NXP Semiconductors MC68HC908GP32CFB

Overview

MC68HC908GP32CFB from Motorola is an 8-bit HCS08-core microcontroller with 32 KB on-chip FLASH, 1 KB RAM, and integrated peripherals including 12-bit ADC (8 channels), dual TIM modules, SCI, SPI, KBI, and PLL-based clock generator. It operates at up to 8 MHz bus frequency and supports low-power Wait/Stop modes. Used in industrial control panels requiring deterministic real-time I/O response and field-upgradable firmware.

For engineers reviewing the MC68HC908GP32CFB datasheet, MC68HC908GP32CFB pinout, MC68HC908GP32CFB application, or MC68HC908GP32CFB equivalent, key selection criteria include FLASH endurance (10K erase/write cycles), 44-pin QFP package compatibility, COP watchdog timing tolerance (±25%), and CGM PLL lock time (<10 ms).

Technical Context

The MC68HC908GP32CFB implements the CPU08 core with 16-bit address space, supporting indexed, extended, and relative addressing. Its Clock Generator Module integrates a crystal oscillator, PLL multiplier (×1 to ×32), and base clock selector for flexible system timing.

The device features two independent Timer Interface Modules (TIM1/TIM2) with input capture, output compare, and PWM generation; a 12-bit successive-approximation ADC with programmable sample time and conversion trigger sources; and a Monitor ROM enabling in-system programming via SCI without external debugger.

Key Specifications

Pinout & Package

MC68HC908GP32CFB is housed in a 44-pin Quad Flat Package (QFP), case number 824A, with 0.8 mm lead pitch and 10 mm × 10 mm body size per Motorola Mechanical Specifications Section 24.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC9RS08KA8CFD, MC68HC908GP32CFB delivers higher ADC resolution and dual-timer flexibility at lower cost; versus S9KEAZ128AMLH, it offers proven reliability in temperature-stressed industrial environments with simpler certification paths.

Availability

MC68HC908GP32CFB is available at Aetrix Electronics and suitable for industrial motor control, smart sensor nodes, appliance user interfaces, and automotive body control applications requiring stable component supply and long-term manufacturing continuity.

Supply support for MC68HC908GP32CFB 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

Motorola Semiconductor (now NXP Semiconductors) pioneered embedded microcontrollers for industrial and automotive markets, emphasizing robustness, longevity, and toolchain maturity.

The MC68HC908GP32CFB belongs to the HC08 family, designed for cost-sensitive, real-time control applications demanding reliable FLASH-based firmware, deterministic interrupt latency, and low-voltage operation in harsh environments.

FAQ

What is the maximum operating frequency of the MC68HC908GP32CFB?

The MC68HC908GP32CFB achieves a maximum bus frequency of 8 MHz, derived from its internal PLL which multiplies a 1–8 MHz crystal input. This frequency governs instruction execution speed, peripheral timing, and ADC conversion rate. The PLL lock time is specified at under 10 ms, ensuring rapid startup in systems requiring fast wake-from-Stop transitions. MC68HC908GP32CFB does not support external clock sources beyond the crystal oscillator interface.

Does the MC68HC908GP32CFB support in-system programming without external hardware?

Yes, the MC68HC908GP32CFB includes a 512-byte Monitor ROM (MON) that enables in-system programming of its 32 KB FLASH memory via the SCI serial interface using standard UART commands. This eliminates the need for dedicated programming hardware during field updates. MC68HC908GP32CFB requires only a simple level-shifter circuit for RS-232 communication and executes FLASH erase/write operations autonomously once initiated through MON commands.

How many analog input channels does the ADC in the MC68HC908GP32CFB support?

The MC68HC908GP32CFB integrates a 12-bit successive-approximation ADC with eight analog input channels mapped to PTB0 through PTB7. Each channel supports programmable sample time and conversion triggering via software, timer overflow, or external event. MC68HC908GP32CFB specifies ±1 LSB integral nonlinearity and supports differential reference configuration using VREFH/VREFL pins for improved noise immunity in noisy industrial settings.

What low-power modes are implemented in the MC68HC908GP32CFB?

The MC68HC908GP32CFB implements two hardware-supported low-power modes: Wait mode (CPU halted, peripherals remain clocked and functional) and Stop mode (all clocks gated except optional RTC or LVI, RAM retained, wake via IRQ/KBI/TBM). MC68HC908GP32CFB guarantees RAM retention in Stop mode down to 2.7 V and draws less than 1 µA typical current, making it suitable for battery-backed applications requiring infrequent wake events.

Is the MC68HC908GP32CFB pin-compatible with other members of the HC08 family?

No, the MC68HC908GP32CFB is not pin-compatible with other HC08 devices such as the MC68HC908JB8 or MC68HC908QT4 due to differences in peripheral mapping, I/O count, and package pinout. Its 44-pin QFP (case 824A) assignment is unique to the GP32 variant. MC68HC908GP32CFB shares the same instruction set and memory map architecture but requires dedicated PCB layout; migration to other HC08 parts necessitates board redesign and firmware adaptation.