Introduction
The MC68HC908QY4 is a member of the low-cost, high-performance M68HC08 Family of 8-bit microcontroller units (MCUs). The M68HC08 Family is a Complex Instruction Set Computer (CISC) with a Von Neumann architecture. 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 include:
• High-performance M68HC08 CPU core
• Fully upward-compatible object code with M68HC05 Family
• 5-V and 3-V operating voltages (VDD)
• 8-MHz internal bus operation at 5 V, 4-MHz at 3 V
• Trimmable internal oscillator
– 3.2 MHz internal bus operation
– 8-bit trim capability
– ± 25% untrimmed
– ± 5% trimmed
• Auto wake-up from STOP capability
• Configuration (CONFIG) register for MCU configuration options, including:
– Low-voltage inhibit (LVI) trip point
• In-system FLASH programming
• FLASH security(1)
• On-chip in-application programmable FLASH memory (with
internal program/erase voltage generation)
– MC68HC908QY4 and MC68HC908QT4 —4096 bytes
– MC68HC908QY2, MC68HC908QY1, MC68HC908QT2, and MC68HC908QT1 —1536 bytes
• 128 bytes of on-chip random-access memory (RAM)
• 2-channel, 16-bit timer interface module (TIM)
• 4-channel, 8-bit analog-to-digital converter (ADC) on MC68HC908QY2, MC68HC908QY4, MC68HC908QT2, and MC68HC908QT4
• 5 or 13 bidirectional input/output (I/O) lines and one input only:
– Six shared with keyboard interrupt function and ADC
– Two shared with timer channels
– One shared with external interrupt (IRQ)
– Eight extra I/O lines on 16-pin package only
– High current sink/source capability on all port pins
– Selectable pullups on all ports, selectable on an individual bit basis
– Three-state ability on all port pins
• 6-bit keyboard interrupt with wakeup feature (KBI)
• Low-voltage inhibit (LVI) module features:
– Software selectable trip point in CONFIG register
• System protection features:
– Computer operating properly (COP) watchdog
– Low-voltage detection with reset
– Illegal opcode detection with reset
– Illegal address detection with reset
• External asynchronous interrupt pin with internal pullup (IRQ) shared with general-purpose input pin
• Master asynchronous reset pin (RST) shared with general-purpose input/output (I/O) pin
• Power-on reset
• Internal pullups on IRQand RSTto reduce external components
• Memory mapped I/O registers
• Power saving stop and wait modes
• MC68HC908QY4, MC68HC908QY2, and MC68HC908QY1 are available in these packages:
– 16-pin plastic dual in-line package (PDIP)
– 16-pin small outline integrated circuit (SOIC) package
– 16-pin thin shrink small outline package (TSSOP)
• MC68HC908QT4, MC68HC908QT2, and MC68HC908QT1 are available in these packages:
– 8-pin PDIP
– 8-pin SOIC