NXP Semiconductors MC908GR8CBE

Overview

MC908GR8CBE from Freescale Semiconductor (now NXP) is an 8-bit HCS08 microcontroller featuring 8 KB on-chip flash memory, 512 bytes RAM, and integrated peripherals including 8-channel 10-bit ADC, SCI, SPI, TIM, KBI, and COP watchdog. It operates at up to 8 MHz bus frequency with 3.0–5.5 V supply and targets low-cost embedded control in industrial sensors and appliance motor interfaces.

For engineers reviewing the MC908GR8CBE datasheet, MC908GR8CBE pinout, MC908GR8CBE application, or MC908GR8CBE equivalent, this page delivers verified technical context, package-specific pin functions, real-world use scenarios, and validated alternative options for legacy design continuity and BOM rationalization.

Technical Context

The MC908GR8CBE implements the HCS08 CPU core with enhanced BDM debug support and executes instructions at 1–8 MHz bus clock derived from internal oscillator or external crystal. Its System Integration Module (SIM) manages reset, interrupts, and clock distribution across integrated peripherals.

It integrates a 10-bit successive-approximation ADC with programmable sample time and conversion trigger sources (software, TIM, SCI), plus dual timer modules (TIM1/TIM2) supporting input capture, output compare, and PWM generation with independent prescalers and modulo registers.

Key Specifications

Pinout & Package

MC908GR8CBE is housed in a 28-pin SOIC (Case #751F) package with 600 mil body width, 1.27 mm pitch, and standard JEDEC MS-012AC footprint. Pin assignments are validated per Section 1.5 (Pin Assignments) and Section 1.6 (Pin Functions) of Rev. 4.0 Technical Data.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit microcontroller applications.

Compared with MC908GR8CBE, MC9S08GB60A offers scalable memory and USB while retaining HCS08 instruction compatibility, whereas S9KEAZ128AMLH delivers architectural modernization at the cost of full hardware and software requalification.

Availability

MC908GR8CBE is available at Aetrix Electronics and suitable for industrial sensor nodes, home appliance motor controllers, smart power outlets, and legacy PLC I/O modules requiring stable component supply and long-term obsolescence management.

Supply support for MC908GR8CBE 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 (acquired by NXP in 2015) was a pioneer in 8-bit microcontrollers, emphasizing robustness, low-power operation, and integrated analog peripherals for cost-sensitive embedded systems.

The MC908GR8CBE belongs to the HCS08 family designed specifically for industrial and consumer appliance control where deterministic real-time response, on-chip debug, and mixed-signal integration reduce system BOM count and layout complexity.

FAQ

What is the maximum operating frequency of the MC908GR8CBE?

The MC908GR8CBE supports a maximum bus frequency of 8 MHz, achieved using its internal clock generator module with external crystal (1–8 MHz) or internal oscillator. This frequency determines instruction execution speed and peripheral timing - for example, SCI baud rates and ADC conversion times scale directly with bus clock. The MC908GR8CBE maintains full functionality across its specified 3.0–5.5 V supply range at this speed.

Does the MC908GR8CBE support in-system programming via its BDM interface?

Yes, the MC908GR8CBE supports full in-system programming and debugging via its Background Debug Mode (BDM) single-wire interface. This allows flash memory erasure, programming, and verification without removing the device from the target board. The BDM interface also provides real-time register inspection and breakpoint execution - essential for validating timing-critical functions like motor commutation in the MC908GR8CBE.

What ADC features does the MC908GR8CBE include?

The MC908GR8CBE integrates an 8-channel, 10-bit successive-approximation ADC with programmable sample time, conversion trigger sources (software, TIM overflow, SCI receive), and configurable reference voltage (VDD or external). It supports up to 250 kSPS conversion rate and includes dedicated result registers with left/right justification options - enabling precise analog sensing for applications such as temperature monitoring or current measurement in the MC908GR8CBE.

How does the COP watchdog function in the MC908GR8CBE?

The Computer Operating Properly (COP) module in the MC908GR8CBE provides a configurable windowed watchdog timer with timeout options from 0.5 ms to 1.6 s. It requires periodic service via the COPCTL register to prevent reset; failure to service within the window triggers a hardware reset. This protects against infinite loops or stalled states in safety-relevant firmware running on the MC908GR8CBE.

Is the MC908GR8CBE pin-compatible with other HCS08 family members?

No, the MC908GR8CBE is not universally pin-compatible across the HCS08 family. While it shares the 28-pin SOIC (751F) package with variants like MC908GR4, pin functions differ significantly - for example, Port A signals and peripheral mappings vary between GR4 and GR8. Migration requires validation of I/O assignments, clock configuration, and peripheral initialization sequences specific to the MC908GR8CBE.