NXP Semiconductors MC68331CAG25

Overview

MC68331CAG25 from Freescale Semiconductor is a 32-bit modular microcontroller integrating CPU32 core, System Integration Module (SIM), General-Purpose Timer (GPT), and Queued Serial Module (QSM). It operates at up to 25 MHz system clock (confirmed via package suffix 'G25' and Freescale ordering conventions), supports 24-bit addressing and 16-bit data bus, and targets industrial control systems requiring deterministic real-time response with integrated watchdog, periodic interrupt, and external bus interface.

For engineers reviewing the MC68331CAG25 datasheet, MC68331CAG25 pinout, MC68331CAG25 application, or MC68331CAG25 equivalent, this page delivers verified technical context, validated pin functions, confirmed timing parameters, and real-world use cases in motor control, PLC I/O modules, and embedded instrumentation where static operation, low-power stop mode, and dual serial interfaces are critical.

Technical Context

The MC68331CAG25 implements a modular architecture using an Intermodule Bus (IMB) with 24 address and 16 data lines, enabling standardized communication between CPU32, SIM, GPT, and QSM. Its SIM provides programmable chip selects (CS[10:0]), system protection logic including bus monitor and software watchdog, and clock synthesis based on 32.768-kHz crystal reference.

CPU32 executes instructions in fully static mode, supporting loop execution, table lookup/interpolate, and trace-on-change-of-flow debugging. The GPT includes two 16-bit free-running counters, three input capture channels, four output compare channels, and two PWM outputs-enabling precise timing, pulse accumulation, and servo drive control without external peripherals.

Key Specifications

Pinout & Package

MC68331CAG25 uses a 132-pin PQFP package with 0.65 mm pitch, designed for industrial PCB assembly and thermal reliability across –40°C to +85°C ambient.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 32-bit industrial microcontroller applications.

Compared with MC68332CAG25 and MCF52235CAG80, the MC68331CAG25 delivers optimal balance of deterministic real-time control, integrated peripherals, and industrial temperature reliability - especially where QSM queuing, GPT input capture, and static operation are design-critical.

Availability

MC68331CAG25 is available at Aetrix Electronics and suitable for industrial motor control, PLC I/O modules, embedded instrumentation, and automotive body electronics requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MC68331CAG25 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) specialized in high-reliability microcontrollers for industrial, automotive, and aerospace applications, emphasizing robust real-time performance and long-term supply assurance.

The MC68331CAG25 belongs to the 68300 family of modular microcontrollers, designed specifically for deterministic embedded control applications where integrated peripherals, static operation, and field-proven reliability outweigh raw clock speed.

FAQ

What is the maximum operating frequency of the MC68331CAG25?

The MC68331CAG25 is rated for a maximum system clock frequency of 25 MHz, as indicated by the 'G25' suffix in its part number and confirmed by Freescale's timing specifications for the CPU32 core and IMB interface. This frequency applies across the full –40°C to +85°C operating temperature range and supports deterministic execution of real-time control loops without timing violations.

Does the MC68331CAG25 support external memory expansion?

Yes, the MC68331CAG25 supports external memory expansion via its 24-bit address bus (ADDR[23:0]) and 16-bit data bus (DATA[15:0]), coupled with dedicated control signals including AS, R/W, DS, and eleven programmable chip-select outputs (CS[10:0]). This enables direct connection to SRAM, EPROM, or peripheral ASICs with configurable wait-state insertion and bus sizing.

How does the MC68331CAG25 handle low-power operation?

The MC68331CAG25 implements low-power operation through its fully static CPU32 design and dedicated LPSTOP instruction. When executed, LPSTOP halts the system clock while preserving all register and memory contents - enabling immediate wake-up on interrupt without reinitialization. Power consumption is further reduced by disabling unused peripheral clocks via SIM configuration registers.

What serial communication interfaces are integrated into the MC68331CAG25?

The MC68331CAG25 integrates the Queued Serial Module (QSM), which provides two concurrent serial interfaces: an enhanced SCI (UART-compatible) supporting modulus baud rate generation and parity, and a QSPI interface with 80-byte RAM buffer enabling up to 16 automatic transfers. Both share the PQS[7:0] pin group and are software-configurable at runtime.

Is the MC68331CAG25 pin-compatible with other members of the 68300 family?

No, the MC68331CAG25 is not pin-compatible with other 68300-family devices such as the MC68332 or MC68360. While sharing architectural similarities, differences in peripheral integration (e.g., QSM depth, SIM register layout) and pin assignments (e.g., PCS[3:0] vs. dedicated SCI pins) require unique PCB layouts. Migration requires schematic and layout revision, though software can often be reused with minor driver updates.