ESP32-P4 eval board: Sleep with low power, but keep touch (of screen) active
Posted: Sat Oct 19, 2024 4:08 pm
Hi there,
I've managed so far to program an SSE client with lvgl ui, which works fine, but draws ca. 780 mA of current from a 5V source. I'd like to realize a power save mode for this, meaning the screen is dark, all peripherals are powered down _except_ the touch function of the screen, i.e. the int_tp signal from it, to be then used as a wake-up source.
Only switching off the LCD backlight leads to 270 mA, but powering down some more parts would be nice.
However, if I enter light sleep (not even deep sleep), the int_tp signal stops functioning. There is some reaction, but the pin level is 0V (instead of 3V when functioning) , with 0.2uS Spikes of 3V.
Looking at the board schematics hasn't helped me - I don't understand how I could keep the capacitive touch (interrupt) working or powered up. Would it be sufficient to keep the I2C bus running in sleep mode? Or can I somehow keep the power supply for the touch part active and it would work?
Any hints or help would be appreciated!
Thanks,
Max
I've managed so far to program an SSE client with lvgl ui, which works fine, but draws ca. 780 mA of current from a 5V source. I'd like to realize a power save mode for this, meaning the screen is dark, all peripherals are powered down _except_ the touch function of the screen, i.e. the int_tp signal from it, to be then used as a wake-up source.
Only switching off the LCD backlight leads to 270 mA, but powering down some more parts would be nice.
However, if I enter light sleep (not even deep sleep), the int_tp signal stops functioning. There is some reaction, but the pin level is 0V (instead of 3V when functioning) , with 0.2uS Spikes of 3V.
Looking at the board schematics hasn't helped me - I don't understand how I could keep the capacitive touch (interrupt) working or powered up. Would it be sufficient to keep the I2C bus running in sleep mode? Or can I somehow keep the power supply for the touch part active and it would work?
Any hints or help would be appreciated!
Thanks,
Max