// ISR - This runs every time the SA9123L pulses ISR(INT0_vect) pulse_count++;
If you require the official datasheet to write your driver, it is often archived under older part numbers. You can typically find it by searching for: sa9123l driver
For bit-perfect digital audio transport, deploying the dedicated Savitech ASIO Driver Packages overrides standard OS manipulation. // ISR - This runs every time the