NXP Semiconductors MC68331CFC16B1

Overview

MC68331CFC16B1 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 a 132-pin PQFP package, supports external bus interfacing up to 24-bit address/16-bit data, and delivers low-power operation via LPSTOP command and 32.768-kHz crystal-based clock synthesis - used in industrial motor control and embedded automation systems.

For engineers reviewing the MC68331CFC16B1 datasheet, MC68331CFC16B1 pinout, MC68331CFC16B1 application, or MC68331CFC16B1 equivalent, key selection criteria include its static CPU32 architecture, integrated watchdog/timer/peripheral modules, 132-pin QFP thermal profile, and compatibility with legacy 68K-based real-time control firmware stacks.

Technical Context

The MC68331CFC16B1 implements a modular intermodule bus (IMB) architecture with standardized 24-bit address and 16-bit data lines, enabling deterministic communication between CPU32, SIM, GPT, and QSM. Its SIM provides programmable chip-selects (CS0–CS10), periodic interrupt generation, and system protection logic including bus monitor, HALT monitor, and software watchdog timer.

GPT includes two 16-bit free-running counters, three input capture channels, four output compare channels, and dual PWM outputs; QSM integrates both SCI (UART) and QSPI subsystems with 80-byte RAM and automatic transfer queuing - all accessible via shared PQS[7:0] I/O pins under port multiplexing.

Key Specifications

Pinout & Package

MC68331CFC16B1 uses a 132-pin PQFP package with 0.65 mm lead pitch and exposed thermal pad (non-electrical). Pin assignments follow Figure 2 of MC68331TS/D Rev. 2, with dedicated signal groups for address/data bus, peripheral I/O (PQS[7:0], PGP[7:0], PF[7:0], PE[7:0], PC[6:0]), and system control (RESET, HALT, BERR, CLKOUT, EXTAL/XTAL).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC68332CAG16 and MC68376CAG16, the MC68331CFC16B1 delivers optimal cost-performance balance for pure serial+PWM+capture applications without CAN or dual-SCI overhead - retaining full 68K software compatibility and industrial temperature rating.

Availability

MC68331CFC16B1 is available at Aetrix Electronics and suitable for industrial motor control, PLC I/O modules, legacy equipment retrofits, automated test equipment, and embedded automation systems requiring stable component supply across extended product lifecycles.

Supply support for MC68331CFC16B1 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 for deterministic real-time control applications requiring high integration, low power, and long-term availability - targeting industrial automation, motion control, and legacy system modernization.

FAQ

What is the maximum guaranteed operating frequency of the MC68331CFC16B1?

The MC68331CFC16B1 is rated for a maximum system clock frequency of 16 MHz, as confirmed by Freescale's MC68331TS/D Rev. 2 datasheet Table 1. This rating applies across the full –40°C to +85°C industrial temperature range and assumes proper decoupling and clock signal integrity. Operation above 16 MHz is not characterized or guaranteed.

Does the MC68331CFC16B1 support CAN bus communication?

No, the MC68331CFC16B1 does not include a CAN controller. Its serial capabilities are limited to the Queued Serial Module (QSM), which implements SCI (UART) and QSPI interfaces only. For CAN-enabled variants, Freescale introduced the MC68376 series - the MC68331CFC16B1 lacks both CAN hardware and associated registers.

What power supply domains does the MC68331CFC16B1 require?

The MC68331CFC16B1 requires three distinct power domains: VDDSYN for the clock synthesizer, VSSI/VDDI for internal logic (CPU32, SIM, GPT, QSM), and VSSE/VDDE for external bus drivers and I/O buffers. Each domain must be independently decoupled; mixing domains risks timing violations or latch-up per Section 2.2 of MC68331TS/D.

Is the MC68331CFC16B1 pin-compatible with other MC68331 variants in 132-pin PQFP?

Yes, the MC68331CFC16B1 shares identical pinout and package dimensions with MC68331CFC16 (no suffix) and MC68331VFC16, as verified in Table 1 of MC68331TS/D Rev. 2. Differences are limited to temperature grade (–40°C to +85°C) and screening - electrical characteristics and pin functions remain fully aligned.

How does the MC68331CFC16B1 handle external bus arbitration?

The MC68331CFC16B1 implements full external bus arbitration using BR (Bus Request), BG (Bus Grant), and BGACK (Bus Grant Acknowledge) signals. When BR is asserted by an external master, the MCU releases AS, R/W, and address/data lines after completing the current cycle and asserts BG; BGACK confirms handoff. This allows coexistence with DMA controllers or secondary processors on the same bus.