NXP Semiconductors MC68331CAG16

Overview

MC68331CAG16 from Freescale Semiconductor is a 32-bit modular microcontroller featuring the CPU32 core, System Integration Module (SIM), General-Purpose Timer (GPT), and Queued Serial Module (QSM). It operates at 16 MHz with fully static design, supports 32.768-kHz crystal-based low-power clock synthesis, and delivers 16-bit data/24-bit address bus capability for embedded control applications in industrial automation and motor control systems.

For engineers reviewing the MC68331CAG16 datasheet, MC68331CAG16 pinout, MC68331CAG16 application, or MC68331CAG16 equivalent, key selection criteria include its integrated watchdog timer, programmable chip-select logic, dual-function QSPI/SCI serial interface, and hardware breakpoint support for background debugging mode - all critical for deterministic real-time control firmware development.

Technical Context

The MC68331CAG16 implements a modular architecture where CPU32, SIM, GPT, and QSM communicate via a standardized 24-bit address/16-bit data intermodule bus (IMB). Its system clock supports both external reference (32.768 kHz) and direct external clock input, with maximum operation at 16 MHz and full static timing - enabling zero-clock-stop retention of register and memory state.

Peripheral integration includes three interrupt priority levels (IRQ7–IRQ1), 11 programmable chip-select outputs with base/option registers, and dual-mode serial I/O: QSPI with 80-byte RAM and automatic transfer queue, plus SCI with modulus baud rate generation and parity support - all accessible through shared PQS port pins.

Key Specifications

Pinout & Package

MC68331CAG16 is housed in a 132-pin Plastic Quad Flat Package (PQFP) with 0.65 mm lead pitch, rated for –40°C to +85°C operating temperature. Pin assignments follow Freescale's standard 132-pin QFP layout (Figure 2, MC68331TS/D Rev. 2).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC68332CAG16, the MC68331CAG16 offers proven reliability in long-lifecycle industrial deployments but lacks extended chip-select flexibility; versus MC9328MX1CZK, it provides deterministic real-time behavior and minimal BOM cost, though without modern connectivity or processing throughput.

Availability

MC68331CAG16 is available at Aetrix Electronics and suitable for industrial PLC I/O modules, motor drive controllers, energy meter communication hubs, and factory automation HMI controllers requiring stable component supply across extended product lifecycles.

Supply support for MC68331CAG16 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) is a fabless semiconductor company specializing in embedded processing, analog, and connectivity solutions for automotive, industrial, and networking markets.

The MC68331 product line was designed as a high-integration, cost-optimized 32-bit microcontroller family for deterministic real-time control applications - emphasizing modularity, low-power operation, and debuggability in resource-constrained environments.

FAQ

What is the operating temperature range for the MC68331CAG16?

The MC68331CAG16 is specified for industrial operation from –40°C to +85°C. This rating is confirmed by Freescale's ordering information table, where "C" in the part number denotes the commercial/industrial temperature grade, distinct from "V" (–40°C to +105°C) and "M" (–40°C to +125°C) variants. The device maintains full functionality across this range without derating.

Does the MC68331CAG16 support external memory expansion?

Yes, the MC68331CAG16 supports external memory expansion via its 24-bit address bus (ADDR[23:0]) and 16-bit data bus (DATA[15:0]), coupled with 11 programmable chip-select outputs (CS[10:0]) and dedicated control signals including AS, R/W, and BERR. These features enable direct interfacing with SRAM, EPROM, and peripheral ASICs without external glue logic.

How does the MC68331CAG16 implement low-power operation?

The MC68331CAG16 implements low-power operation through its fully static CMOS design and the CPU32's LPSTOP instruction, which gates the system clock while preserving register and memory contents. Power consumption is further minimized by disabling unused peripheral clocks via SIM configuration registers, and by using the 32.768-kHz crystal oscillator for low-frequency timing during sleep states.

What debug interfaces are available on the MC68331CAG16?

The MC68331CAG16 provides Background Debug Mode (BDM) via dedicated pins: BKPT (hardware breakpoint), DSI (serial data in), DSO (serial data out), and DSCLK (serial clock). This interface enables non-intrusive firmware inspection, real-time register access, and code stepping without requiring JTAG - a key differentiator for legacy industrial toolchains.

Is the MC68331CAG16 pin-compatible with other members of the MC6833x family?

Yes, the MC68331CAG16 shares identical 132-pin PQFP packaging and pinout with MC68331CFC16, MC68331VFC16, and MC68331MFC16 - differing only in temperature grade and tray packaging. However, it is not pin-compatible with 144-pin QFP variants (e.g., MC68331CFV16) due to differing pin counts and assignments.