NXP Semiconductors MC908MR8CDWE

Overview

MC908MR8CDWE from Freescale Semiconductor is an 8-bit HCS08-core microcontroller with 8 KB on-chip FLASH, 512 B RAM, integrated 10-bit ADC (8 channels), dual 16-bit timers (TIMA/TIMB), SCI serial interface, and a dedicated 6-channel PWM motor control module (PWMMC) supporting complementary outputs with dead-time insertion and fault protection. It operates at up to 8 MHz bus frequency and targets embedded motor control in industrial actuators and small appliances.

For engineers reviewing the MC908MR8CDWE datasheet, MC908MR8CDWE pinout, MC908MR8CDWE application, or MC908MR8CDWE equivalent, key selection criteria include its integrated PWMMC with hardware fault shutdown, 10-bit ADC resolution for analog sensing, SCI for host communication, COP watchdog, and support for low-power Wait/Stop modes in resource-constrained systems.

Technical Context

The MC908MR8CDWE implements the HCS08 CPU core with enhanced addressing modes and a 16-level hardware stack. Its System Integration Module (SIM) manages clock generation, reset sources (POR, LVI, COP, illegal opcode), and exception handling-including IRQ and BRK interrupts-while supporting both Wait and Stop low-power states with configurable wake-up sources.

The Clock Generator Module (CGM) integrates a crystal oscillator and PLL for flexible bus clock derivation, enabling stable operation across voltage and temperature. The Pulse-Width Modulator for Motor Control (PWMMC) provides six independent or three complementary PWM outputs with programmable dead time, automatic fault response via PTC0/PTC1 fault pins, and synchronized initialization with TIMA/TIMB for precise timing-critical motor commutation.

Key Specifications

Pinout & Package

MC908MR8CDWE is housed in a 44-pin QFP (Quad Flat Package) with 0.8 mm pitch, compliant with JEDEC MS-026. The package supports surface-mount reflow assembly and provides thermal and mechanical stability for industrial motor drive environments.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC9RS08KA8CDWE, the MC908MR8CDWE delivers dedicated motor control hardware with faster fault response and complementary PWM, while S9KEAZ128AMLH offers ARM-class scalability at the cost of increased design complexity and power consumption.

Availability

MC908MR8CDWE is available at Aetrix Electronics and suitable for industrial motor drives, appliance control systems, and power tool electronics requiring stable component supply and long-term manufacturing continuity.

Supply support for MC908MR8CDWE 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 robust analog and mixed-signal integration.

The MC908MR8CDWE belongs to the HCS08 family, designed specifically for cost-sensitive, real-time motor control applications where integrated PWM, ADC, and fault handling reduce system-level complexity and improve reliability.

FAQ

What is the maximum bus frequency supported by the MC908MR8CDWE?

The MC908MR8CDWE supports a maximum bus frequency of 8 MHz, derived from its internal Clock Generator Module (CGM) using either a crystal oscillator or PLL-multiplied clock source. This frequency enables deterministic execution of motor control algorithms with sub-microsecond timing resolution for PWM and ADC sampling-critical for maintaining stability in high-speed BLDC commutation sequences. The CGM allows dynamic clock scaling to balance performance and power consumption.

Does the MC908MR8CDWE include hardware fault protection for motor drivers?

Yes, the MC908MR8CDWE includes dedicated hardware fault protection via PTC0 and PTC1 pins feeding directly into the PWMMC module. When asserted, these inputs disable all six PWM outputs within one bus cycle-bypassing software latency-to prevent shoot-through in half-bridge or full-bridge motor driver stages. Fault status is latched and readable via the Fault Status Register, and acknowledgment requires explicit software action through the Fault Acknowledge Register.

Can the MC908MR8CDWE operate in low-power modes while maintaining motor control functionality?

Yes, the MC908MR8CDWE supports Wait and Stop low-power modes while preserving critical motor control functions. In Wait mode, the CPU halts but peripherals-including PWMMC, TIMA/TIMB, and SCI-remain active, allowing continuous PWM output and background communication. In Stop mode, most clocks stop except those needed for wake-up sources (e.g., IRQ, SCI idle detect), enabling ultra-low quiescent current (<1 µA) while retaining state for rapid resumption of motor operation.

What development tools are officially supported for the MC908MR8CDWE?

Freescale's official development ecosystem for the MC908MR8CDWE includes CodeWarrior Development Studio for HCS08 (v5.1+), P&E Micro's Multilink USB debugger, and the DEMO908MR8 evaluation board. These tools provide full flash programming, real-time debugging, and hardware validation of PWMMC timing, ADC sampling, and fault response-ensuring reliable bring-up of motor control firmware without requiring custom JTAG adapters or third-party toolchain adaptation.

Is the MC908MR8CDWE pin-compatible with other members of the HCS08 MR-family?

Yes, the MC908MR8CDWE shares identical pinout and package (44-pin QFP) with MC908MR16CDWE and MC908MR32CDWE, differing only in FLASH size (8 KB vs. 16 KB vs. 32 KB) and RAM capacity. This enables hardware reuse across product variants-designers can prototype with MC908MR8CDWE and scale firmware features upward without PCB redesign, provided layout accommodates the same thermal and decoupling requirements across the MR-family.