NXP Semiconductors MC68HC705C9ACP

Overview

MC68HC705C9ACP from NXP (formerly Freescale) is a 8-bit HCMOS EPROM-based microcontroller in the M68HC05 family, featuring 15,932 bytes of user EPROM, 352 bytes of RAM, a 16-bit capture/compare timer, SCI and SPI serial interfaces, and COP watchdog with clock monitor - used in legacy industrial control, appliance timing, and embedded sensor interface applications.

For engineers reviewing the MC68HC705C9ACP datasheet, MC68HC705C9ACP pinout, MC68HC705C9ACP application, or MC68HC705C9ACP equivalent, key selection considerations include its dual-configuration capability (C9A/C12A), 40-pin DIP package, 3.0–5.5 V single-supply operation, EPROM security feature, and software-programmable mask option registers for I/O and interrupt behavior.

Technical Context

The MC68HC705C9ACP implements the M68HC05 CPU core with accumulator, index register, stack pointer, and condition code register. It supports six addressing modes and includes a boot ROM (239 bytes) for EPROM programming support via bootloader mode.

Its memory-mapped I/O architecture provides 31 bidirectional I/O lines across Ports A–D, with Port C7 offering high-current sink/source capability. The device supports two low-power modes - Wait and Stop - and integrates on-chip oscillator circuitry with external crystal connections at OSC1/OSC2.

Key Specifications

Pinout & Package

MC68HC705C9ACP is housed in a 40-pin Plastic Dual In-Line Package (PDIP), Case 711-03, with 0.6-inch body width and 0.1-inch lead pitch - compatible with standard through-hole PCB assembly and socketing for development and legacy replacement.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC68HC705C9ACP, the MC68HC705P6ACP offers lower integration and smaller footprint but sacrifices SPI and memory capacity, while the MC68HC705B16CP adds EEPROM and QFP packaging at the cost of higher unit price and different layout requirements.

Availability

MC68HC705C9ACP is available at Aetrix Electronics and suitable for industrial timer control, appliance motor interface, and legacy sensor data aggregation requiring stable component supply and long-term obsolescence support.

Supply support for MC68HC705C9ACP 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

NXP Semiconductors (formerly Freescale Semiconductor) is a global leader in secure connectivity solutions for automotive, industrial, and IoT applications, with deep heritage in 8-bit microcontroller innovation.

The MC68HC705C9ACP belongs to the M68HC05 family - designed specifically for cost-sensitive, reliability-critical embedded control in appliances, industrial equipment, and legacy instrumentation where EPROM programmability and low-power operation are essential.

FAQ

What is the maximum operating frequency of the MC68HC705C9ACP?

The MC68HC705C9ACP supports an external crystal or resonator up to 4 MHz, yielding a maximum internal bus frequency of 2 MHz (via on-chip divide-by-two). This frequency is specified under 5.0 V operation per Electrical Characteristics section 12.7; at 3.3 V, max crystal frequency is 2 MHz for reliable timing compliance.

Does the MC68HC705C9ACP support in-circuit programming?

No, the MC68HC705C9ACP contains one-time-programmable EPROM and requires UV-erasable windowed packages or dedicated EPROM programmers. It does not support ISP or flash reprogramming. Programming occurs pre-deployment using the bootloader mode and PROG register described in Appendix A.

How is the MC68HC705C9ACP configured for C9A vs. C12A operation?

The MC68HC705C9ACP uses two EPROM-based Mask Option Registers: C12MOR ($3FF1) selects C12A features (STOP disable, COP enable), and C9A option register ($3FDF) enables software control of IRQ sensitivity and memory mapping. Configuration is set during EPROM programming and locked at power-up.

What are the voltage level requirements for the MC68HC705C9ACP's I/O pins?

All I/O pins on the MC68HC705C9ACP are CMOS-compatible and tolerate input voltages from VSS to VDD. Outputs swing rail-to-rail (VSS to VDD) under specified load conditions. Input thresholds are approximately 0.3×VDD (low) and 0.7×VDD (high), consistent with HCMOS logic families.

Is the MC68HC705C9ACP RoHS compliant?

The MC68HC705C9ACP was originally manufactured prior to RoHS Directive 2002/95/EC enforcement. While later second-sourced versions may carry RoHS markings, the original Freescale 40-pin PDIP variant (MC68HC705C9ACP) is exempt under RoHS Annex III - category 7(a) for "electrical and electronic components for industrial monitoring and control instruments".