Car door module description

AN2334

6/22

The microcontroller is the ST72F561, a member of the ST7 microcontroller family, designed

for mid-range applications with CAN (Controller Area Network) and LIN (Local Interconnect

Network) interfaces. It is based on an industry standard 8-bit core, featuring an enhanced

instruction set. The enhanced instruction set and addressing modes of the ST7 offer both

power and flexibility to software developers, enabling the design of highly efficient and

compact application codes. In addition to standard 8-bit data management, all ST7

microcontrollers feature true bit manipulation, 8x8 unsigned multiplication and indirect

addressing modes.

The voltage regulator is the L4979 which offers high precision output voltage and a

programmable watchdog timer with an external capacitor. The programmable watchdog

timer allows microcontroller auto-recovery from software runaway failures.

The L9638 performs LIN-bus interface functions between the protocol handler in the

microcontroller and the physical bus in automotive applications. It has a Sleep mode that

allows the lowest current consumption of the transceiver. It is possible to wake up the

transceiver through LIN-bus, Enable input or Wake-up input.

The new VNH2SP30 window power bridge driver provides a smooth and fully-protected

motor drive via 20 kHz PWM. A current sense (CS) output is used to monitor motor torque

that provides an antitrap function via the ADC inputs of the microcontroller.

Finally, the L9950 actuator driver controls mirror adjustment and fold-in/-out, as well as an

advanced locking system, driving the door latch and the dead bolt motor. Five intrinsic high-

side drivers are available to control various lamps or LEDs, including the mirror defroster,

and sophisticated diagnostic algorithms allow digital and analog load status to be monitored

by reading fold, lock motors and defroster currents.