NXP Semiconductors MCF51AC128ACFUE

Overview

MCF51AC128ACFUE from NXP Semiconductors (formerly Freescale) is a 32-bit ColdFire V1 microcontroller with CAN interface, 128 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, 20-channel 12-bit ADC, two SPI interfaces (one with 16-bit FIFO), dual SCI UARTs, FTM/TPM timers, CRC engine, and MCG clock generator - deployed in industrial motor control and automotive body electronics.

For engineers reviewing the MCF51AC128ACFUE datasheet, MCF51AC128ACFUE pinout, MCF51AC128ACFUE application, or MCF51AC128ACFUE equivalent, key selection criteria include CAN 2.0A/B compliance at up to 1 Mbps, 64-pin QFP thermal rating of –40°C to +85°C, 20-channel ADC with asynchronous clock support for noise reduction, and ColdFire V1 ISA_C instruction set compatibility with legacy MC9S08AC128 migration paths.

Technical Context

The MCF51AC128ACFUE implements the ColdFire V1 core with background debug module (BDM), executing ISA_C instructions at up to 50.33 MHz using internal PLL/FLL clock multiplication from crystal (1–16 MHz) or LPO sources. Its memory subsystem includes 128 KB on-chip flash with block protection and 32 KB SRAM with security lock.

Peripherals are managed via SIM and CF1_INTC, supporting concurrent operation of MSCAN (5 RX/3 TX buffers), dual SCI with 9-bit framing and break detection, SPI1 (8-bit) and SPI2 (16-bit with FIFO), and two flexible timer modules (FTM1/FTM2) with deadtime insertion, PWM synchronization, and ADC hardware triggering.

Key Specifications

Pinout & Package

64-pin QFP package (14 mm × 14 mm), RoHS-compliant, with 0.8 mm pitch and exposed thermal pad. Pin functions validated per Figure 3 and Table 4 of MCF51AC256 Rev.7 datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCF51AC128ACFUE, MCF51AC256ACFUE doubles flash capacity while maintaining pin, peripheral, and thermal compatibility - ideal for incremental firmware growth. S9KEAZ128AMLH trades CAN for USB and ARM ecosystem tooling, making it suitable only where CAN is absent from system architecture.

Availability

MCF51AC128ACFUE is available at Aetrix Electronics and suitable for industrial motor control, automotive body electronics, and smart energy metering requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MCF51AC128ACFUE 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 acquired Freescale in 2015 and maintains the ColdFire microcontroller portfolio for legacy industrial and automotive designs requiring deterministic real-time performance and long-term supply assurance.

The MCF51AC series was designed as a 32-bit upgrade path from the MC9S08AC128 8-bit MCU family, targeting cost-sensitive applications needing CAN, enhanced ADC, and scalable flash while retaining ColdFire V1 code compatibility.

FAQ

What is the maximum operating frequency of the MCF51AC128ACFUE?

The MCF51AC128ACFUE operates at up to 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 or FLL modes driven by an external crystal (1–16 MHz) or internal reference. Performance is verified per Table 16 (MCG Frequency Specifications) and Table 17 (Control Timing) in the Rev.7 datasheet. The MCF51AC128ACFUE delivers 0.76 DMIPS/MHz when executing from flash memory.

Does the MCF51AC128ACFUE support CAN 2.0B extended frames?

Yes, the MCF51AC128ACFUE's MSCAN module fully supports CAN 2.0B extended frames (29-bit identifiers) as specified in ISO 11898-1. It implements standard and extended data frames, zero-to-eight byte payloads, and programmable bit rates up to 1 Mbps. Flexible maskable identifier filters include two 32-bit extended ID filters, enabling selective reception of extended frames in multi-node networks. This capability is documented in Section 1.3.1 and Table 2 of the MCF51AC256 Rev.7 datasheet.

How many ADC channels does the MCF51AC128ACFUE have, and what is their resolution?

The MCF51AC128ACFUE features a 20-channel 12-bit successive approximation register (SAR) ADC, as confirmed in Table 1 (Device Comparison) and Section 1.3.1 of the Rev.7 datasheet. Channels support 12-, 10-, or 8-bit right-justified output formats. Conversion can be triggered manually, by timer, or automatically in continuous mode. The ADC includes an on-chip temperature sensor and supports asynchronous clocking to reduce noise coupling from digital switching - critical for precision measurement applications using the MCF51AC128ACFUE.

What debug interface does the MCF51AC128ACFUE use, and is JTAG required?

The MCF51AC128ACFUE uses a single-wire Background Debug Mode (BDM) interface via the BKGD/MS pin - no JTAG header or additional pins are required. This interface supports programming, real-time trace via the debug visibility bus (VBUS), and six hardware breakpoints (four PC, one address pair, one data). The BDM is integrated into the ColdFire V1 core and requires only one dedicated pin, simplifying PCB layout and reducing debug footprint. Full functionality is detailed in Section 1.3.1 and Table 2 of the MCF51AC256 Rev.7 datasheet.

Is the MCF51AC128ACFUE pin-compatible with other members of the MCF51AC family?

Yes, the MCF51AC128ACFUE is pin-compatible with all 64-pin QFP variants in the MCF51AC family, including MCF51AC256ACFUE and MCF51AC128CCFUE. Pin assignments match Figure 3 and Table 4 of the Rev.7 datasheet. Differences are limited to flash size (128 KB vs. 256 KB), RAM size (32 KB vs. 16 KB in non-CAN variants), and CAN presence - all implemented without altering pin function mapping. This enables direct substitution in existing 64-pin QFP layouts when upgrading firmware capacity or selecting CAN-enabled versions of the MCF51AC128ACFUE.