MCP23s17 Blink example

Troubleshooting
21

Ah! I called the wrong method to read.

mcp2.attachInterrupt(button,change,mcp23s17::InterruptMode::FALLING);

It still doesn’t work as intended though. I cannot get it to trigger at all if i use RISING and while in CHANGE or FALLING button presses do not always toggle D7.

22

This is also not the correct function to reset the flag.

How about mcp2.digitalRead(button)?

23

Sorry! I’m having a copy paste hell day!

mcp2.digitalRead(button);

is the one i used.

24

Try this

void handler(){
  uint8_t pin = mcp2.getLastInterruptPin();
  uint8_t val = mcp2.getLastInterruptPinValue();
  digitalWrite(D7, !digitalRead(D7));
  while(mcp2.digitalRead(pin) == val); // wait till interrupt condition goes away
}

BTW, why are you setting up two ISRs handler() and change()? What’s happening in change()?

25

Looks like i am using a different Library. This one does not even have member functions you listed.

26

Yup, there are multiple MCS23… libraries, you may try others if one doesn’t give you the results you want.