touchAttachInterrupt() userfunc parameter should not be void

[ericgu]

I'm working on some code that uses the touch subsystem and the arduino HAL.

I can call touchAttachInterrupt() multiple times for different pins. The underlying code in __touchISR() knows which routine to call for a specific pin, but it doesn't pass any pin information on.

This forces me to write something like:
touchAttachInterrupt(4, Touch0Interrupt, 20);
...
touchAttachment(32, Touch9Interrupt, 20);

touchAttachInterrupt() should store the pin number away at the same time it stores the function pointer away and then pass it on the callback. That would let me write a routine like:

void MyTouchHandler(int pinNumber)
{

}

and handle all the touch pins with a single chunk of generic code.

[sansillusion]

Not sure as I'm not much of a programmer but would something like that work ? :
touchAttachInterrupt(4, TouchInterrupt(0), 20);
touchAttachment(32, TouchInterrupt(9), 20);

[ericgu]

Unfortunately, that does not work, but you did get me thinking that I can probably do something with the C++ lambda support. Something like:

int pin = 32;
touchAttachInterrupt(pin, pin{MyInterruptHandler(pin);});

assuming I have my lambda syntax correct. That's not great but it's better than what I had planned from a syntax perspective, though the overhead might be worse...

Edit: there should be brackets around the second "pin".

[ericgu]

Lambdas do work but not in the format I used; you can't pass lambdas that do captures to function pointers, so they aren't really any better than my initial implementation.

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[Leo-C]

Hi,
I believe that function esp_sleep_get_touchpad_wakeup_status() can help you.

Interrupt handler can not get a parameter indicating pin touched, but calling function above as first instruction, you'll have same information

Leonardo

[SuGlider]

New Touch API will have this function touchAttachInterruptArg(...)

/*
 * Set cycles that measurement operation takes
 * The result from touchRead, threshold and detection
 * accuracy depend on these values. Defaults are
 * 0x1000 for measure and 0x1000 for sleep.
 * With default values touchRead takes 0.5ms
 * */
void touchSetCycles(uint16_t measure, uint16_t sleep);

/*
 * Read touch pad (values close to 0 mean touch detected)
 * You can use this method to chose a good threshold value
 * to use as value for touchAttachInterrupt
 * */
uint32_t touchRead(uint8_t pin);

/*
 * Set function to be called if touch pad value falls (ESP32)
 * below the given threshold / rises (ESP32-S2/S3) by given increment (threshold). 
 * Use touchRead to determine a proper threshold between touched and untouched state
 * */
void touchAttachInterrupt(uint8_t pin, void (*userFunc)(void), uint32_t threshold);
void touchAttachInterruptArg(uint8_t pin, void (*userFunc)(void*), void *arg, uint32_t threshold);
void touchDetachInterrupt(uint8_t pin);

/*
 * Specific functions to ESP32 
 * Tells the dirver if it shall activate the ISR if the sensor is Lower or Higher than the Threshold
 * Default if Lower.
 **/
void touchInterruptSetThresholdDirection(bool mustbeLower);