Introduction
The MC68HC908LJ12 is a member of the low-cost, high-performance M68HC08 Family of 8-bit microcontroller units (MCUs). The M68HC08 Family is based on the customer-specified integrated circuit (CSIC) design strategy. All MCUs in the family use the enhanced M68HC08 central processor unit (CPU08) and are available with a variety of modules, memory sizes and types, and package types.

Features
Features of the MC68HC908LJ12 include the following:
• High-performance M68HC08 architecture
• Fully upward-compatible object code with M6805, M146805, and M68HC05 Families
• Maximum internal bus frequency:
– 8-MHz at 5V operating voltage
– 4-MHz at 3.3V operating voltage
• 32-kHz crystal oscillator clock input with 32MHz internal phaselock-loop
• Optional continuous crystal oscillator operation in stop mode
• 12k-bytes user program FLASH memory with security1 feature
• 512 bytes of on-chip RAM
• Two 16-bit, 2-channel timer interface modules (TIM1 and TIM2) with selectable input capture, output compare, and PWM capability on each channel
• Real time clock (RTC) with clock, calendar, alarm, and chronograph functions. Selectable periodic interrupt requests for seconds, minutes, hours, days, 2-Hz, 4-Hz, and 100-Hz
• Serial communications interface module (SCI) with infrared (IR) encoder/decoder
• Serial peripheral interface module (SPI)
• IRQ external interrupt pin with integrated pullup
• 8-bit keyboard wakeup port with programmable pullup
• 32 general-purpose input/output (I/O) pins:
   – High current 8-mA sink capability on PTB2–PTB5
   – High current 20-mA sink capability on PTB0–PTB1
• 4/3 backplanes and static with maximum 27 frontplanes liquid crystal display (LCD) driver
• 6-channel, 10-bit successive approximation analog-to-digital converter (ADC)
• Resident routines for in-circuit programming and EEPROM emulation
• Low-power design (fully static with stop and wait modes)
• Master reset pin (with integrated pullup) and power-on reset
• Spike filter protection for EMC performance enhancement
• System protection features
   – Optional computer operating properly (COP) reset, driven by internal 64-kHz RC oscillator
   – Low-voltage detection with optional reset or interrupt
   – Illegal opcode detection with reset
   – Illegal address detection with reset
• 64-pin quad flat pack (QFP), 64-pin low-profile quad flat pack (LQFP), 52-pin low-profile quad flat pack (LQFP), and die form
• Specific features of the MC68HC908LJ12 in 52-pin LQFP are:
   – 20 general-purpose I/Os only
   – High current 8-mA sink capability on PTB2–PTB3 only
   – 4-bit keyboard wakeup port with programmable pullup
   – No serial peripheral interface module (SPI)
   – No TIM2 input capture/output compare pins
   – 4-channel analog-to-digital converter only

Features of the CPU08 include the following:
• Enhanced HC05 programming model
• Extensive loop control functions
• 16 addressing modes (eight more than the HC05)
• 16-bit Index register and stack pointer
• Memory-to-memory data transfers
• Fast 8 × 8 multiply instruction
• Fast 16/8 divide instruction
• Binary-coded decimal (BCD) instructions
• Optimization for controller applications
• Efficient C language support