NXP Semiconductors MCF51AC256ACFUE

Overview

MCF51AC256ACFUE from NXP Semiconductors (formerly Freescale) is a 32-bit ColdFire V1 microcontroller with CAN interface, 256 KB flash, 32 KB SRAM, and 64-pin QFP package operating up to 50.33 MHz at 2.7–5.5 V. It integrates dual analog comparators, 24-channel 12-bit ADC, two FTM modules, SCI/SCI2, SPI1/SPI2, IIC, CRC, and MCG for industrial motor control and automotive body electronics.

For engineers reviewing the MCF51AC256ACFUE datasheet, MCF51AC256ACFUE pinout, MCF51AC256ACFUE application, or MCF51AC256ACFUE equivalent, key selection considerations include CAN 2.0A/B compliance, –40°C to +85°C temperature grade, 64-pin QFP mechanical compatibility, and ColdFire V1 ISA_C instruction set performance (0.76 DMIPS/MHz from flash).

Technical Context

The MCF51AC256ACFUE implements the ColdFire V1 core with background debug module (BDM), supporting single-wire real-time debugging and 6 hardware breakpoints. Its multipurpose clock generator (MCG) combines FLL/PLL with trimmable internal reference (0.2% resolution) and supports crystal (1–16 MHz) or LPO sources for COP/RTI.

Peripheral integration includes MSCAN with five receive buffers, three prioritized transmit buffers, programmable bit rate up to 1 Mbps, and bus-off recovery; plus dual FTM modules (FTM1: 6 channels, FTM2: 2 channels) supporting edge- and center-aligned PWM, deadtime insertion, and ADC hardware triggering.

Key Specifications

Pinout & Package

Package: 64-pin QFP, 14 mm × 14 mm, lead-free (RoHS-compliant), thermal pad not present.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCF51AC256AVFUE, the MCF51AC256ACFUE trades extended temperature range for lower cost and qualification tier; compared with MCF51AC128ACFUE, it doubles flash capacity while retaining identical peripheral set and CAN capability - enabling scalable firmware development across product tiers.

Availability

MCF51AC256ACFUE is available at Aetrix Electronics and suitable for industrial motor control, automotive body electronics, medical infusion pumps, and energy metering interfaces requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MCF51AC256ACFUE 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 is a global semiconductor leader delivering secure, connected, and intelligent solutions for automotive, industrial, IoT, mobile, and communication infrastructure markets.

The MCF51AC256ACFUE belongs to NXP's ColdFire microcontroller family, designed specifically for cost-sensitive, real-time embedded applications requiring CAN connectivity, analog integration, and deterministic execution - bridging the performance gap between 8-bit MCUs and higher-end 32-bit processors.

FAQ

What is the maximum operating frequency of the MCF51AC256ACFUE?

The MCF51AC256ACFUE operates at a maximum core frequency of 50.33 MHz across its full 2.7–5.5 V supply range and –40°C to +85°C temperature grade. This frequency is achieved using the MCG's PLL mode with an external 8 MHz crystal; actual system clock depends on MCG configuration and is verified in Section 2.10 of the datasheet. The MCF51AC256ACFUE delivers 0.76 DMIPS per MHz when executing from flash memory.

Does the MCF51AC256ACFUE include a CAN controller?

Yes, the MCF51AC256ACFUE includes a fully integrated MSCAN module compliant with CAN 2.0A/B protocol, supporting standard and extended frames, programmable bit rates up to 1 Mbps, five receive buffers with FIFO, and three prioritized transmit buffers. The CAN signals TxCAN (PTA0) and RxCAN (PTA1) are dedicated pins requiring an external CAN transceiver for physical layer interfacing.

What package type and pin count does the MCF51AC256ACFUE use?

The MCF51AC256ACFUE uses a 64-pin QFP package measuring 14 mm × 14 mm with gull-wing leads and RoHS-compliant lead-free finish. This package is mechanically and electrically identical to the 64-pin LQFP variant (MCF51AC256AVPUE), differing only in lead profile and thermal characteristics - both share identical pinout and footprint compatibility per Figure 3 of the datasheet.

How much flash and SRAM memory does the MCF51AC256ACFUE provide?

The MCF51AC256ACFUE integrates 256 KB of on-chip flash memory and 32 KB of static RAM (SRAM). Flash supports read/program/erase operations across the full operating voltage (2.7–5.5 V) and temperature (–40°C to +85°C) range, with block protection features. SRAM is fully accessible at CPU clock speed and includes security circuitry to prevent unauthorized access to stored variables and stack data.

Is the MCF51AC256ACFUE pin-compatible with other members of the MCF51AC256 series?

Yes, the MCF51AC256ACFUE is pin-compatible with all 64-pin variants in the MCF51AC256 series, including MCF51AC256AVFUE (105°C grade) and MCF51AC256BVFUE (CAN-disabled version). Pin functions, electrical characteristics, and mechanical footprint are identical; only temperature rating and CAN enablement differ. Firmware developed for MCF51AC256ACFUE runs unchanged on MCF51AC256AVFUE, enabling seamless thermal grade upgrades.