HC05KJ

HC05KJ Microcontroller Technical Summary

Overview

The HC05KJ is a versatile 8-bit microcontroller from the Motorola HC05 family, designed for embedded control applications. It combines a high-performance CPU core with integrated memory and a rich set of peripherals, making it suitable for cost-sensitive, low-power applications. The device features robust noise immunity and flexible clocking options, including support for crystal, ceramic resonator, or RC oscillator configurations.

Key Features

• Processor Core: 8-bit HC05 architecture with 4.0 MHz maximum operating frequency at 5V
• Memory:
  • 1240 bytes of EPROM/OTPROM (including 8 bytes for user vectors)
  • 64 bytes of user RAM
• I/O Capabilities:
  • 10 bidirectional I/O pins with 10 mA sink capability on all pins
  • 5.5 mA source capability on 6 I/O pins
  • Software-programmable pull-downs on all I/O pins
  • Keyboard scan functionality with selectable interrupt on 4 I/O pins
• Peripheral Modules:
  • 15-stage multifunction timer
  • Computer Operating Properly (COP) watchdog timer
  • Configurable external interrupt module (edge/level sensitive)
• Low Power Modes: Stop and Wait modes with data retention capability
• Oscillator Options: Supports crystal, ceramic resonator, or RC oscillator configurations

Applications

The HC05KJ is well-suited for a variety of embedded control applications, including:

• Consumer electronics
• Appliance control
• Industrial control systems
• Automotive electronics
• Security systems
• Keyboard interfaces
• Sensor monitoring and control

Electrical Characteristics

Absolute Maximum Ratings

• Supply Voltage (VDD): -0.3V to +7.0V
• Input Voltage (any pin): -0.3V to VDD + 0.3V
• Operating Temperature Range: -40°C to +85°C
• Storage Temperature Range: -55°C to +150°C

DC Electrical Characteristics (5.0V operation)

• Operating Voltage: 4.5V to 5.5V
• Input High Voltage: 0.7VDD min
• Input Low Voltage: 0.2VDD max
• Output High Voltage: VDD - 0.8V min (5.5 mA load)
• Output Low Voltage: 0.4V max (10 mA sink)
• Supply Current (4 MHz operation): 5 mA typical
• Wait Mode Current: 1 mA typical
• Stop Mode Current: 10 μA typical

Timing Characteristics

• Instruction Cycle Time: 1 μs at 4 MHz
• External Interrupt Pulse Width: 100 ns min
• Reset Pulse Width: 1.5 μs min
• Timer Input Frequency: 2 MHz max

Package Information

The HC05KJ is available in multiple package options:

• 20-pin Plastic Dual In-line Package (PDIP):
  • Dimensions: 25.4mm x 6.35mm
  • Pin spacing: 2.54mm
• 20-pin Small Outline Package (SOIC):
  • Dimensions: 12.8mm x 7.5mm
  • Pin spacing: 1.27mm

Memory Organization

The HC05KJ features a straightforward memory map:

• 0000-003F: 64 bytes RAM
• 0040-007F: I/O and peripheral registers
• 0080-07FF: 1240 bytes EPROM/OTPROM (user program space)
• 07F8-07FF: 8 bytes reserved for user vectors

Peripheral Modules

Parallel I/O Ports

The device features two configurable I/O ports:

• Port A: 6 general-purpose I/O pins with enhanced drive capability
• Port B: 4 general-purpose I/O pins with keyboard interrupt functionality

Multifunction Timer

The 15-stage timer module includes:

• Programmable prescaler
• Input capture capability
• Output compare functionality
• Timer overflow interrupt

Computer Operating Properly (COP) Watchdog

The COP module provides:

• Programmable timeout period
• Reset generation on system failure
• Low-power mode operation control

Development Support

The HC05KJ is supported by:

• In-circuit programming capability for OTP versions
• Full-featured assembler and C compiler toolchains
• Emulation and debugging tools
• Evaluation boards for rapid prototyping

Ordering Information

The device is available in several variants:

• MC68HC705KJ1: Standard version with EPROM
• MC68HRC705KJ1: RC oscillator version
• MC68HLC705KJ1: Low-voltage (3.3V) version

Each variant is available in both PDIP and SOIC packages with commercial (0°C to +70°C) and industrial (-40°C to +85°C) temperature ranges.