{
    uint16_t joystickValue = 0;
    uint16_t receivedChar;
    unsigned char *msg;
    uint16_t rxStatus = 0U;

    //
    // Configure PLL, disable WD, enable peripheral clocks.
    //
    Device_init();

    //
    // Disable pin locks and enable internal pullups.
    //
    Device_initGPIO();

    //
    // SCI Rx pin configuration.
    //
    GPIO_setPinConfig(DEVICE_GPIO_CFG_SCIRXDA);
    GPIO_setDirectionMode(DEVICE_GPIO_PIN_SCIRXDA, GPIO_DIR_MODE_IN);
    GPIO_setPadConfig(DEVICE_GPIO_PIN_SCIRXDA, GPIO_PIN_TYPE_STD);
    GPIO_setQualificationMode(DEVICE_GPIO_PIN_SCIRXDA, GPIO_QUAL_ASYNC);

    //
    // SCI Tx pin configuration.
    //
    GPIO_setPinConfig(DEVICE_GPIO_CFG_SCITXDA);
    GPIO_setDirectionMode(DEVICE_GPIO_PIN_SCITXDA, GPIO_DIR_MODE_OUT);
    GPIO_setPadConfig(DEVICE_GPIO_PIN_SCITXDA, GPIO_PIN_TYPE_STD);
    GPIO_setQualificationMode(DEVICE_GPIO_PIN_SCITXDA, GPIO_QUAL_ASYNC);

    //
    // Initialize interrupt controller and vector table.
    //
    Interrupt_initModule();
    Interrupt_initVectorTable();

    //
    // Initialize SCIA and its FIFO.
    //
    SCI_performSoftwareReset(SCIA_BASE);

    //
    // Configure SCIA for echoback.
    //
    SCI_setConfig(SCIA_BASE, DEVICE_LSPCLK_FREQ, 115200, (SCI_CONFIG_WLEN_8 |
                                                        SCI_CONFIG_STOP_ONE |
                                                        SCI_CONFIG_PAR_NONE));
    SCI_resetChannels(SCIA_BASE);
    SCI_resetRxFIFO(SCIA_BASE);
    SCI_resetTxFIFO(SCIA_BASE);
    SCI_clearInterruptStatus(SCIA_BASE, SCI_INT_TXFF | SCI_INT_RXFF);
    SCI_enableFIFO(SCIA_BASE);
    SCI_enableModule(SCIA_BASE);
    SCI_performSoftwareReset(SCIA_BASE);

#ifdef AUTOBAUD
    //
    // Perform an autobaud lock.
    // SCI expects an 'a' or 'A' to lock the baud rate.
    //
    SCI_lockAutobaud(SCIA_BASE);
#endif

    for(;;)
    {
        while(SCI_getRxFIFOStatus(SCIA_BASE) == SCI_FIFO_RX0) {}
        // Read a character from the FIFO.
        
        // receivedChar = SCI_readCharBlockingFIFO(SCIA_BASE);
        uint16_t myArray;
        SCI_readCharArray(SCIA_BASE, &myArray, 2);
        uint16_t *temp_num = &myArray;
        uint16_t temp =  (temp_num[0] << 8);
        joystickValue = temp | (temp_num[1]);
   

        rxStatus = SCI_getRxStatus(SCIA_BASE);
        if((rxStatus & SCI_RXSTATUS_ERROR) != 0)
        {
            //
            //If Execution stops here there is some error
            //Analyze SCI_getRxStatus() API return value
            //
            ESTOP0;
        }

        uint16_t value[2];
        value[0] = (joystickValue & MSB_MASK) >> 8;
        value[1] = joystickValue & LSB_MASK;
        SCI_writeCharArray(SCIA_BASE, value, 2);
        
        joystickValue = 0;
        myArray = NULL;

        // Increment the loop count variable.
        //
        loopCounter++;
    }
}

//
// End of File
//

这里是 Jetson 发送和响应从 LaunchXL-F25C 接收到的内容的视频
e2e.ti.com/.../Echo_5F00_back_5F00_video.mp4

然后我用同样的代码,并将它注入电机控制实验室后,用户启动电机与设置旗舰

以及 Jetson 发送以及从 Launchpad 接收信号的视频

e2e.ti.com/.../motor_5F00_lab_5F00_video.mp4

您可以看到它发回 0。  因此、似乎没有设置 JoystickValue、或者没有任何值通过 Rx 行。  尽管这没有意义、因为回显上运行的代码与成功返回该值的代码相同。  我觉得我在第一个问题中列出的代码中设置了所有 GPIO 和坐标线。  我可能没有、这就是为什么它不会出现的原因。 还是线程/竞态条件？  我是否需要启动新线程并从中读取 UART 数据？   

您好 Charlie、

我认为这不是线程问题、因为您将 RX 读数包含在主控制循环中。 但通常对于通信集成、优先选择在后台循环中执行通信、并利用 FIFO 来减少与目标通信所需的 CPU 带宽。 如果您可以将逻辑分析仪连接到 TX/RX 线路、最好是 UART 解码、则可以仔细检查这是硬件配置问题还是软件解码问题

此致、

彼得

您好 Charlie、  

由于 SCI 的中断优先级较低、因此不会对控制环路产生负面影响、因此您也肯定可以使用中断。 您实际上还可以参考 MCSDK 中 010265 示例代码中的实现、这展示了如何将 SCI 通信集成到电机控制结构中。 此时、我们没有任何依赖于 RTOS 的电机控制解决方案、但根据您的偏好、可能会采用类似的方法

此致、

彼得