DESCRIPTION

The IN1232 MicroMonitor Chip monitors three vital conditions for a microprocessor: power supply, software execution, and external override. First, a precision temperature–compensated reference and comparator circuit monitors the status of VCC. When an out–of–tolerance condition occurs, an internal power fail signal is generated which forces reset to the active state. When VCC returns to an in–tolerance condition, the reset signals are kept in the active state for a minimum of 250 ms to allow the power supply and processor to stabilize.

The second function the IN1232 performs is pushbutton reset control. The IN1232 debounces the pushbutton input and guarantees an active reset pulse width of 250 ms minimum. The third function is a watchdog timer. The IN1232 has an internal timer that forces the reset signals to the active state if the strobe input is not driven low prior to time–out. The watchdog timer function can be set to operate on time–out settings of approximately 150 ms, 600 ms, and 1.2 seconds.

FEATURES

□ Halts and restarts an out–of–control microprocessor

□ Holds microprocessor in check during power transients

□ Automatically restarts microprocessor after power failure

□ Monitors pushbutton for external override

□ Accurate 5 or 10 microprocessor power supply monitoring

□ Eliminates the need for discrete components