CAT1161/2 is a complete memory and supervisory microcontroller based system solution. Serial EEPROM memory (16K) with hardware memory write protection, with Brown's system power monitor out protection and a watchdog timer integrated in low power CMOS technology. The memory interface is through the I2C bus. A 1.6 second watchdog circuit returns the system to a known good state if a software or hardware failure halts or "hangs" the system. The CAT1161 watchdog monitors the SDA line, making extra PC board traces unnecessary. The lower cost CAT1162 does not have a watchdog timer. Power monitoring and reset circuitry protects the memory and system controller against power-down conditions during power-up/power-down. Five reset threshold voltages support 5V, 3.3V and 3V systems. If the supply voltage is out of tolerance the reset signal becomes active, preventing the system microcontroller, ASIC or peripheral from operating. The reset signal becomes inactive, typically 200MS after the power supply voltage level exceeds the reset threshold. With both active high and low reset signals, interfacing microcontrollers and other ICs is very simple. Additionally, the reset pin can be used as a debounce button to input the manual reset function. CAT1161/2 memory with a 16-byte page. Additionally, hardware data protection provides a write-protect pin WP and is detected by the VCC circuit to prevent writing to memory whenever VCC falls below the reset threshold or until VCC reaches the power-on reset threshold. Available packages include an 8-pin DIP and surface mount, 8-pin SO package.