NXP Semiconductors MC908EY8AMFJE

Overview

MC908EY8AMFJE from Freescale Semiconductor is an 8-bit HCS08-core microcontroller with 8 KB on-chip FLASH, 512 B RAM, and integrated peripherals including ADC10 (10-bit, 8-channel), ESCI, SPI, BEMF counter, and ICG clock generator. It operates from 2.7–5.5 V, supports -40°C to +125°C industrial temperature range, and targets motor control and embedded sensing applications.

For engineers reviewing the MC908EY8AMFJE datasheet, MC908EY8AMFJE pinout, MC908EY8AMFJE application, or MC908EY8AMFJE equivalent, key selection criteria include FLASH security byte validation ($FFF6–$FFFD), internal clock trimming capability, 10-bit ADC resolution with analog reference pins (VREFH/VREFL), and support for monitor mode entry with eight-byte security match.

Technical Context

The MC908EY8AMFJE implements the HCS08 CPU core with 16-bit address space, supports WAIT/STOP low-power modes, and features a digitally controlled oscillator (DCO) with frequency trimming via ICG registers. Its security architecture requires user-programmed 8-byte pattern at $FFF6–$FFFD to enable monitor mode access.

It integrates an ADC10 module with programmable sample time, configurable input channels (AD0–AD7), and dedicated analog supply (VDDA/VSSA) and reference pins (VREFH/VREFL). The BEMF counter supports brushless DC motor commutation timing via TACH0/TACH1 inputs.

Key Specifications

Pinout & Package

MC908EY8AMFJE is housed in a 48-pin QFP (MFJE) package with 3.0 × 3.0 mm body, 0.5 mm pitch, and exposed thermal pad. Pin functions follow standard HCS08 EY-series assignment per Rev. 2 datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC908EY16AMFJE, the MC908EY8AMFJE trades FLASH capacity for lower cost and smaller footprint while retaining identical peripheral functionality; versus S908EY8AKFJE, it provides full I/O access including critical motor control signals, making it the only option supporting BEMF counter and dual UART interfaces.

Availability

MC908EY8AMFJE is available at Aetrix Electronics and suitable for motor control, industrial sensing, automotive subsystems, and embedded power management requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MC908EY8AMFJE 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) designed high-reliability microcontrollers for automotive, industrial, and appliance markets with emphasis on mixed-signal integration and robustness.

The MC68HC908EY family was engineered for cost-sensitive, real-time embedded control tasks demanding analog sensing, motor timing, and secure firmware update capability - particularly in BLDC motor drives and condition-monitoring systems.

FAQ

What is the FLASH memory size and protection capability of the MC908EY8AMFJE?

The MC908EY8AMFJE contains 8 KB of on-chip FLASH memory with configurable block protection via the FLASH Block Protect Register. Protection can be applied to individual 512-byte blocks, preventing accidental overwrite or read-out during normal operation or debug sessions. This feature enhances firmware integrity in field-deployed devices.

How does the security feature work for monitor mode access on the MC908EY8AMFJE?

The MC908EY8AMFJE requires eight user-defined security bytes programmed into FLASH addresses $FFF6–$FFFD. During monitor mode entry, the host must transmit matching bytes; if five or more are $00, monitor mode is denied. This prevents unauthorized firmware extraction while allowing legitimate development access when properly configured.

Which analog input channels are available on the MC908EY8AMFJE and how are they mapped?

The MC908EY8AMFJE provides eight 10-bit ADC input channels (AD0–AD7), mapped to Port B pins PTB0 through PTB7. Each channel supports single-ended or differential measurement, with dedicated analog supply (VDDA/VSSA) and reference pins (VREFH/VREFL) to ensure signal integrity independent of digital switching noise.

What is the role of the BEMF counter module in the MC908EY8AMFJE and which pins support it?

The BEMF counter module in the MC908EY8AMFJE detects back-electromotive force zero-crossings for brushless DC motor commutation. It uses dedicated hardware inputs TACH0 and TACH1, assigned to PTD0 and PTD1 respectively, enabling precise rotor position tracking without CPU intervention or timer resource consumption.

Does the MC908EY8AMFJE support both internal and external clock sources, and how is clock selection managed?

Yes, the MC908EY8AMFJE supports internal DCO and external crystal/resonator clocks via its Internal Clock Generator (ICG) module. Clock source selection is controlled by CONFIG registers and the ICG Control Register, allowing dynamic switching between sources and enabling fail-safe clock monitoring with automatic fallback to internal DCO upon external clock failure.