NXP Semiconductors MC68HC908AP8CFB

Overview

MC68HC908AP8CFB from NXP Semiconductors (formerly Freescale) is an 8-bit HCS08-core microcontroller with 8 KB on-chip Flash memory, 512 bytes RAM, and integrated peripherals including SCI, SPI, I²C, ADC, TIM, and TBM modules. It operates at up to 8 MHz CPU frequency, supports 3.0–5.5 V supply, and features low-power wait/stop modes - used in industrial sensor nodes and appliance control panels requiring deterministic real-time response.

For engineers reviewing the MC68HC908AP8CFB datasheet, MC68HC908AP8CFB pinout, MC68HC908AP8CFB application, or MC68HC908AP8CFB equivalent, key selection criteria include its 20-pin SOIC package, internal PLL clock generation, 8-channel 8-bit ADC with programmable conversion timing, and ROM-resident monitor for in-system programming without external debugger.

Technical Context

The MC68HC908AP8CFB implements the HCS08 CPU core with a 16-bit address bus and Harvard architecture, executing instructions in single-cycle (most) or two-cycle (branch) timing. Its Clock Generator Module (CGM) integrates a PLL with programmable multiplier (×1 to ×32), enabling precise bus clock derivation from internal RC or external crystal sources.

Peripheral integration includes a 16-bit Timer Interface Module (TIM) with input capture, output compare, and PWM capability; a Multi-Master I²C interface (MMIIC); and an 8-channel Analog-to-Digital Converter with configurable sample time and reference selection (VDD or internal bandgap). All modules are register-mapped into the MCU's memory space and support interrupt-driven operation.

Key Specifications

Pinout & Package

MC68HC908AP8CFB is housed in a 20-pin Small Outline Integrated Circuit (SOIC) package with 0.3 inch body width and 1.27 mm pitch. The package provides thermal and mechanical reliability for industrial ambient temperatures (–40°C to +85°C).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC9RS08KA8CFD, the MC68HC908AP8CFB offers superior timing precision via PLL and richer peripheral set; versus S9KEAZ8AMLH, it delivers proven industrial reliability in smaller footprint and lower power at the expense of 32-bit scalability.

Availability

MC68HC908AP8CFB is available at Aetrix Electronics and suitable for industrial sensor nodes, home appliance control panels, smart thermostat interfaces, and LED lighting dimmers requiring stable component supply across extended product lifecycles.

Supply support for MC68HC908AP8CFB 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 applications, with roots in Freescale's legacy microcontroller expertise.

The MC68HC908AP8CFB belongs to the HCS08 family - designed specifically for cost-sensitive, low-power embedded control applications demanding high integration, robustness, and long-term availability in harsh environments.

FAQ

What is the maximum operating frequency of the MC68HC908AP8CFB?

The MC68HC908AP8CFB supports a maximum bus clock frequency of 8 MHz, achievable via its integrated PLL circuit configured with appropriate multiplier and reference divider settings. This corresponds to ~8 million instructions per second (MIPS) execution throughput. The PLL accepts input clocks from 100 kHz to 4 MHz and scales them up to generate the final bus clock, enabling precise timing control without external high-frequency crystals.

Does the MC68HC908AP8CFB include on-chip debug capability?

Yes, the MC68HC908AP8CFB includes a 2 KB ROM-resident Monitor (MON) that provides full in-system programming and debugging via the SCI interface. This allows flash memory erasure, programming, memory read/write, and register inspection without requiring external JTAG or BDM hardware - significantly reducing development and field service costs.

What low-power modes does the MC68HC908AP8CFB support?

The MC68HC908AP8CFB supports two primary low-power modes: Wait Mode (CPU halted, peripherals active, ~100 µA at 3 V) and Stop Mode (all clocks stopped except LVI and reset logic, ~1.0 µA at 3 V). Wake-up from Stop Mode is possible via IRQ, KBI, or reset; both modes retain RAM contents and allow rapid resumption of operation.

Can the MC68HC908AP8CFB operate from a 3.3 V supply?

Yes, the MC68HC908AP8CFB is fully specified for operation across 3.0 V to 5.5 V, making it compatible with standard 3.3 V logic systems. At 3.3 V, it maintains full functionality including ADC accuracy, PLL lock range, and I/O drive strength - verified in Freescale's electrical specifications tables for both 3 V and 5 V operation.

Is there hardware support for I²C communication on the MC68HC908AP8CFB?

Yes, the MC68HC908AP8CFB integrates a Multi-Master IIC Interface (MMIIC) module supporting standard-mode (100 kbps) and fast-mode (400 kbps) I²C protocols. It includes hardware arbitration, clock stretching, and slave address matching - enabling robust communication with sensors, EEPROMs, and other I²C peripherals without CPU intervention.