NXP Semiconductors MC68HC705P6ACP

Overview

MC68HC705P6ACP from Freescale Semiconductor is a 5 V, 8-bit EPROM-based microcontroller featuring an M68HC05 CPU core, 4672 bytes of user EPROM, 176 bytes of on-chip RAM, a 4-channel 8-bit A/D converter, and a 16-bit timer with input capture and output compare. It delivers embedded control in cost-sensitive industrial sensors and appliance motor interfaces requiring low-power operation and analog signal acquisition.

For engineers reviewing the MC68HC705P6ACP datasheet, MC68HC705P6ACP pinout, MC68HC705P6ACP application, or MC68HC705P6ACP equivalent, key selection factors include its 28-pin PDIP package, COP watchdog timer configurability via mask option register, SIOP serial interface timing (OSC/8–64), and EPROM security lockout capability for firmware protection.

Technical Context

The MC68HC705P6ACP implements a static CMOS M68HC05 CPU core operating at up to 2.1 MHz bus frequency (derived from OSC/2), with instruction set compatibility across the HC05 family. Its memory architecture integrates 4672 bytes of one-time-programmable EPROM, 239-byte bootloader ROM, and 176-byte SRAM - all mapped into a unified 64 KB address space with dedicated I/O register pages.

Peripheral integration includes a 4-channel 8-bit ratiometric A/D converter with internal reference support (VREFH), a 16-bit timer supporting both input capture (TCAP) and output compare (TCMP), and a synchronous serial I/O port (SIOP) with programmable MSB/LSB-first mode and selectable clock dividers (OSC/8, /16, /32, /64).

Key Specifications

Pinout & Package

MC68HC705P6ACP is housed in a 28-pin Plastic Dual In-Line Package (PDIP), Case 710, with 0.6-inch body width and 0.1-inch lead pitch. Pin 1 is marked by a notch or dot; pins are numbered counter-clockwise from pin 1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit microcontroller applications.

Compared with MC68HC705P6CDW and MC68HC705P9ACPE, the MC68HC705P6ACP offers lowest-cost through-hole implementation for legacy designs where EPROM size and ambient temperature limits (0°C to +70°C) are sufficient.

Availability

MC68HC705P6ACP is available at Aetrix Electronics and suitable for industrial sensor nodes, home appliance controllers, and legacy automotive subsystems requiring stable component supply and long-term obsolescence management.

Supply support for MC68HC705P6ACP 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 the 68HC05 and 68HC11 microcontroller families.

The MC68HC705P6ACP belongs to the M68HC05 microcontroller product line, engineered for cost-sensitive, low-power embedded control in appliances, industrial equipment, and automotive body electronics.

FAQ

What is the maximum operating frequency of the MC68HC705P6ACP?

The MC68HC705P6ACP operates with a maximum oscillator frequency of 4.2 MHz, yielding a 2.1 MHz internal bus clock (OSC/2). This frequency is specified under 5.0 V ±10% supply and 0°C to +70°C ambient conditions per Chapter 14 Electrical Specifications. Exceeding this limit may cause timing violations in the SIOP, timer, or A/D subsystems.

Does the MC68HC705P6ACP support in-system programming?

Yes, the MC68HC705P6ACP supports in-system programming via its built-in 239-byte bootloader ROM. Using the SIOP interface and a host controller, users can reprogram the 4672-byte EPROM without removing the device from the target board - provided VPP is supplied to the IRQ pin during programming cycles.

How is the A/D converter referenced on the MC68HC705P6ACP?

The MC68HC705P6ACP's 4-channel 8-bit A/D converter uses a ratiometric architecture referenced to the VREFH pin (PC7). When VREFH is unconnected, the converter defaults to VDD as reference. This design allows direct interfacing with resistive sensors (e.g., thermistors) without external precision references.

Can the MC68HC705P6ACP generate PWM signals?

Yes, the MC68HC705P6ACP can generate hardware-timed PWM using its 16-bit timer and TCMP pin. By configuring the timer in output compare mode and toggling TCMP on match events, users achieve precise duty-cycle control - commonly used for fan speed regulation or LED dimming in applications leveraging PC0/PC1 high-current outputs.

What power-saving modes does the MC68HC705P6ACP offer?

The MC68HC705P6ACP provides three low-power modes: WAIT (CPU halted, peripherals active), HALT (CPU and most peripherals halted, RAM retained), and STOP (all clocks stopped, <10 μA current draw, wake on IRQ or RESET). These are invoked via WAIT, HALT, and STOP instructions and configured via the Mask Option Register.