S12G 16-bit MCUs HVAC Control Platform Reference Solution Overview Automotive heating, ventilation and air conditioning (HVAC) systems are designed to provide a comfortable cabin driving environment while minimizing power consumption and overall load on the vehicle. This is done by taking inputs from a variety of sensors, processing those inputs with an ADC/DAC and using the data to control different types of motors. For example, stepper and DC motors are used to control the air vent flaps while DC and BLDC motors are used to control the blowers. The Freescale automotive HVAC control platform reference solution utilizes the scalable S12G 16-bit MCU family along with MC33905, MC33932 and MC33937 analog devices to drive each of these types of motors and leverages a configurable automatic climate control software algorithm providing a featurerich solution for automotive HVAC applications. The automotive HVAC control platform reference solution consists of a central control board with human-machineinterface (HMI), a motor control board, flap and blower motors. It enables the basic functions of an automotive HVAC system using temperature, light, humidity and air quality sense interfaces together with the configurable automatic climate control software algorithm to more efficiently control the vehicle climate. The LCD controlled by the S08LG MCU (optional) can display rich content for the driver including temperature, wind speed and calendar. This reference solution will reduce the overall R&D effort for customers, shorten overall time to market and can be tailored for both 12 and 24 V automotive HVAC systems. The S12G MCU is the core controller of this reference solution, offering 16 to 240 KB of flash and 20, 32, 48, 64, to 100 pin count, with full pin compatibility and maximums module reuse within the family. EEPROM on board and multiple peripheral interfaces such as CAN and LIN/SCI communications to link the main control system with the distributed motor units, SPI for analog connections and PWM signal control makes the S12G MCU ideal for automotive HVAC applications. Stepper Motor BLDC Motor DC Motor Motor Control Board Central Control Board with HMI HVAC Control Platform Reference Solution HVAC Control Platform Key Features • Three types of motor control (sensor-less BLDC, DC and stepper motor) Motor ControlControl Board Block HVAC Block Central Control Board Block Diagram HVAC HVAC Central Board Diagram RESET 12 V • Automatic climate control CAN • Supports multiple temperature zones LIN INT SBC MC33905 CAN SCI1 • 3 x 3 matrix keypad and two encoder knob inputs PWM Inputs Captures ENV Inputs ADCs • Two logic relay interfaces to compressor/ defrost module • Real-time clock and date display, adjustment for calendar Segment LCD Keypad • Up to 240 KB on-chip flash with ECC • Up to 4 KB EEPROM with ECC Fault MC9S12G240 Control SPIO GPIO (Motor Control Inputs) • Up to three serial peripheral interface modules • Precision fixed voltage reference for analog-to-digital conversion Connector to Motor Control Board GPIO Interrupts (Fault Signals) ADCs (Motor Position Feedback) SPI1 INT MC9S08LG32 Encoder Key Inputs Knob Inputs Motor Control Board Block Diagram HVAC HVAC Motor Control Board Block Diagram 5V GPIOs Connector to Motor Control Board INT Relays H-Bridge MC33932 Feedback Pre-Driver MC33937 ADCs (Status Feedback) LM5022 DCB Flap Motors (Step Motor or DC Motor) ADCs (Flap Motor Position Feedback) SPI Control 12 V LM2694 12 V MOS CTL MOSFET Bridges Current Sampling Circuit U, V, W U, V, W Blower Motor (BLDC Motor) Freescale Technology Family BlockBlock DiagramDiagram S12G S12G Family • Supporting CAN protocol 2.0 A/B • Up to three serial communication interface modules, supporting LIN communications Feedback ADCs (BLDC Status Feedback) • Up to 11 KB on-chip SRAM • Up to one multi-scalable controller area network (MSCAN) module Dead Time Unit and Protection Unit Freescale Technology • Suitable for both 12 and 24 V HVAC systems • S12 CPU core, 25 MHz bus LCD GPIOs • Extensible with touch keyboard or touch screen board S12G MCU Key Features Relays SCI1 Debug UART • Sensor interfaces for temperature, light, humidity and air quality available GPIOs SPIO • CAN and LIN communication interfaces • 4 x 37 segment LCD and adjustable backlighting PWMs VDD • Ultra-low-power mode, can be woke up by HMI or LIN/CAN bus Relay Driver GPIOs MUXOUT MSCAN (Not on GN) 10-bit ADC 12-bit ADC (GA) Up to 16-ch. GPIO LIN/SCI Up to 3 10-bit ADC 12-bit ADC (GA) Up to 16-ch. SPI Up to 3 • 1 MHz internal oscillator • On-chip voltage regulator for input supply and internal voltages 2-ch. 8-bit DAC (GA only) • This product is included in the Freescale Product Longevity program, with assured supply for a minimum of 15 years after launch Flash (ECC) (16–240 K) Debug Interrupt EP ROM 4 Byte blocks (ECC) (512–4096 B) Timers 16-bit Up to 8-ch. PWM 8/16-bit Up to 8/4-ch. Analog Comparator (GN16 thru G64 only) RAM (1024–11264 B) Note: Not all peripherals are available in all package types For more information, visit freescale.com/automotive Freescale and the Freescale logo are trademarks of Freescale Semiconductor, Inc., Reg. U.S. Pat. & Tm. Off. All other product or service names are the property of their respective owners. © 2012 Freescale Semiconductor, Inc. Document Number: S12GHVACCTLPLTFS REV 0