File content as of revision 2:1956c8e08cd3:

#include <mbed.h>
#include <mpr121.h>
DigitalOut led1(LED1);
DigitalOut led2(LED2);
DigitalOut led3(LED3);
DigitalOut led4(LED4);
// Create the interrupt receiver object on pin 26
InterruptIn interrupt(p26);
// Setup the i2c bus on pins 9 and 10
I2C i2c(p9, p10);
// Setup the Mpr121:
// constructor(i2c object, i2c address of the mpr121)
Mpr121 mpr121(&i2c, Mpr121::ADD_VSS);
 
// Key hit/release interrupt routine
void fallInterrupt() {
  int key_code=0;
  int i=0;
  int value=mpr121.read(0x00);
  value +=mpr121.read(0x01)<<8;
  // LED demo mod
  i=0;
  // puts key number out to LEDs for demo
  for (i=0; i<12; i++) {
  if (((value>>i)&0x01)==1) key_code=i+1;
  }
  led4=key_code & 0x01;
  led3=(key_code>>1) & 0x01;
  led2=(key_code>>2) & 0x01;
  led1=(key_code>>3) & 0x01;
}
 
int main() {
  interrupt.fall(&fallInterrupt);
  interrupt.mode(PullUp);
  while (1) {}
}