KV10 PTC6 & PTC7

[stephenmonn]

I'm having a problem running PTC6 and PTC7 as GPIO. The microcontroller is an MKV10Z16VLC7.

First I initialize the pin for GPIO

PORT_HAL_SetMuxMode(PORTC, 7UL, kPortMuxAsGpio);

gpio_output_pin_user_config_t CLK = {

  .pinName = GPIO_MAKE_PIN(GPIOC_IDX, 7U),

  .config.outputLogic = 0,

  .config.slewRate = kPortFastSlewRate,

  .config.driveStrength = kPortLowDriveStrength,

};

GPIO_DRV_OutputPinInit(&CLK);

Then I try toggling the pin manually

  GPIO_WR_PSOR(GPIOC, 1U << 7U);

  GPIO_WR_PCOR(GPIOC, 1U << 7U);

But this does not work. The pin stays low. And if I try to pull the whole port high, all the pins go high except PTC6 and PTC7.

  GPIO_WR_PDOR(GPIOC, 0xFF);

From the datasheet I can see that these two pins are CMP0_INx by default. Is there some sort of internal pull down that I need disable? The pins aren't connected to anything on the PCB either.

[jozefcicka-b508 · Accepted solution]

Hi Stephen, PTC6 and PTC7 are true open drain pins. These pins cannot drive a logic one without a pull-up resistor. If you want use these pins as GPIO then you must have external pull-up resistor.