NXP Semiconductors MC68HC908AP8CB

Overview

MC68HC908AP8CB from Freescale Semiconductor is an 8-bit HCS08-core microcontroller with 8 KB on-chip Flash memory, 256 B RAM, and integrated peripherals including a 10-bit ADC (8 channels), SCI, SPI, I²C, TIM, and TBM modules. It operates at up to 8 MHz CPU frequency with internal oscillator support and features low-voltage inhibit (LVI), COP watchdog, and stop/wait power-saving modes. It targets cost-sensitive embedded control in appliance motor drives and industrial sensor interfaces.

For engineers reviewing the MC68HC908AP8CB datasheet, MC68HC908AP8CB pinout, MC68HC908AP8CB application, or MC68HC908AP8CB equivalent, this page delivers verified technical context, package mapping, functional specifications, and real-world use cases - all grounded in Freescale's Rev. 4 datasheet and official ordering information for the AP8 variant.

Technical Context

The MC68HC908AP8CB implements the HCS08 CPU core with 16-bit address space, supporting indexed, extended, and relative addressing. Its Clock Generator Module (CGM) integrates a PLL for frequency multiplication and supports multiple clock sources: internal RC oscillator (1–8 MHz), external crystal (up to 8 MHz), or external clock input.

Peripherals include a 10-bit successive-approximation ADC with programmable sample time and conversion trigger sources (software, TIM, SCI), dual asynchronous serial interfaces (SCI and IRSCI), and a multi-master I²C module compliant with Philips I²C-bus specification. The device uses SuperFlash® technology for Flash endurance (>10k erase/write cycles) and data retention (>10 years).

Key Specifications

Pinout & Package

MC68HC908AP8CB is housed in a 44-pin QFP (Quad Flat Package) with 0.8 mm lead pitch and 10 mm × 10 mm body size. Pin functions are defined per Freescale's "Pin Assignment" (Section 1.4) and "Pin Functions" (Section 1.5) in Rev. 4 datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC68HC908AP8CB, MC9RS08KA8 offers simpler architecture and lower power but sacrifices hardware PWM and I²C; MC9S08QG8 adds CAN and larger RAM at the cost of increased footprint and design complexity - making MC68HC908AP8CB optimal for self-contained, cost-sensitive control with mixed serial and analog I/O.

Availability

MC68HC908AP8CB is available at Aetrix Electronics and suitable for appliance motor control, industrial sensor interface, smart power outlet, and automotive body controller subsystems requiring stable component supply and long-term manufacturability.

Supply support for MC68HC908AP8CB 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) pioneered 8-bit microcontrollers for automotive and industrial markets, emphasizing robustness, mixed-signal integration, and toolchain maturity.

The MC68HC908AP family was designed for cost-effective, single-chip embedded control in appliances and industrial equipment - prioritizing Flash flexibility, analog integration, and low-power operation over raw performance.

FAQ

What is the maximum operating frequency of the MC68HC908AP8CB?

The MC68HC908AP8CB supports a maximum CPU bus frequency of 8 MHz. This is achieved using the on-chip PLL to multiply the internal RC oscillator (nominal 1–8 MHz) or an external crystal (1–8 MHz). The PLL allows stable high-speed operation without requiring an external clock generator, simplifying board design while maintaining timing accuracy for real-time control tasks in the MC68HC908AP8CB.

Does the MC68HC908AP8CB include a hardware I²C interface?

Yes, the MC68HC908AP8CB integrates a multi-master I²C interface compliant with the Philips I²C-bus specification. It supports standard-mode (100 kbps) and fast-mode (400 kbps) operation, with dedicated SDA and SCL pins on Port D (PTD0/PTD1). The module handles arbitration, clock stretching, and ACK/NACK generation in hardware - offloading these tasks from the CPU and ensuring reliable communication with sensors or displays in the MC68HC908AP8CB-based system.

How much Flash memory does the MC68HC908AP8CB have, and is it reprogrammable in-circuit?

The MC68HC908AP8CB contains 8 KB of on-chip Flash memory implemented with SuperFlash® technology. It is fully reprogrammable in-circuit via the built-in Monitor ROM (MON), which provides EE_WRITE and EE_READ routines accessible through the SCI interface. No external high-voltage programmer is needed - firmware updates can be performed in the field using standard UART communication, enabling remote maintenance and feature upgrades for deployed MC68HC908AP8CB units.

What power-saving modes are supported by the MC68HC908AP8CB?

The MC68HC908AP8CB supports two low-power modes: Wait Mode (CPU halted, peripherals active) and Stop Mode (all clocks stopped except optional RTC or LVI). In Stop Mode, typical current consumption is 1 µA at 3 V, and wake-up can occur via RESET, IRQ, KBI, or SCI start-bit detection. These modes allow battery-powered or energy-harvesting applications using the MC68HC908AP8CB to extend operational life while retaining fast response to external events.

Can the MC68HC908AP8CB generate PWM signals without CPU intervention?

Yes, the MC68HC908AP8CB includes a Timer Interface Module (TIM) with two independent output compare channels (OC1 and OC2) capable of generating hardware PWM signals. Once configured, the TIM autonomously toggles output pins based on counter match events - freeing the CPU for other tasks. Duty cycle and period are controlled via dedicated registers (e.g., TCx, TCMODx), and the MC68HC908AP8CB supports both buffered and unbuffered PWM modes for glitch-free updates during runtime.