NXP Semiconductors MC68HRC705KJ1CP

Overview

MC68HRC705KJ1CP from Freescale Semiconductor is a 8-bit HCMOS microcontroller based on the M68HC05 core, featuring 1240 Bytes of EPROM/OTPROM, 64 Bytes RAM, a 15-stage multifunction timer, and COP watchdog. It operates at up to 4.0 MHz at 5.0 V and supports RC oscillator configuration with internal resistor option, targeting low-cost embedded control in industrial sensors and appliance subsystems.

For engineers reviewing the MC68HRC705KJ1CP datasheet, MC68HRC705KJ1CP pinout, MC68HRC705KJ1CP application, or MC68HRC705KJ1CP equivalent, key selection criteria include its 16-pin PDIP package, software-programmable I/O pulldowns, 10-mA sink capability per pin, and support for stop/wait low-power modes without minimum clock speed requirement.

Technical Context

The MC68HRC705KJ1CP implements the M68HC05 CPU core with fully static design-no minimum clock frequency required-and integrates memory-mapped I/O registers. Its RC oscillator option enables self-contained timing without external crystal, with typical operating frequency of 4.0 MHz at 5.0 V and 25°C.

It includes a 15-stage multifunction timer supporting real-time interrupt and overflow interrupt generation, plus a Computer Operating Properly (COP) watchdog module with configurable timeout period. The device supports edge- or level-sensitive external interrupt triggering via IRQ/VPP pin and provides keyboard-scan interrupt capability on four PA pins.

Key Specifications

Pinout & Package

MC68HRC705KJ1CP is housed in a 16-pin Plastic Dual In-line Package (PDIP), Case #648, with 0.3-inch body width and 0.1-inch pin pitch - compatible with standard through-hole PCB assembly and socketing.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microcontroller applications.

Compared with MC68HC705KJ1CP and MC68HLC705KJ1CP, the MC68HRC705KJ1CP uniquely integrates an internal RC bias resistor-enabling single-resistor oscillator configuration-while maintaining full instruction and memory-map compatibility across the KJ1 family for seamless firmware porting.

Availability

MC68HRC705KJ1CP is available at Aetrix Electronics and suitable for industrial sensor nodes, home appliance control modules, small motor driver interfaces, and legacy equipment retrofits requiring stable component supply and long-term obsolescence management.

Supply support for MC68HRC705KJ1CP includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Freescale Semiconductor (now part of NXP Semiconductors) was a leading designer of embedded processors and analog/mixed-signal ICs, known for automotive, industrial, and consumer microcontrollers.

The MC68HRC705KJ1CP belongs to the M68HC05 family-designed for cost-sensitive, low-pin-count embedded control applications where integration, power efficiency, and firmware security are prioritized over high performance.

FAQ

What oscillator options does the MC68HRC705KJ1CP support?

The MC68HRC705KJ1CP supports RC oscillator configuration with internal bias resistor, enabling operation without external crystal or resonator. It also accepts external clock input. Unlike the base MC68HC705KJ1CP, it does not require an external resistor for RC timing-reducing component count. The internal oscillator delivers ~4.0 MHz at 5.0 V and 25°C, with frequency varying ±20% across voltage and temperature ranges.

Does the MC68HRC705KJ1CP have built-in debug or programming interfaces?

The MC68HRC705KJ1CP lacks dedicated debug interfaces like SWD or JTAG. Programming is performed via the IRQ/VPP pin, which accepts 12.5 V during EPROM programming cycles. Firmware is loaded using parallel programming hardware that applies VPP and controls address/data buses. No in-circuit debugging is supported-development relies on ROM emulation or external ICE tools compatible with the M68HC05 architecture.

How much user RAM and program memory does the MC68HRC705KJ1CP provide?

The MC68HRC705KJ1CP provides 64 bytes of user RAM and 1240 bytes of EPROM/OTPROM program memory, including eight bytes reserved for user interrupt vectors. This memory allocation supports compact firmware for tasks such as sensor interfacing, LED sequencing, and basic motor control-sufficient for applications with limited code complexity and no dynamic data structures.

Can the MC68HRC705KJ1CP operate from a 3.3 V supply?

No-the MC68HRC705KJ1CP is specified for 5.0 V ±10% operation only. Its electrical characteristics-including I/O drive strength, timing parameters, and internal oscillator behavior-are characterized exclusively at 5.0 V. Attempting 3.3 V operation may result in unreliable reset behavior, failed EPROM programming, or undefined CPU execution. For 3.3 V systems, consider later-generation derivatives or voltage-level translation.

What low-power modes are available on the MC68HRC705KJ1CP?

The MC68HRC705KJ1CP supports Stop, Wait, and Data-Retention modes. In Stop mode, the CPU and peripherals halt while RAM contents are preserved; wake-up occurs via RESET or IRQ. Wait mode stops the CPU but keeps the oscillator and timer running-enabling periodic wake-up. Data-Retention mode maintains RAM with minimal current draw (~1 µA), ideal for battery-backed applications. All modes require no minimum clock speed due to fully static design.