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CCS/UCD3138A: question about analog comparator

liwei qi
Expert 1120 points
Part Number: UCD3138A

Tool/software: Code Composer Studio

The register of CMP setting by the code as follow:

FaultMuxRegs.ACOMPCTRL1.bit.ACOMP_C_THRESH = 30;

FaultMuxRegs.ACOMPCTRL1.bit.ACOMP_C_SEL = 0; 
FaultMuxRegs.ACOMPCTRL1.bit.ACOMP_C_POL = 0;

But i don't set the register bit of FaultMuxRegs.DPWM0FLTABDET.bit.ACOMP_C_EN. And i find the default value of ACOMP_C_EN is 0. but i find when the compare input blew the register of ACOMP_C_THRESH, the pwm output will be disable. why? i think the pwm output need to be disable when the bit of ACOMP_C_EN is 1.

  • 0
    TI__Genius 13570 points

    Hi, Liwei,

    DPWM could be shut off by some other protection. You can try to disable comparator to verify this.

    You can check ADC protection, DPWM0FAULTDET. Maybe they shut off DPWM.

    Regards,
    Sean

  • 0 in reply to Sean Xu
    Expert 1120 points
    Hi, Sean:
    The register of DPWM0FAULTDET is also disable. So i think that DPWM is not shutdown by them. any else?
  • 0 in reply to Sean Xu
    TI__Genius 13570 points

    Do you have interrupt enabled? Maybe it is shutdown in the firmware. You can disable comparator and see what happens.

  • 0 in reply to Sean Xu
    Expert 1120 points
    which interrupt do yo mean? it have two interrupt: one is DPWM and another is CMP. You can see the code above that i have disable the CMP interrupt as the bit of FaultMuxRegs.DPWM0FLTABDET.bit.ACOMP_C_EN is 0. But PWM also is off. I don't know why it is?
  • 0 in reply to Sean Xu
    Expert 1120 points
    ???????????????
  • 0 in reply to liwei qi
    Mastermind 7090 points
    Hi Liwei,

    Can you please post your entire initialization code? You'd better to read all the bit's value in FaultMux Register through memory debugger.

    How many analog comparators are used to shutdown DPWM0?

    I think you can refer to lab training code or any of TI's demo EVM code(like PFC) on how to configure the analog comparator to shut down DPWM.
  • 0 in reply to Jack Tan80
    Expert 1120 points
    Jack:
    How can i give you the initialization code? please give me your email address.
    Yes. I refer the demo EVM code. But i don't know where i set error or other. I have disable the CMP but the DPWM still shutdown.
    Thanks!
  • 0 in reply to liwei qi
    Mastermind 7090 points
    You can click on 'Insert code, Attached files and more...' to go to rich format, and insert your code.
  • 0 in reply to Jack Tan80
    Expert 1120 points
    Jack:
    I have sent the message to you. If i use the define for disable the CMP, but the cmp still occur and shutdown off the DPWM.
  • 0 in reply to liwei qi
    Mastermind 7090 points
    Please try a solution on clearing the bit ALL_FAULT_EN in DPWMFLTCTRL register, I believe you will get the result what you want.

    inline void init_pwm_protection(void)
    {
    volatile UINT32 tmp;

    Dpwm0Regs.DPWMFLTCTRL.bit.ALL_FAULT_EN = 0; //1;
    Dpwm0Regs.DPWMFLTCTRL.bit.AB_MAX_COUNT = MAX_FAULT_COUNT; // Set count for latched faults
    Dpwm0Regs.DPWMFLTCTRL.bit.A_MAX_COUNT = MAX_FAULT_COUNT; // Set count for latched faults
    Dpwm0Regs.DPWMFLTCTRL.bit.B_MAX_COUNT = MAX_FAULT_COUNT; // Set count for latched faults

    Dpwm1Regs.DPWMFLTCTRL.bit.ALL_FAULT_EN = 0;//1;
    Dpwm1Regs.DPWMFLTCTRL.bit.AB_MAX_COUNT = MAX_FAULT_COUNT; // Set count for latched faults
    Dpwm1Regs.DPWMFLTCTRL.bit.A_MAX_COUNT = MAX_FAULT_COUNT; // Set count for latched faults
    Dpwm1Regs.DPWMFLTCTRL.bit.B_MAX_COUNT = MAX_FAULT_COUNT; // Set count for latched faults

    Dpwm2Regs.DPWMFLTCTRL.bit.ALL_FAULT_EN = 0;//1;
    Dpwm2Regs.DPWMFLTCTRL.bit.AB_MAX_COUNT = MAX_FAULT_COUNT; // Set count for latched faults
    Dpwm2Regs.DPWMFLTCTRL.bit.A_MAX_COUNT = MAX_FAULT_COUNT; // Set count for latched faults
    Dpwm2Regs.DPWMFLTCTRL.bit.B_MAX_COUNT = MAX_FAULT_COUNT; // Set count for latched faults

    Dpwm3Regs.DPWMFLTCTRL.bit.ALL_FAULT_EN = 0;//1;
    Dpwm3Regs.DPWMFLTCTRL.bit.AB_MAX_COUNT = MAX_FAULT_COUNT; // Set count for latched faults
    Dpwm3Regs.DPWMFLTCTRL.bit.A_MAX_COUNT = MAX_FAULT_COUNT; // Set count for latched faults
    Dpwm3Regs.DPWMFLTCTRL.bit.B_MAX_COUNT = MAX_FAULT_COUNT; // Set count for latched faults

    tmp = FaultMuxRegs.FAULTMUXINTSTAT.all; //Clear all interrupt flags.
    FaultMuxRegs.ACOMPCTRL0.bit.ACOMP_EN = 1; //Enable analog comparators for now
    }