SPICE simulation of a Temperature Control System Module implemented with a PIC16F877A. This is a module of a centralized home automation system. The temperature is measured by the sensor LM35, the setpoint and current temperature values are shown on a LCd display. The PIC drives a heating system and a ventilation system. On “winter position” of the switch, if the temperature drops below the winter setpoint temperature, the module turn on the heating system, and turn it off when the temperature exceeds the setpoint value. On “summer position”, if the temperature is higher than the summer setpoint temperature the PIC turn on the ventilation system and turn it off if the temperature drops down the setpoint value. The C source code is compiled with PIC C compiler.