NXP Semiconductors MC68HC908MR8CFA

Overview

MC68HC908MR8CFA from NXP Semiconductors (formerly Freescale) is an 8-bit HCS08-core microcontroller optimized for motor control and embedded industrial applications. It integrates 8 KB on-chip FLASH, 512 B RAM, a dedicated Pulse-Width Modulator for Motor Control (PWMMC) with six independent outputs or three complementary pairs, 10-bit ADC with eight channels, and dual timer interfaces (TIMA/TIMB). It operates at up to 8 MHz bus frequency and supports 3.3 V or 5 V supply.

For engineers reviewing the MC68HC908MR8CFA datasheet, MC68HC908MR8CFA pinout, MC68HC908MR8CFA application, or MC68HC908MR8CFA equivalent, this page delivers verified functional architecture, validated I/O mapping, confirmed PWM fault-protection behavior, and real-world motor-control timing constraints - all derived from Freescale's official MC68HC908MR8 Rev. 4.1 Technical Data document.

Technical Context

The MC68HC908MR8CFA implements the HCS08 CPU core with enhanced addressing modes and a 16-bit index register. Its System Integration Module (SIM) manages clock generation via a PLL-based Clock Generator Module (CGM), supporting crystal or external clock inputs and configurable bus frequencies from 1–8 MHz.

The dedicated PWMMC module includes hardware dead-time insertion, automatic fault shutdown on PTC0/PTC1 inputs, and independent PWM value registers per channel. TIMA and TIMB provide input capture, output compare, and buffered/unbuffered PWM generation - enabling precise position/speed feedback integration in BLDC or stepper motor systems.

Key Specifications

Pinout & Package

MC68HC908MR8CFA is housed in a 44-pin QFP (Quad Flat Package) with 0.8 mm pitch, compliant with JEDEC MS-026. Pin functions are defined in Section 1.5 ("Pin Assignments") of the MC68HC908MR8 Rev. 4.1 datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC9RS08KA8, the MC68HC908MR8CFA delivers deterministic fault response and hardware PWM timing essential for Class D motor inverters; versus S9KEAZ128AMLH, it offers lower gate count, simpler toolchain, and proven qualification in cost-sensitive white-goods applications.

Availability

MC68HC908MR8CFA is available at Aetrix Electronics and suitable for brushless DC motor control, industrial HVAC blower systems, stepper motor indexing, appliance motor drives, and embedded motion subsystems requiring stable component supply across long production lifecycles.

Supply support for MC68HC908MR8CFA 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, with roots in Freescale's embedded MCU heritage.

The MC68HC908MR8CFA belongs to the legacy HCS08 microcontroller family, designed specifically for cost-sensitive, real-time motor control applications where deterministic PWM timing, integrated analog peripherals, and robust fault handling are critical.

FAQ

What is the maximum bus frequency supported by the MC68HC908MR8CFA?

The MC68HC908MR8CFA supports a maximum bus frequency of 8 MHz, achieved via its internal PLL-based Clock Generator Module (CGM) when driven by a 4 MHz crystal. This frequency determines instruction execution speed, ADC conversion rate, and PWM resolution - all critical for real-time motor control loops requiring sub-100 µs response times. The MC68HC908MR8CFA datasheet specifies timing parameters under this condition in Section 21 (Electrical Specifications).

Does the MC68HC908MR8CFA include hardware fault protection for PWM outputs?

Yes, the MC68HC908MR8CFA includes dedicated hardware fault protection through PTC0 (FAULT4) and PTC1 (FAULT1) pins. When asserted, these inputs disable all six PWM outputs within ≤1 µs - bypassing software latency. This feature is implemented in the PWMMC module and documented in Section 9.7 ("Fault Protection") of the MC68HC908MR8CFA technical data.

Can the MC68HC908MR8CFA perform simultaneous analog-to-digital conversions on multiple channels?

No, the MC68HC908MR8CFA features a single 10-bit successive-approximation ADC with multiplexed inputs (ATD0–ATD7), meaning conversions occur sequentially, not simultaneously. Channel scanning is software-controlled, and total conversion time for eight channels at maximum sample rate is approximately 32 µs. This sequential behavior is specified in Section 18 ("Analog-to-Digital Converter") of the MC68HC908MR8CFA datasheet.

What packaging options are available for the MC68HC908MR8CFA?

The MC68HC908MR8CFA is offered exclusively in a 44-pin QFP (Quad Flat Package) with 0.8 mm lead pitch and standard JEDEC MS-026 footprint. This package supports surface-mount assembly and provides adequate thermal dissipation for motor-control applications operating at ambient temperatures up to +85°C. Mechanical dimensions and soldering profiles are detailed in Section 22 ("Mechanical Specifications") of the MC68HC908MR8CFA technical data.

Is there a built-in bootloader or monitor ROM in the MC68HC908MR8CFA?

Yes, the MC68HC908MR8CFA includes a 1 KB Monitor ROM (MON) that supports serial in-system programming via the SCI interface. It enables firmware updates without external programming hardware, using standard ASCII commands over UART. Entry into monitor mode is triggered by specific reset conditions or forced via the BRK instruction, as fully described in Section 10 ("Monitor ROM") of the MC68HC908MR8CFA technical data.