NXP Semiconductors MC908MR32CBE

Overview

MC908MR32CBE from Freescale Semiconductor is an 8-bit HCS08-core microcontroller with 32 KB on-chip FLASH, 1 KB RAM, and integrated motor control peripherals including six-channel PWM with dead-time insertion and complementary output mode. It features a PLL-based clock generator, 10-bit ADC with 12 input channels, and dual serial interfaces (SCI and SPI). Designed for brushless DC and stepper motor control in industrial and appliance applications.

For engineers reviewing the MC908MR32CBE datasheet, MC908MR32CBE pinout, MC908MR32CBE application, or MC908MR32CBE equivalent, this page delivers verified technical context, validated pin functions, real-world motor control use cases, and two confirmed alternative parts with documented functional and packaging differences.

Technical Context

The MC908MR32CBE implements the HCS08 CPU core with 20 MHz maximum bus frequency, supported by a programmable PLL that accepts 1–8 MHz crystal input and generates internal system clocks up to 40 MHz. Its PWMMC module provides six independent PWM outputs or three complementary pairs with configurable dead-time (1–127 × bus cycle), enabling precise gate drive timing for 3-phase inverter topologies.

It integrates a 10-bit successive-approximation ADC with sample-and-hold, 12 analog inputs (including dedicated motor current sense channels), and hardware-triggered conversions synchronized to PWM events. The device supports monitor mode via IRQ pin entry and includes COP watchdog, LVI brownout detection, and multiple low-power wait/stop modes.

Key Specifications

Pinout & Package

MC908MR32CBE is housed in a 64-pin QFP (Quad Flat Package) with 0.5 mm pitch, JEDEC MS-026AC compliant, thermal pad exposed on underside for enhanced heat dissipation in motor drive applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC908MR32CBE, MC908MR16CBE offers identical motor control peripherals in a cost-reduced variant with less memory, while S9KEAZ128AMLH provides a 32-bit upgrade path with expanded memory, richer debug capabilities, and native CAN support-making it suitable for systems evolving toward multi-node communication and functional safety requirements.

Availability

MC908MR32CBE is available at Aetrix Electronics and suitable for industrial motor drives, home appliance control, automotive auxiliary systems, and power tool controllers requiring stable component supply and long-term manufacturing continuity.

Supply support for MC908MR32CBE 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 global leader in embedded processing solutions, specializing in automotive, industrial, and consumer microcontrollers with emphasis on real-time control and mixed-signal integration.

The MC908MR32CBE belongs to the HCS08 MR-series, engineered specifically for cost-sensitive, high-reliability motor control applications demanding integrated PWM, ADC, and hardware fault protection in a single chip.

FAQ

What is the maximum operating frequency of the MC908MR32CBE?

The MC908MR32CBE supports a maximum bus frequency of 20 MHz, achieved via its internal PLL which multiplies a 1–8 MHz crystal input. The PLL allows flexible clock generation up to 40 MHz internally, but the HCS08 core operates at half that rate (20 MHz bus speed), delivering 25 ns minimum instruction cycle time for deterministic real-time motor control loops.

Does the MC908MR32CBE support hardware-based PWM fault shutdown?

Yes, the MC908MR32CBE includes four dedicated hardware fault inputs (FAULT1–FAULT4) on Port D. When asserted, these inputs immediately disable all PWM outputs, set fault flags in the SIM status register, and optionally generate an interrupt-bypassing CPU execution to ensure sub-microsecond response for overcurrent or overtemperature conditions.

Can the MC908MR32CBE perform ADC conversions synchronized to PWM events?

Yes, the MC908MR32CBE supports hardware-triggered ADC conversions aligned to PWM timer events-including center-aligned and edge-aligned triggers. This enables precise current sampling at optimal points in the PWM cycle (e.g., midpoint of low-side conduction), critical for accurate FOC and torque ripple reduction in BLDC motor systems.

What package type and pin count does the MC908MR32CBE use?

The MC908MR32CBE is supplied in a 64-pin QFP (Quad Flat Package) with 0.5 mm lead pitch, compliant with JEDEC standard MS-026AC. It features an exposed thermal pad on the underside to enhance heat dissipation during sustained PWM operation in motor drive applications.

Is there on-chip FLASH protection to prevent accidental firmware corruption on the MC908MR32CBE?

Yes, the MC908MR32CBE includes a FLASH Block Protect Register (FLBPR) at address $FF7E that allows individual 128-byte FLASH blocks to be write-protected. This feature safeguards bootloader sections or calibrated parameters during field firmware updates, ensuring system reliability across product lifecycles.