Espressif: disable pull-up on AnalogIn creation

dhalbert · dhalbert · commit 99dc4029dcad · 2022-04-06T11:33:56.000-04:00
diff --git a/ports/espressif/common-hal/analogio/AnalogIn.c b/ports/espressif/common-hal/analogio/AnalogIn.c
@@ -55,6 +55,10 @@ void common_hal_analogio_analogin_construct(analogio_analogin_obj_t *self,
     }
     common_hal_mcu_pin_claim(pin);
     self->pin = pin;
+    // Pull-ups are enabled by default for power-saving reasons on quiescent pins.
+    // Turn off the pull-up as soon as we know the pin will be used for analog reads,
+    // since it may take a while for the voltage to stabilize if the input is high-impedance.
+    gpio_pullup_dis(pin->number);
 }
 
 bool common_hal_analogio_analogin_deinited(analogio_analogin_obj_t *self) {

Original file line number	Diff line number	Diff line change
`@@ -55,6 +55,10 @@ void common_hal_analogio_analogin_construct(analogio_analogin_obj_t *self,`
`55`	`55`	`}`
`56`	`56`	`common_hal_mcu_pin_claim(pin);`
`57`	`57`	`self->pin = pin;`
	`58`	`+ // Pull-ups are enabled by default for power-saving reasons on quiescent pins.`
	`59`	`+ // Turn off the pull-up as soon as we know the pin will be used for analog reads,`
	`60`	`+ // since it may take a while for the voltage to stabilize if the input is high-impedance.`
	`61`	`+ gpio_pullup_dis(pin->number);`
`58`	`62`	`}`
`59`	`63`
`60`	`64`	`bool common_hal_analogio_analogin_deinited(analogio_analogin_obj_t *self) {`