PIC16F639 Microcontroller Overview
The PIC16F639 is a suitable microcontroller for bidirectional communications, remote passive keyless entry and low-frequency sensing applications. The device includes a PIC16F636 microcontroller and a three channel Low-Frequency (LF) front-end device in a single 20-pin SSOP package. These two devices are internally connected via the SPI? interface.
PIC16F639, KeeLoq, Passive Keyless Entry Transponder and Systems, Analog Front-End,Bidirectional Communication