NXP Semiconductors MC68908GR16MFJE

Overview

MC68908GR16MFJE from Freescale Semiconductor is an 8-bit HCS08 microcontroller with 16 KB on-chip Flash, 512 B RAM, integrated 10-bit ADC (8-channel), SPI, ESCI, and TIM modules. It operates at up to 8 MHz bus frequency, supports low-power Wait/Stop modes, and targets embedded control in industrial sensors and automotive body electronics.

For engineers reviewing the MC68908GR16MFJE datasheet, MC68908GR16MFJE pinout, MC68908GR16MFJE application, or MC68908GR16MFJE equivalent, key selection criteria include Flash endurance (100k erase/write cycles), ADC sampling rate (≤200 kSPS), CGM PLL lock time (<5 ms), COP watchdog timeout range (1.7–272 ms), and 40-pin QFP package compatibility with legacy M68HC08 designs.

Technical Context

The MC68908GR16MFJE implements the CPU08 core with 16-bit index register, 8-bit accumulator, and 16-level hardware stack. Its Clock Generator Module (CGM) integrates a crystal oscillator, PLL with programmable multiplier (×1 to ×32), and base clock selector supporting multiple internal/external sources including CGMXCLK and BUS CLOCK.

Peripheral integration includes an Enhanced Serial Communications Interface (ESCI) with LIN-compatible baud rate generation, a 16-bit Timer Interface Module (TIM) with two input-capture/output-compare channels, and a System Integration Module (SIM) managing reset, interrupt vectors, and configuration registers including CONFIG and COPCTL.

Key Specifications

Pinout & Package

MC68908GR16MFJE is housed in a 40-pin Quad Flat Package (QFP) with 0.8 mm lead pitch, compliant with JEDEC MS-026. Pin assignments are defined per Chapter 1.4 and 1.5 of Rev. 5.0 datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC9RS08KA8CFD, MC68908GR16MFJE provides PLL-based clock flexibility and mature HCS08 ecosystem support; versus S9KEAZ128AMLH, it offers lower BOM cost and simpler firmware development for established 8-bit control architectures.

Availability

MC68908GR16MFJE is available at Aetrix Electronics and suitable for industrial sensor nodes, automotive body electronics, and smart appliance control requiring stable component supply across extended product lifecycles.

Supply support for MC68908GR16MFJE 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, analog, and connectivity solutions for automotive, industrial, and consumer markets.

The MC68HC908 family was designed for cost-sensitive, low-power 8-bit control applications where Flash programmability, peripheral integration, and long-term supply stability are essential.

FAQ

What is the maximum bus frequency supported by the MC68908GR16MFJE?

The MC68908GR16MFJE supports a maximum bus frequency of 8 MHz, derived from its Clock Generator Module's PLL output (CGMXCLK). This frequency is achieved using the internal PLL with appropriate multiplier and divider settings, and is validated across the full operating voltage range (2.7–5.5 V) and temperature range (–40°C to +85°C) per Section 20.1 of the Rev. 5.0 datasheet.

Does the MC68908GR16MFJE include a hardware watchdog timer?

Yes, the MC68908GR16MFJE includes a Computer Operating Properly (COP) module that functions as a configurable hardware watchdog timer. The COP timeout is programmable from 1.7 ms to 272 ms via the COPCTL register, and it resets the device if not serviced before timeout. The COP is disabled during STOP mode and can be disabled permanently via the COPD bit in CONFIG register.

Can the MC68908GR16MFJE operate from a 3.3 V supply?

Yes, the MC68908GR16MFJE is fully specified to operate from a 3.3 V supply, as confirmed in Section 20.6 ("3.3-Vdc Electrical Characteristics") of the Rev. 5.0 datasheet. All I/O pins are 5 V tolerant when configured as inputs, and the ADC reference can be set to VDDAD (3.3 V) for ratiometric measurements.

How many analog input channels does the ADC in the MC68908GR16MFJE support?

The MC68908GR16MFJE integrates a 10-bit successive-approximation ADC with 8 analog input channels (AD0–AD7), mapped to Port B pins PTB0–PTB7. Channel selection is controlled via the ADCSC1 register, and conversions can be triggered manually, by timer overflow, or by ESCI receive events per Section 3.3.4.

Is the MC68908GR16MFJE pin-compatible with other members of the MC68HC908 family?

No, the MC68908GR16MFJE is not universally pin-compatible across the MC68HC908 family. While it shares the 40-pin QFP package with variants like MC68HC908GR8, differences in peripheral mapping (e.g., TIM2 channel assignment to PTD7 vs. PTD6) and register layout require verification against individual datasheets. Pin compatibility must be confirmed per specific variant - e.g., MC68HC908GR16MFJE matches MC68HC908GR16MFA in pinout but differs from GR8 derivatives.