The GL518SM is a low-cost and highly integrated circuit designed in CMOS technology which serves as a hardware monitor of any microprocessor based system. The GL518SM can be used to monitor temperatures, power supply voltages and fan speeds in a PC system. By connecting to an external thermistor for remote sensing applications, the GL518SM allows more flexibility in location of the sensor. The GL518SM will generate interrupts and drive different square-like wave which allows the speaker to sound the alarm when it detects the abnormal situation. Through the I2C bus interface, the host can program the temperature trip points and query the GL518SM about the interrupt status, current temperature, voltage and fan speed.