The S12HY automotive HVAC reference design replaces mechanical switches used for vent positions, blower speed and temperature control with an interactive LCD-based system for longevity and robustness.
This HVAC control system offers a capacitive touch pad interface (controlled through proximity capacitive touch sensor), an IR remote control (provided for the ease of rear-seat passengers) and micro-switches. It drives the actuators and blower motor with the help of a robust H-bridge and intelligent high-current switch. The system provides safety features such as motor stall detection, motor jams/shorting and open load.
The MC9S12HY64 MCU is capable of driving 160 segmented glass which displays the car cabin temperature, date and time thus eliminating the need of separate displays for these readings. Freescale has a full portfolio of automotive HVAC control system reference designs for four-wheeler applications.
- LCD-based graphics interface
- Automatic climate control
- Control for airflow (face, foot, defrost, face & defrost and face & foot) directions using actuator motors
- Control for defogger using actuator motor
- Control for recirculation using actuator motor
- 5-level control for blower speed using PMDC motor
- 9-level control for cooling/warming using actuator motor
- Car cabin temperature display
- Real time clock display and adjustment
- Date display and adjustment
- IR remote interface
- 8 touch pad interface
- 8 push button interface
- Low power mode interfaced through ignition