These devices combine four popular functions, Poweron
Reset Control, Watchdog Timer, Supply Voltage
Supervision, and Block Lock Protect Serial EEPROM
Memory in one package. This combination lowers system
cost, reduces board space requirements, and
increases reliability.
Applying power to the device activates the power-on
reset circuit which holds RESET/RESET active for a
period of time. This allows the power supply and oscillator
to stabilize before the processor can execute code.
The Watchdog Timer provides an independent protection
mechanism for microcontrollers. When the microcontroller
fails to restart a timer within a selectable time out
interval, the device activates the RESET/RESET signal.
The user selects the interval from three preset values.
Once selected, the interval does not change, even after
cycling the power.
The device’s low VCC detection circuitry protects the
user’s system from low voltage conditions, resetting
the system when VCC falls below the minimum VCC
trip point. RESET/RESET is asserted until VCC returns
to proper operating level and stabilizes. Five industry
standard VTRIP thresholds are available, however,
Intersil’s unique circuits allow the threshold to be reprogrammed
to meet custom requirements or to fine-tune
the threshold for applications requiring higher precision.