NXP Semiconductors MC908GR4CDWE

Overview

MC908GR4CDWE from Freescale Semiconductor is an 8-bit HCS08 microcontroller featuring 4 KB on-chip flash memory, 192 B RAM, and a 2.1–5.5 V operating voltage range. It integrates an 8-channel 8-bit ADC, SCI and SPI serial interfaces, two 16-bit timer modules (TIM1/TIM2), and low-power wait/stop modes. It targets cost-sensitive embedded control applications such as appliance motor control and industrial sensor nodes.

For engineers reviewing the MC908GR4CDWE datasheet, MC908GR4CDWE pinout, MC908GR4CDWE application, or MC908GR4CDWE equivalent, key selection criteria include its 28-pin SOIC package, 8 MHz internal bus speed, flash endurance (10k erase/write cycles), COP watchdog, and LVI reset threshold - all critical for reliable operation in temperature-variable consumer and industrial environments.

Technical Context

The MC908GR4CDWE implements the HCS08 CPU core with enhanced addressing modes and a 16-bit index register, supporting up to 16 MB linear address space via expanded memory mapping. Its System Integration Module (SIM) provides clock generation, reset control, and interrupt vector management with configurable prescalers and oscillator start-up timing.

Peripheral integration includes a 16-bit Timer Interface Module (TIM) with input capture, output compare, and PWM capability; a Serial Communications Interface (SCI) compliant with RS-232 electrical levels using external drivers; and a Serial Peripheral Interface (SPI) supporting master/slave operation at up to 2 MHz SCK frequency with programmable polarity and phase.

Key Specifications

Pinout & Package

MC908GR4CDWE is housed in a 28-pin Small Outline Integrated Circuit (SOIC) package (Case #751F), 300 mil body width, with 0.025 inch lead pitch and gull-wing leads. Thermal resistance θ_JA = 110 °C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC908GR4CDWE, the GR8 variant offers double flash capacity with full compatibility, while the RS08KA2 sacrifices memory and interface flexibility for cost and size reduction - making the GR4 optimal for balanced performance, integration, and BOM cost in mid-complexity embedded systems.

Availability

MC908GR4CDWE is available at Aetrix Electronics and suitable for appliance motor control, industrial sensor nodes, smart power outlets, and medical diagnostic handhelds requiring stable component supply across long production lifecycles.

Supply support for MC908GR4CDWE 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) was a leading designer of embedded processors and analog/mixed-signal ICs, emphasizing automotive, industrial, and consumer microcontrollers.

The MC908GR4CDWE belongs to the HCS08 family - engineered for cost-effective, low-power 8-bit control in resource-constrained applications where flash programmability, integrated peripherals, and robust reset/watchdog features are essential.

FAQ

What is the maximum system bus frequency supported by the MC908GR4CDWE?

The MC908GR4CDWE supports a maximum bus frequency of 8 MHz. This is derived from its internal clock generator module, which can divide the external crystal or internal oscillator output to achieve stable operation within the specified voltage and temperature ranges. The MC908GR4CDWE's timing specifications assume this 8 MHz bus clock for all peripheral modules including TIM, SCI, and SPI.

Does the MC908GR4CDWE include hardware debug support?

Yes, the MC908GR4CDWE incorporates a factory-programmed 256-byte Monitor ROM (MON) that enables in-circuit debugging and flash programming via the SCI interface without requiring external debug hardware. This MON supports commands like READ, WRITE, and RUN, allowing firmware updates and verification directly through a UART connection - a key capability for field maintenance of the MC908GR4CDWE.

What are the low-power modes available on the MC908GR4CDWE and how do they differ?

The MC908GR4CDWE supports Wait and Stop low-power modes. In Wait mode, the CPU halts but peripherals remain clocked, allowing wake-up via IRQ, KBI, or SCI interrupts. In Stop mode, nearly all clocks are disabled, reducing current draw to under 1 µA; wake-up occurs only via RESET, IRQ, or KBI. Both modes preserve RAM contents and register states, ensuring deterministic resumption after wake-up - a critical behavior for battery-powered implementations of the MC908GR4CDWE.

Can the MC908GR4CDWE operate from a 3.3 V supply?

Yes, the MC908GR4CDWE operates across a 2.1 V to 5.5 V supply range, fully supporting 3.3 V nominal systems. At 3.3 V, it delivers guaranteed 8 MHz bus performance per its electrical specifications, and all I/O pins are 5 V tolerant when configured as inputs - simplifying interface with mixed-voltage peripherals in designs using the MC908GR4CDWE.

How many channels does the ADC in the MC908GR4CDWE support and what is its resolution?

The MC908GR4CDWE integrates an 8-channel, 8-bit successive-approximation analog-to-digital converter (ADC). Each channel supports single-ended input with software-selectable reference (VDD or internal bandgap), and conversion time is fixed at 25 µs per sample. This ADC is optimized for direct interfacing with sensors like thermistors, potentiometers, and current shunts in applications relying on the MC908GR4CDWE for real-time analog monitoring.