NXP Semiconductors MCF51AC256ACPUER

Overview

MCF51AC256ACPUER from NXP Semiconductors (formerly Freescale) is a 32-bit ColdFire V1 microcontroller with CAN interface, 256 KB flash, 32 KB SRAM, and 80-pin LQFP package. It operates up to 50.33 MHz at 2.7–5.5 V, integrates dual analog comparators, 24-channel 12-bit ADC, two FTM modules, and supports real-time debugging via single-wire BDM - deployed in automotive body control modules requiring deterministic CAN messaging and mixed-signal I/O.

For engineers reviewing the MCF51AC256ACPUER datasheet, MCF51AC256ACPUER pinout, MCF51AC256ACPUER application, or MCF51AC256ACPUER equivalent, key selection criteria include CAN 2.0A/B compliance, 80-pin LQFP mechanical compatibility, V1 ColdFire ISA_C instruction set support, on-chip CRC acceleration, and cold-temperature operation down to –40°C.

Technical Context

The MCF51AC256ACPUER implements the ColdFire V1 core with background debug module (BDM), executing ISA_C instructions at up to 50.33 MHz. Its system integration module (SIM) manages reset sources, clock gating, and interrupt routing across 40 peripheral I/O requests handled by the CF1_INTC controller.

It features dual flexible timer modules (FTM1/FTM2) supporting edge-aligned and center-aligned PWM, input capture, deadtime insertion for complementary outputs, and hardware-triggered ADC conversions. The MSCAN module provides full CAN 2.0A/B protocol handling with five receive buffers, three prioritized transmit buffers, and programmable wakeup filtering.

Key Specifications

Pinout & Package

Package: 80-pin LQFP, 14 mm × 14 mm, 0.5 mm pitch, exposed pad (thermal pad not electrically connected).

Key Features

Applications

Equivalent & Alternatives

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

Compared with S9KEAZ128AMLH and MPC5604B, the MCF51AC256ACPUER delivers optimal balance of CAN integration, mixed-signal peripherals, and compact 80-pin LQFP packaging - making it ideal for cost-constrained, space-limited automotive and industrial controllers where ColdFire toolchain familiarity exists.

Availability

MCF51AC256ACPUER is available at Aetrix Electronics and suitable for automotive body electronics, industrial motor drives, medical infusion pumps, and smart energy metering applications requiring stable component supply, long-term lifecycle assurance, and industrial temperature grade support.

Supply support for MCF51AC256ACPUER 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 focused on secure connectivity solutions for automotive, industrial, and IoT markets.

The MCF51AC256ACPUER belongs to NXP's ColdFire microcontroller family, designed specifically for migration from legacy 8-bit MCUs (e.g., MC9S08AC128) to 32-bit architectures while preserving code compatibility and toolchain investment.

FAQ

What is the maximum operating frequency of the MCF51AC256ACPUER?

The MCF51AC256ACPUER operates at up to 50.33 MHz across its full voltage range (2.7–5.5 V) and temperature range (–40°C to +105°C). This frequency is achieved using the multipurpose clock generator (MCG) with PLL/FLL configuration and is validated per electrical characteristics in Table 16 of the Rev.7 datasheet. Performance remains stable under worst-case process, voltage, and temperature corners.

Does the MCF51AC256ACPUER support CAN FD or only classical CAN?

The MCF51AC256ACPUER supports only classical CAN per ISO 11898-1:2003 (CAN 2.0A/B), with data frames up to 8 bytes and bit rates up to 1 Mbps. It does not implement CAN FD features such as variable bit rate, extended data length, or CRC enhancements. The MSCAN module is fully backward-compatible with legacy CAN networks but lacks FD-specific registers or frame handling logic.

How many analog comparator channels does the MCF51AC256ACPUER include?

The MCF51AC256ACPUER includes two independent analog comparators: ACMP1 and ACMP2. Both support rail-to-rail input operation, selectable interrupt on rising/falling/both edges, comparison against internal bandgap reference, and output visibility on dedicated pins (ACMP1O/ACMP2O). This is confirmed in Table 2 (Functional Units) and Section 1.3.1 of the Rev.7 datasheet.

Is the MCF51AC256ACPUER pin-compatible with other members of the MCF51AC256 series?

Yes - the MCF51AC256ACPUER (80-pin LQFP) shares identical pinout and package dimensions with MCF51AC256AVLKE and MCF51AC256ACLKE. All three use the same 80-pin LQFP mechanical outline (Figure 2, page 12), and pin assignments match per Table 4. Differences are limited to CAN presence (A vs. B variants) and temperature grade (V = –40°C to 105°C, C = –40°C to 85°C), not pin function or layout.

What debug interface does the MCF51AC256ACPUER use, and what tools support it?

The MCF51AC256ACPUER uses a single-wire background debug module (BDM) accessible via the BKGD/MS pin. It is supported by P&E Micro's USB-ML-CF and Cyclone FX programmers, as well as CodeWarrior Development Studio v10.x. Real-time trace is enabled through the debug visibility bus (VBUS), allowing non-intrusive program flow analysis without halting execution - a capability documented in Section 1.3.1 and Figure 1 of the Rev.7 datasheet.