NXP Semiconductors MC68HC908AB32CFU

Overview

MC68HC908AB32CFU from NXP (formerly Freescale) is an 8-bit HCS08-core microcontroller with 32 KB on-chip FLASH, 1 KB RAM, and 512 B EEPROM. It integrates dual 16-bit timer modules (TIMA/TIMB), a 10-bit 8-channel ADC, SCI and SPI serial interfaces, and a PLL-based clock generator supporting up to 8 MHz bus frequency. Used in industrial sensor nodes and motor control subsystems requiring deterministic real-time response.

For engineers reviewing the MC68HC908AB32CFU datasheet, MC68HC908AB32CFU pinout, MC68HC908AB32CFU application, or MC68HC908AB32CFU equivalent, key selection criteria include its 48-pin LQFP package, 5 V operation, COP watchdog, low-voltage inhibit (LVI), and Monitor ROM-based in-circuit programming capability.

Technical Context

The MC68HC908AB32CFU implements the HCS08 CPU core with enhanced addressing modes and a 16-level hardware stack. Its System Integration Module (SIM) manages reset sources-including POR, LVI, COP timeout, and illegal opcode-and coordinates low-power Wait/Stop modes with wake-up via IRQ, KBI, or SCI.

The Clock Generator Module (CGM) combines a crystal oscillator and PLL to generate stable internal clocks; it supports automatic PLL lock acquisition and configurable bandwidth for jitter-sensitive timing applications. The ADC operates with programmable sample time and conversion trigger sources including TIMA/TIMB compare events and software commands.

Key Specifications

Pinout & Package

MC68HC908AB32CFU is housed in a 48-pin LQFP package with exposed thermal pad. Pin functions are defined per Section 1.5–1.6 of the Rev. 1.1 datasheet, including dedicated analog supply (VDDA/VSSA), external crystal (OSC1/OSC2), and multi-function I/O ports A–H.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC9RS08KA8CFU, the MC68HC908AB32CFU delivers higher ADC channel count and dual-timer flexibility; versus S9KEAZ128AMLH, it offers proven field reliability and minimal BOM cost in mature 5 V industrial systems where ARM migration is unjustified.

Availability

MC68HC908AB32CFU is available at Aetrix Electronics and suitable for industrial sensor nodes, motor control subsystems, smart power meter interfaces, and legacy PLC I/O modules requiring stable component supply across extended product lifecycles.

Supply support for MC68HC908AB32CFU 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

NXP Semiconductors is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT markets.

The MC68HC908AB32CFU belongs to the legacy HCS08 microcontroller family, designed for cost-sensitive, high-reliability 5 V embedded control applications in harsh industrial environments.

FAQ

What is the maximum operating frequency of the MC68HC908AB32CFU?

The MC68HC908AB32CFU supports a maximum bus frequency of 8 MHz, achieved via its integrated PLL-based Clock Generator Module (CGM). This frequency is derived from an external crystal (1–8 MHz) and is used for all internal peripherals and CPU timing. The HCS08 core executes instructions at this bus rate, delivering deterministic real-time performance suitable for motor control and sensor acquisition loops.

Does the MC68HC908AB32CFU support in-system programming without external hardware?

Yes, the MC68HC908AB32CFU includes a 2 KB Monitor ROM (MON) that enables full in-system programming via its SCI interface. Using standard UART communication, users can erase and reprogram FLASH memory, configure EEPROM, and verify code integrity-all without a JTAG or BDM debugger. This capability is documented in Section 10 of the Rev. 1.1 technical data and is fully functional on the MC68HC908AB32CFU.

How many ADC channels does the MC68HC908AB32CFU provide, and what is their resolution?

The MC68HC908AB32CFU integrates a 10-bit successive-approximation ADC with 8 input channels (ATD0–ATD7), mapped to PTB0–PTB7. It achieves ±1 LSB integral nonlinearity (INL) under specified conditions and supports software, timer, or external trigger initiation. Conversion time is typically 12 µs, making it suitable for sampling rates up to ~83 kSPS in burst mode.

Can the MC68HC908AB32CFU operate reliably in brown-out conditions?

Yes, the MC68HC908AB32CFU includes a dedicated Low-Voltage Inhibit (LVI) circuit that monitors VDD and asserts a hardware reset when voltage falls below 4.25 V. This feature protects FLASH and EEPROM contents from corruption during power transients and ensures safe restart upon recovery-critical for unattended industrial equipment where mains fluctuations are common.

What packaging and thermal characteristics define the MC68HC908AB32CFU?

The MC68HC908AB32CFU is supplied in a 48-pin LQFP package (7 mm × 7 mm, 0.5 mm pitch) with an exposed thermal pad. Its rated ambient operating temperature range is –40 °C to +85 °C, and it supports junction temperatures up to +125 °C. Thermal resistance (θ_JA) is 45 °C/W under JEDEC-standard 2-layer board conditions, enabling convection-cooled operation in sealed enclosures.