Circuit Python MGM240P GPIO Pull-Ups

[MHVUT]

Originally posted on the Adafruit Circuit Python forum, reposting here for the Silabs team.

After some time away from CP I am now trying again with a new development. While I wait for my custom board to come back from fabrication I am starting to get code going with the MGM240P.

First issue...the internal pull-ups or pull-downs don't seem to work. I am using CP 10.0.1. My code is...

# Configure temperature sensor alert GPIO (PB1) as an input, with a pull-up
temp_alert = digitalio.DigitalInOut(board.PB1)
temp_alert.direction = digitalio.Direction.INPUT
temp_alert.pull = digitalio.Pull.UP

When I check the pin with a DVM it is not pulled up (or down if I flip it the other way), it appears to be floating.

If I set the pin as an output and set it low or high, there are no issues, works as expected. So I know I am looking at the correct pin when it's an output.

Have I missed something here? I expected to see PB1 pull up or down, depending how it's set.

Thanks for any guidance on what I may be doing incorrectly.

[dhalbert]

@Brandon-Hurst Could you help with this? Thanks.

Sorry, wrong port!

[dhalbert]

@silabs-ChatNguyen Could you help with this? Thanks.

[tannewt]

It doesn't look like the property accessor is implemented correctly:

circuitpython/ports/silabs/common-hal/digitalio/DigitalInOut.c

Lines 148 to 158 in 3d94daa

	// Set pull direction
	digitalinout_result_t common_hal_digitalio_digitalinout_set_pull(
	digitalio_digitalinout_obj_t *self, digitalio_pull_t pull) {
	return DIGITALINOUT_OK;
	}
	// Get pull direction
	digitalio_pull_t common_hal_digitalio_digitalinout_get_pull(
	digitalio_digitalinout_obj_t *self) {
	return PULL_NONE;
	}

switch_to_input() does look correct:

circuitpython/ports/silabs/common-hal/digitalio/DigitalInOut.c

Lines 62 to 73 in 3d94daa

	// Switch pin to input
	digitalinout_result_t common_hal_digitalio_digitalinout_switch_to_input(
	digitalio_digitalinout_obj_t *self, digitalio_pull_t pull) {
	if (pull == PULL_NONE) {
	GPIO_PinModeSet(self->pin->port, self->pin->number, gpioModeInput, 1);
	} else if (pull == PULL_UP) {
	GPIO_PinModeSet(self->pin->port, self->pin->number, gpioModeInputPull, 1);
	} else {
	GPIO_PinModeSet(self->pin->port, self->pin->number, gpioModeInputPull, 0);
	}
	return DIGITALINOUT_OK;
	}

[MHVUT]

Thank you Scott. That worked, so it does appear the issue is with the Silabs CP port. My code has changed to the following, and I verified with a DVM PB1 is pulled up.

Appreciate the support.

# Configure temperature sensor alert GPIO (PB1) as an input, with a pull-up
temp_alert = digitalio.DigitalInOut(board.PB1)
temp_alert.switch_to_input(pull=digitalio.Pull.UP)