Try adding #include "application.h"
You also should use the correct I2C pins on the Photon (D0/D1).
And as there is a parallel thread I’ll repeat it should be
volatile int isr_flag = 0;
Try adding #include "application.h"
You also should use the correct I2C pins on the Photon (D0/D1).
And as there is a parallel thread I’ll repeat it should be
volatile int isr_flag = 0;