feat(wakeup): Use Macro for GPIO_NUM

Changed the example to use a #define for the RTC IO Pin (GPIO) used in the example.

libraries/ESP32/examples/DeepSleep/ExternalWakeUp/ExternalWakeUp.ino

@@ -24,6 +24,7 @@
 
 #define BUTTON_PIN_BITMASK(GPIO) (1ULL << GPIO)  // 2 ^ GPIO_NUMBER in hex
 #define USE_EXT0_WAKEUP 1  // 1 = EXT0 wakeup, 0 = EXT1 wakeup
+#define WAKEUP_GPIO GPIO_NUM_33 // Only RTC GPIO are allowed - this is a ESP32 example
 RTC_DATA_ATTR int bootCount = 0;
 
 /*
@@ -67,24 +68,24 @@ void setup() {
     RTC peripherals to be turned on.
   */
 #if USE_EXT0_WAKEUP
-  esp_sleep_enable_ext0_wakeup(GPIO_NUM_33, 1);  //1 = High, 0 = Low
+  esp_sleep_enable_ext0_wakeup(WAKEUP_GPIO, 1);  //1 = High, 0 = Low
   // Configure pullup/downs via RTCIO to tie wakeup pins to inactive level during deepsleep.
   // EXT0 resides in the same power domain (RTC_PERIPH) as the RTC IO pullup/downs.
   // No need to keep that power domain explicitly, unlike EXT1.
-  rtc_gpio_pullup_dis(GPIO_NUM_33);
-  rtc_gpio_pulldown_en(GPIO_NUM_33);
+  rtc_gpio_pullup_dis(WAKEUP_GPIO);
+  rtc_gpio_pulldown_en(WAKEUP_GPIO);
 
 #else // EXT1 WAKEUP
   //If you were to use ext1, you would use it like
-  esp_sleep_enable_ext1_wakeup_io(BUTTON_PIN_BITMASK(GPIO_NUM_33), ESP_EXT1_WAKEUP_ANY_HIGH);
+  esp_sleep_enable_ext1_wakeup_io(BUTTON_PIN_BITMASK(WAKEUP_GPIO), ESP_EXT1_WAKEUP_ANY_HIGH);
   /*
     If there are no external pull-up/downs, tie wakeup pins to inactive level with internal pull-up/downs via RTC IO
          during deepsleep. However, RTC IO relies on the RTC_PERIPH power domain. Keeping this power domain on will
          increase some power comsumption. However, if we turn off the RTC_PERIPH domain or if certain chips lack the RTC_PERIPH
          domain, we will use the HOLD feature to maintain the pull-up and pull-down on the pins during sleep.
   */
-  rtc_gpio_pulldown_en(GPIO_NUM_33);  // GPIO33 is tie to GND in order to wake up in HIGH
-  rtc_gpio_pullup_dis(GPIO_NUM_33);   // Disable PULL_UP in order to allow it to wakeup on HIGH
+  rtc_gpio_pulldown_en(WAKEUP_GPIO);  // GPIO33 is tie to GND in order to wake up in HIGH
+  rtc_gpio_pullup_dis(WAKEUP_GPIO);   // Disable PULL_UP in order to allow it to wakeup on HIGH
 #endif
   //Go to sleep now
   Serial.println("Going to sleep now");