[参考译文] TMS320F28P559SJ-Q1：eCAP1 未在 GPIO24（引导引脚）上捕获 PWM–TMS320F28P55

https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/1599102/tms320f28p559sj-q1-ecap1-not-capturing-pwm-on-gpio24-boot-pin-tms320f28p55

器件型号： TMS320F28P559SJ-Q1

您好、

我正在使用 TMS320F28P55（64 引脚） 定制 ESC 板。 我想捕获  打开的 PWM 输入 (~50Hz、3.3V) GPIO24 、也是 BOOT 引脚 、使用 eCAP1 。 MCU 启动正常、我验证了 PWM 信号是否到达引脚。

我无法捕获 CAP1 CAP2 Cap3、但 TSCTR 会根据时钟配置增加。

    //Gpio init for Ecap input
    GpioCtrlRegs.GPAMUX2.bit.GPIO24 =  0;
    GpioCtrlRegs.GPADIR.bit.GPIO24  =  0;
    GpioCtrlRegs.GPAPUD.bit.GPIO24  =  0;

   void EscController::initEcap(){
    EALLOW;
    ECap2Regs.ECCTL0.bit.INPUTSEL = 0; // Use default ECAP1 input pin
    InputXbarRegs.INPUT1SELECT = 24;  // INPUT1 now gets data from GPIO6
    ECap2Regs.ECEINT.bit.CEVT4 = 1;      // Enable interrupt on 4th capture2
    ECap2Regs.ECCTL1.bit.CAP1POL = 0;    // Rising edge
    ECap2Regs.ECCTL1.bit.CAP2POL = 1;    // Falling edge
    ECap2Regs.ECCTL1.bit.CAP3POL = 0;    // Rising edge again (for full period)
    ECap2Regs.ECCTL1.bit.CAP4POL = 1;    // Falling edge2
    ECap2Regs.ECCTL1.bit.CTRRST1 = 1;    // Reset counter after CAP1
    ECap2Regs.ECCTL1.bit.CTRRST2 = 1;    // Reset after CAP2
    ECap2Regs.ECCTL1.bit.CTRRST3 = 0;    
    ECap2Regs.ECCTL1.bit.CTRRST4 = 1;    // Reset after CAP42
    ECap2Regs.ECCTL1.bit.CAPLDEN = 1;    // Load the time stamp to register
    ECap2Regs.ECCTL2.bit.CONT_ONESHT = 0;  // Continuous mode
    ECap2Regs.ECCTL2.bit.STOP_WRAP = 3;    // Stop at 4rd event
    ECap2Regs.ECCTL2.bit.CAP_APWM = 0;     // Capture mode
    ECap2Regs.ECCTL2.bit.SYNCI_EN = 0;     // Disable sync in
    ECap2Regs.ECCTL2.bit.SYNCO_SEL = 0;    // Pass through
    ECap2Regs.ECCTL2.bit.TSCTRSTOP = 1;    // Start counter
    ECap2Regs.ECCTL2.bit.REARM = 1;        // Arm the eCAP
    EDIS;
}