The X40420/21 combines power-on reset control, watchdog timer, supply voltage supervision, and secondary supervision, manual reset, and Block LockTM protect serial EEPROM in one package. This combination lowers system cost, reduces board space requirements, and increases reliability. Applying voltage to VCC activates the power on reset circuit which holds RESET/RESET active for a period of time. This allows the power supply and system oscillator to stabilize before the processor can execute code.