M5 touch wakeup read coordinates

cthulu

Hi, I am trying to update my weatherapp (modified from an open source project) to wake up when the screen is touched. I want to read the coordinates after the wakeup, do something, and go back to deep sleep (for 1hr).

My proto-code is something like this

#include <M5EPD.h>

M5EPD_Canvas canvas(&M5.EPD);

int x, y= 0;
void setup()
{
   M5.begin();
   M5.EPD.SetRotation(0);
   M5.EPD.Clear(true);
   canvas.createCanvas(960, 540);
   canvas.setTextSize(5);
   canvas.drawString("Touch The Screen!", 400, 20);
   canvas.pushCanvas(0, 0, UPDATE_MODE_DU4);
}

void loop()
{

   if (M5.TP.available() || esp_sleep_get_wakeup_cause() == ESP_SLEEP_WAKEUP_TOUCHPAD)
   {
      M5.TP.update();
      tp_finger_t fingerItem = M5.TP.readFinger(0);
      x = fingerItem.x;
      y = fingerItem.y;
      canvas.setTextSize(5);
      canvas.drawFloat(x, 0, 400, 60);
      canvas.drawFloat(y, 0, 400, 60);
      canvas.pushCanvas(0, 0, UPDATE_MODE_DU4);
   }
  
   // Clear out all previous touch screen interrupts
   while(digitalRead(GPIO_NUM_36) == LOW)
   {
      M5.TP.flush();
      delay(10);
   }

   Serial.println("before sleep");
   Serial.flush();
   delay(1000);

   // Enable timer (3600 s)
   esp_sleep_enable_timer_wakeup(3600 * 1000000UL);
   esp_sleep_enable_ext0_wakeup(GPIO_NUM_36, LOW);

   gpio_hold_en((gpio_num_t) M5EPD_MAIN_PWR_PIN);
   gpio_deep_sleep_hold_en();
   esp_deep_sleep_start();

   // Only reached after light sleep
   Serial.println("after sleep");
   delay(1000);
}

Not sure this is the right way as I could not find any specific way to read the touch coordinates.

felmue

Hello @cthulu

you want to check against ESP_SLEEP_WAKEUP_EXT0 as wake-up cause since the touch interrupt line (GPIO36) is setup using esp_sleep_enable_ext0_wakeup().

BTW: ESP_SLEEP_WAKEUP_TOUCHPAD is meant for an ESP32 feature where a GPIO can act as a touch sensor. See here (Which is different from the touch screen).

Thanks
Felix

cthulu

Thanks @felmue!

I will change that. Regarding reading the touch location, is that the proper way? First M5.TP.update() and then trying to clear the interrupt using M5.TP.flush()?

I am trying render some buttons on the screen and then go to deep sleep, waiting for the touch push.

cthulu

Looks like the code, with the modification you've suggested works! I can get the coordinates of the touch that lead to the wake up of the M5. Thanks!