Datasheet

MC68HC812A4 Data Sheet, Rev. 7
Freescale Semiconductor 17
Chapter 1
General Description
1.1 Introduction
The MC68HC812A4 microcontroller unit (MCU) is a 16-bit device composed of standard on-chip
peripheral modules connected by an intermodule bus. Modules include:
• 16-bit central processor unit (CPU12)
• Lite integration module (LIM)
• Two asynchronous serial communications interfaces
(SCI0 and SCI1)
• Serial peripheral interface (SPI)
• Timer and pulse accumulator module
• 8-bit analog-to-digital converter (ATD)
• 1-Kbyte random-access memory (RAM)
• 4-Kbyte electrically erasable, programmable read-only memory (EEPROM)
• Memory expansion logic with chip selects, key wakeup ports, and a phase-locked loop (PLL)
1.2 Features
Features of the MC68HC812A4 include:
• Low-power, high-speed M68HC12 CPU
• Power-saving stop and wait modes
•Memory:
– 1024-byte RAM
– 4096-byte EEPROM
– On-chip memory mapping allows expansion to more than 5-Mbyte address space
• Single-wire background debug
mode
• Non-multiplexed address and data buses
• Seven programmable chip-selects with clock stretching (expanded modes)
• 8-channel, enhanced 16-bit timer with programmable prescaler:
– All channels configurable as input capture or output compare
– Flexible choice of clock source
• 16-bit pulse accumulator
• Real-time interrupt circuit
• Computer operating properly (COP) watchdog
• Clock monitor
• Phase-locked loop (PLL)