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Add backlight control functionality for E Ink display using the touch button #9198

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Add backlight control functionality for E Ink display using the touch button #9198

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b3a9861
Add backlight control functionality for E Ink display using the touch…
viperet Jan 6, 2026
7954b35
Fix indentation in setup function for touch button initialization
viperet Jan 8, 2026
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26 changes: 26 additions & 0 deletions src/graphics/Screen.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -533,6 +533,10 @@ void Screen::handleSetOn(bool on, FrameCallback einkScreensaver)
}
}

#ifdef PIN_EINK_EN
uint32_t backlight_peek_time = 0;
#endif

void Screen::setup()
{

Expand Down Expand Up @@ -757,6 +761,18 @@ int32_t Screen::runOnce()
enabled = false;
return RUN_SAME;
}
#ifdef PIN_EINK_EN
#ifndef BACKLIGHT_TIMEOUT_MS
#define BACKLIGHT_TIMEOUT_MS 3000 // Turn off backlight after 3 seconds by default
#endif
// Turn off backlight after timeout
if (uiconfig.screen_brightness > 0 && backlight_peek_time != 0 &&
millis() - backlight_peek_time > BACKLIGHT_TIMEOUT_MS) {
digitalWrite(PIN_EINK_EN, LOW);
backlight_peek_time = 0;
uiconfig.screen_brightness = 0;
}
#endif

if (displayHeight == 0) {
displayHeight = dispdev->getHeight();
Expand Down Expand Up @@ -1771,6 +1787,16 @@ int Screen::handleInputEvent(const InputEvent *event)
showFrame(FrameDirection::PREVIOUS);
} else if (event->inputEvent == INPUT_BROKER_CANCEL) {
setOn(false);
#ifdef PIN_EINK_EN
} else if (event->inputEvent == INPUT_BROKER_BACKLIGHT) {
digitalWrite(PIN_EINK_EN, HIGH);
backlight_peek_time = millis();
uiconfig.screen_brightness = 1;
} else if (event->inputEvent == INPUT_BROKER_BACKLIGHT_TOGGLE) {
uiconfig.screen_brightness = 1 - uiconfig.screen_brightness;
digitalWrite(PIN_EINK_EN, uiconfig.screen_brightness == 0 ? LOW : HIGH);
backlight_peek_time = 0;
#endif
}
}
}
Expand Down
2 changes: 2 additions & 0 deletions src/input/InputBroker.h
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,8 @@ enum input_broker_event {
INPUT_BROKER_RIGHT = 20,
INPUT_BROKER_CANCEL = 24,
INPUT_BROKER_BACK = 27,
INPUT_BROKER_BACKLIGHT = 28,
INPUT_BROKER_BACKLIGHT_TOGGLE = 29,
INPUT_BROKER_USER_PRESS,
INPUT_BROKER_ALT_PRESS,
INPUT_BROKER_ALT_LONG,
Expand Down
5 changes: 5 additions & 0 deletions src/main.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1052,6 +1052,10 @@ void setup()
BaseType_t higherWake = 0;
mainDelay.interruptFromISR(&higherWake);
};
#if defined(TTGO_T_ECHO) && defined(PIN_EINK_EN)
touchConfig.singlePress = INPUT_BROKER_BACKLIGHT;
touchConfig.longPress = INPUT_BROKER_BACKLIGHT_TOGGLE;
#else
touchConfig.singlePress = INPUT_BROKER_NONE;
touchConfig.longPress = INPUT_BROKER_BACK;
#if defined(TTGO_T_ECHO_PLUS) && defined(PIN_EINK_EN)
Expand All @@ -1071,6 +1075,7 @@ void setup()
}
touchBacklightActive = false;
};
#endif
#endif
TouchButtonThread->initButton(touchConfig);
#endif
Expand Down