Hello,
I have a problem handling external Interrupts. I want to address a keyboard that uses the I2C PCF8574 as bus expansion IC. This IC generates an interrupt if a key is pressed. The processor jumps to the interruptroutine and i read out the value of the PCF8574. That was my idea.
If i compile and link the code, i get the warning

"MULTIPLE Function call PCF8574_routine CALLER 1:Startup
CALLER 2:EXT_INTERRUPT".

I don't know if that's the correct warning, but it's something like that. If the code is running with the monitorprogram, i only get rubish from the keyboard.
I have tried to use the IRQ only to generate a flag, that a key was pressed and handled the reading from PCF8574 in my main loop. Then it is working.

can anybody help?
best regards, Markus