DS1238

The DS1238 MicroManager provides all the necessary functions for power supply monitoring, reset control, and memory backup in microprocessor-based systems. A precise internal voltage reference and comparator circuit monitor power supply status. When an out-of-tolerance condition occurs, the microprocessor reset and power-fail outputs are forced active, and static RAM control unconditionally write protects external memory. The DS1238 also provides early warning detection of a user-defined threshold by driving a non-maskable interrupt. External reset control is provided by a pushbutton reset debounce circuit connected to the RST pin. An internal watchdog timer can also force the reset outputs to the active state if the strobe input is not driven low prior to watchdog timeout. Oscillator control pins OSCSEL and OSCIN provide either external or internal clock timing for both the reset pulse width and the watchdog timeout period. The Watchdog Status and Reset Voltage Threshold are provided via WDS and RVT , respectively. A block diagram of the DS1238 is shown in Figure 1.