NXP Semiconductors MC908AP32ACFBE

Overview

MC908AP32ACFBE from Freescale Semiconductor is an 8-bit HCS08-core microcontroller with 32 KB on-chip Flash memory, 1 KB RAM, and integrated peripherals including SCI, SPI, I²C, ADC (8-channel, 10-bit), and a 16-bit TIM module. It operates at up to 40 MHz bus frequency using internal PLL clock generation and supports industrial temperature range (–40°C to +85°C) in a 64-pin QFP package. It targets embedded control applications such as motor drive interfaces and sensor-based industrial modules.

For engineers reviewing the MC908AP32ACFBE datasheet, MC908AP32ACFBE pinout, MC908AP32ACFBE application, or MC908AP32ACFBE equivalent, key selection criteria include its 32 KB Flash density, 8-channel 10-bit ADC resolution, PLL-based clock synthesis supporting 40 MHz bus speed, and native support for SCI/SPI/I²C serial protocols in a 64-pin LQFP package.

Technical Context

The MC908AP32ACFBE implements the HCS08 CPU core with enhanced addressing modes and a 16-level hardware stack. Its Clock Generator Module (CGM) integrates a phase-locked loop (PLL) with programmable multiplier (×1 to ×32) and reference divider, enabling precise bus clock derivation from internal RC or external crystal sources.

System integration includes a System Integration Module (SIM) managing reset sources (POR, LVI, COP, illegal opcode), interrupt prioritization across 27 vectors, and low-power modes (Wait/Stop). The analog subsystem features a 10-bit successive-approximation ADC with configurable sample time, conversion trigger sources (software, TIM, SCI), and built-in voltage reference.

Key Specifications

Pinout & Package

MC908AP32ACFBE is housed in a 64-pin Low-Profile Quad Flat Package (LQFP) with 0.5 mm pitch, thermally enhanced for industrial convection cooling. Pin layout supports full peripheral mapping including dual SCI channels, SPI, I²C, 8 ADC inputs, and 48 general-purpose I/O lines with configurable pull-ups.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC908AP32ACFBE, the MC908AP64ACFBE offers double Flash capacity with zero hardware change, while the S9KEAZ128AMLH delivers modern ARM performance at the cost of full software rework - making the former ideal for incremental upgrades and the latter suited for greenfield projects demanding advanced peripherals.

Availability

MC908AP32ACFBE is available at Aetrix Electronics and suitable for industrial motor control, sensor fusion nodes, smart metering systems, and legacy controller upgrades requiring stable component supply and long-term manufacturing continuity.

Supply support for MC908AP32ACFBE 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 pioneer in embedded microcontrollers, known for robust automotive and industrial-grade silicon with strong toolchain and documentation support.

The MC908AP32ACFBE belongs to the HCS08 AP-family, designed specifically for cost-sensitive, high-reliability industrial control applications requiring integrated analog peripherals, deterministic real-time response, and extended temperature operation.

FAQ

What is the maximum operating frequency of the MC908AP32ACFBE bus clock?

The MC908AP32ACFBE achieves a maximum bus clock frequency of 40 MHz using its integrated Phase-Locked Loop (PLL) circuit. This is programmable via the CGM registers and can be derived from either the internal 32.768 kHz RC oscillator or an external crystal source. The PLL supports multiplication factors from ×1 to ×32, allowing precise clock synthesis while maintaining stability across voltage and temperature variations. MC908AP32ACFBE's timing specification guarantees full functionality at this rate under industrial conditions.

Does the MC908AP32ACFBE support in-circuit debugging without external hardware?

Yes, the MC908AP32ACFBE includes a built-in Monitor ROM that enables single-wire Background Debug Mode (BDM) via the BKGD pin. This allows full read/write memory access, register inspection, breakpoint setting, and flash programming directly through the BDM interface - no external emulator or JTAG adapter required. MC908AP32ACFBE's debug architecture is fully compliant with Freescale's standard BDM protocol and supported by CodeWarrior development tools.

How many analog input channels does the ADC in the MC908AP32ACFBE support?

The MC908AP32ACFBE integrates an 8-channel, 10-bit successive-approximation ADC with dedicated input pins AD0 through AD7 mapped to Port C pins PTC0–PTC7. Each channel supports programmable sample time and conversion triggering via software command, TIM overflow, or SCI idle detection. MC908AP32ACFBE's ADC also includes an internal voltage reference option and supports differential input configurations on selected channel pairs.

Is the MC908AP32ACFBE pin-compatible with other members of the AP-family?

Yes, the MC908AP32ACFBE shares identical 64-pin LQFP packaging and pin assignments with MC908AP64ACFBE, MC908AP16ACFBE, and MC908AP8ACFBE. All AP-family variants maintain register-level compatibility across peripherals, reset behavior, and interrupt vector mapping. MC908AP32ACFBE can be substituted with these parts in existing designs - only Flash/RAM size and certain mask options differ, with no PCB or firmware changes needed for functional equivalence.

What low-power modes are available on the MC908AP32ACFBE and how do they affect peripheral operation?

The MC908AP32ACFBE supports two primary low-power modes: Wait mode halts the CPU while keeping clocks active for peripherals like TIM, SCI, and ADC, enabling wake-on-interrupt; Stop mode disables all clocks except those needed for reset and IRQ detection, reducing current draw to ~1 µA. In both modes, MC908AP32ACFBE retains RAM contents and register states. Peripheral-specific clock gating is controlled via SIM registers, allowing selective activation - for example, enabling SCI receive clock while disabling TIM during Stop mode recovery.