Merge pull request #6246 from DavePutz/issue_6148

Don't reset GPIO4 on the MagTag (used for voltage monitoring)
adafruit · Apr 6, 2022 · dbb6f5f · dbb6f5f
2 parents 742c05d + 99dc402
commit dbb6f5f
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diff --git a/ports/espressif/boards/adafruit_magtag_2.9_grayscale/board.c b/ports/espressif/boards/adafruit_magtag_2.9_grayscale/board.c
@@ -188,6 +188,10 @@ bool espressif_board_reset_pin_number(gpio_num_t pin_number) {
         gpio_config(&cfg);
         return true;
     }
+    // Pin 4 is used for voltage monitoring, so don't reset
+    if (pin_number == 4) {
+        return true;
+    }
     return false;
 }
 

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) {