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CCS/TMS320F28335: CCS/TMS320F28335:

user6083218
Prodigy 240 points

Part Number: TMS320F28335

Tool/software: Code Composer Studio

I use gpio25 as ecap2 APWM function output pins, when

SysCtrlRegs. PCLKCR1. Bit. ECAP2ENCLK = 0,

gpio25 pin is 1 v,

in fact, I need to make gpio25 0 v, how to set?

  • 0
    TI__Guru 50611 points

    Hi,

    I am checking with eCAP expert and will get back to you by Monday.

  • 0 in reply to Santosh Jha
    TI__Guru 50611 points

    Hi,

    Do you still having the issue or you have resolved the issue?

    You can write 0 to GPIO25DAT register that will drive the pin to 0 when eCAP is not driving it.

  • 0 in reply to Santosh Jha
    Prodigy 240 points

    According to your suggestion, the change is valid, but there is a new problem, the program will report an error after a few seconds, please check my picture

  • 0 in reply to user6083218
    Prodigy 240 points

    Each time this problem occurs, the output level of the crystal oscillator rises, and so does the supply voltage of the crystal oscillator.
    In the picture, the blue curve is crystal output and the red curve is 3.3V power supply

  • 0 in reply to user6083218
    TI__Guru* 83080 points

    GPIO25 has an internal pullup that is enabled by default on power up/reset.  You can use the PUDIS bit to de-activate this after program execution, but this may be a problem since you are using this as a PWM and it will try and turn on the FET until you can get control of the pin, and let the eCAP control it.  

    The PU is relatively weak, at 2uA, so in this case I would recommend putting an external pulldown resistor to overdrive the 2uA. The main ePWM pins(GPIO0-12) have their internal PU disabled by default for this reason.

    I think the rise in the X-tal signal is just tied to the rise you see on VDDIO.  I'm not really sure the reason for this; can you comment on the example or kit source file you are showing in your screenshot?  We may need to direct you to the appropriate system application engineer for further debug.

    Best,

    Matthew