NXP Semiconductors MC908AP8ACFBE

Overview

MC908AP8ACFBE from Freescale Semiconductor 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 (8-channel, 10-bit), and a 16-bit TIM module. It operates at up to 8 MHz bus frequency, supports 2.7–5.5 V supply, and targets embedded control in industrial sensors, motor drives, and appliance subsystems.

For engineers reviewing the MC908AP8ACFBE datasheet, MC908AP8ACFBE pinout, MC908AP8ACFBE application, or MC908AP8ACFBE equivalent, key selection criteria include its 20-pin SOIC package, internal PLL clock generation, low-power stop/wait modes, and factory-programmed monitor ROM for in-system programming via SCI.

Technical Context

The MC908AP8ACFBE implements the HCS08 CPU core with enhanced addressing modes and a 16-level hardware stack. Its Clock Generator Module (CGM) integrates a PLL with programmable multipliers (×1 to ×32) and reference dividers, 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 24 vectors, and power management with configurable wait/stop modes. The ADC uses a dedicated 2.5 V internal reference and supports software- or timer-triggered conversions with 12 µs typical conversion time.

Key Specifications

Pinout & Package

MC908AP8ACFBE is housed in a 20-pin SOIC (Small Outline Integrated Circuit) package with 16 usable I/O pins, two power supply pins (VDD/VSS), and dedicated oscillator, reset, and programming interface pins.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC908AP16ACFBE and MC908AP32ACFBE, the MC908AP8ACFBE delivers optimal cost-performance balance for fixed-function controllers where code size remains under 7.5 KB and RAM usage stays below 450 bytes-avoiding over-provisioned memory that increases unit cost without design benefit.

Availability

MC908AP8ACFBE is available at Aetrix Electronics and suitable for industrial sensor nodes, smart appliance control panels, DC motor speed controllers, and energy meter subsystems requiring stable component supply and long-term manufacturability.

Supply support for MC908AP8ACFBE 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 mixed-signal microcontrollers for automotive and industrial markets, emphasizing robustness, low-power operation, and toolchain maturity.

The MC908AP8ACFBE belongs to the HCS08-based AP-family, designed specifically for cost-sensitive, high-reliability embedded control applications requiring integrated analog peripherals, secure in-field updates, and deterministic real-time response.

FAQ

What is the maximum operating frequency of the MC908AP8ACFBE?

The MC908AP8ACFBE achieves a maximum bus frequency of 8 MHz, derived either directly from the internal oscillator or via its integrated PLL circuit configured with appropriate multiplier and reference divider settings. This frequency governs instruction execution speed, peripheral timing, and ADC conversion rate. The actual achievable frequency depends on supply voltage and temperature conditions per the electrical specifications table in the official datasheet.

Does the MC908AP8ACFBE support in-system programming without external hardware?

Yes, the MC908AP8ACFBE includes a factory-programmed 256-byte monitor ROM that enables in-system programming via its SCI interface. Using standard UART signals (TXD/RXD), users can reprogram the 8 KB Flash memory without requiring a dedicated programmer-ideal for field firmware updates and low-volume manufacturing. The MC908AP8ACFBE monitor mode supports checksum verification and block erase commands.

How many analog input channels does the ADC in the MC908AP8ACFBE support?

The MC908AP8ACFBE features an 8-channel, 10-bit successive approximation ADC. All eight channels are multiplexed onto Port A pins (PTA0–PTA7), with software-selectable gain and reference options. Conversion time is typically 12 µs per sample, and triggers may originate from software, TIM overflow, or external events-enabling synchronized sampling in motor control or sensor acquisition applications.

What low-power modes are available on the MC908AP8ACFBE?

The MC908AP8ACFBE supports two primary low-power modes: Wait Mode (CPU halted, peripherals active, wake via IRQ/KBI) and Stop Mode (all clocks disabled except LVI and reset logic, wake only via RESET or IRQ). Both modes reduce current consumption to sub-10 µA levels, making the MC908AP8ACFBE suitable for battery-powered sensor nodes where duty-cycled operation is required.

Is the MC908AP8ACFBE pin-compatible with other devices in the AP-family?

Yes, the MC908AP8ACFBE shares identical pinout and package (20-pin SOIC) with MC908AP16ACFBE, MC908AP32ACFBE, and MC908AP64ACFBE. This allows hardware design reuse across variants-only Flash/RAM capacity differs. Firmware compatibility is maintained within the HCS08 instruction set, though memory-mapped register addresses remain consistent across the family, simplifying migration paths.