Introduction
The MC68HC05E1 is a low-cost introduction to the M68HC05 Family of microcontrollers (MCUs). The HC05 CPU core has been enhanced with a 15-stage multi-functional timer and programmable phase-locked loop. The MCU is available in a 28-pin package, and has two 8-bit I/O ports and one 4-bit I/O port. The 8 Kbyte memory map includes 368 bytes of RAM and 4096 bytes of user ROM.

Features
Features of the MC68HC05E1 include:
• Low cost
• HC05 Core
• 28-pin package
• On-Chip Oscillator (Crystal or Ceramic Resonator)
• Phase-Locked Loop (PLL) Synthesizer with Programmable Speed
• 4112 Bytes of User ROM (including 16 Bytes of User Vectors)
• 368 Bytes of On-Chip RAM
• 15-Stage Multi-functional Timer with Programmable Input
• Real Time Interrupt Circuit
• COP Watchdog Timer Mask Option
• Custom Periodic Interrupt Circuit
• 20 Bidirectional I/O Lines
• Single-Chip Mode
• Self-Check Mode
• Power Saving STOP and WAIT Modes
• Edge-Sensitive or Edge- and Level-Sensitive Interrupt Trigger Mask Option
• STOP Instruction Disable Mask Option
• Illegal Address Reset