NXP Semiconductors MC908GR16ACFAE

Overview

MC908GR16ACFAE from Freescale Semiconductor is an 8-bit HCS08 microcontroller featuring 16 KB on-chip Flash memory, 512 B RAM, a 10-bit ADC with 8 input channels, two 16-bit timer modules (TIM1/TIM2), and integrated ESCI and SPI serial interfaces. It operates at up to 8 MHz bus frequency and supports low-power Wait/Stop modes for battery-powered control applications such as motor drive supervision and sensor interface modules.

For engineers reviewing the MC908GR16ACFAE datasheet, MC908GR16ACFAE pinout, MC908GR16ACFAE application, or MC908GR16ACFAE equivalent, key selection criteria include Flash endurance (100k erase/write cycles), COP watchdog timing flexibility, PLL-based clock generation with external crystal support, and KBI-optimized keyboard scanning capability in embedded HMI systems.

Technical Context

The MC908GR16ACFAE implements the CPU08 core with 8-bit ALU, 16-bit index register, and condition-code-based branching. Its Clock Generator Module (CGM) integrates a crystal oscillator, PLL with programmable multiplier (×1–×32), and VCO range select-enabling stable internal bus clocks from 32 kHz to 8 MHz using external crystals or RC networks.

Peripheral integration includes dual 16-bit timers with input capture/output compare, ESCI supporting asynchronous UART mode, SPI master/slave operation, and a Keyboard Interrupt Module (KBI) with configurable debounce and wake-on-key functionality-designed for real-time I/O management in resource-constrained industrial controls.

Key Specifications

Pinout & Package

MC908GR16ACFAE is housed in a 64-pin QFP (Quad Flat Package) with 0.5 mm pitch and exposed thermal pad. Pin assignments follow standard HCS08 I/O port mapping with dedicated analog, oscillator, reset, and interrupt pins.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit microcontroller applications.

Compared with MC908GR16ACFAE, MC908AP64CFUE offers greater program storage and CAN capability at the expense of KBI and higher BOM cost, while MC9S08QG8CDTE delivers identical peripheral functionality in a smaller package with less Flash-making it suitable for simplified HMI designs where firmware size is under 8 KB.

Availability

MC908GR16ACFAE is available at Aetrix Electronics and suitable for motor control interface, sensor data acquisition, industrial keypad terminal, and legacy protocol bridge applications requiring stable component supply and long-term industrial lifecycle support.

Supply support for MC908GR16ACFAE 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 MCU architectures for cost-sensitive industrial and automotive applications with robust flash technology and mixed-signal integration.

The MC908GR16ACFAE belongs to the HCS08 family, designed specifically for embedded control tasks demanding reliable Flash endurance, low-power operation, and hardware-accelerated I/O management in harsh environments.

FAQ

What is the maximum operating frequency of the MC908GR16ACFAE?

The MC908GR16ACFAE achieves a maximum bus frequency of 8 MHz, derived from its integrated PLL circuit. This frequency is programmable via the PLL Multiplier Select Registers and supported by external crystal inputs ranging from 32 kHz to 8 MHz. The actual achievable speed depends on VDD voltage (minimum 4.5 V required for full 8 MHz operation) and ambient temperature per the Electrical Specifications chapter of the MC68HC908GR16A datasheet Rev. 1.0.

Does the MC908GR16ACFAE support in-system programming (ISP)?

Yes, the MC908GR16ACFAE supports in-system programming using its on-chip SuperFlash® memory. Programming is performed via the background debug mode (BDM) interface using standard Freescale BDM tools. The Flash architecture allows byte/page/sector erase and write operations without external high-voltage supplies, enabling field firmware updates and configuration changes directly within the target application.

How does the Keyboard Interrupt Module (KBI) function on the MC908GR16ACFAE?

The KBI on the MC908GR16ACFAE monitors Port A pins (PTA0–PTA7) for key press/release transitions with configurable debounce filtering. It operates autonomously-requiring no CPU polling-and generates interrupts only upon validated edge events. The KBI Status and Control Register (KBSCR) enables individual pin masking, edge polarity selection, and interrupt flag clearing, making it ideal for low-overhead human-machine interface designs.

What low-power modes are available on the MC908GR16ACFAE and how do they differ?

The MC908GR16ACFAE provides two hardware-supported low-power states: Wait mode halts the CPU while keeping peripherals (ADC, timers, serial interfaces) operational using the CGM clock; Stop mode disables all clocks except the LVI and optional RTC oscillator, reducing current draw to under 1 µA. Both modes retain RAM contents and support wake-up via IRQ, KBI, or reset events, with Stop mode offering deeper power savings at the cost of longer wake-up latency.

Is the MC908GR16ACFAE pin-compatible with other HCS08 devices?

The MC908GR16ACFAE uses a 64-pin QFP package with pin assignments aligned to the HCS08 family's standard I/O port layout (e.g., PTA–PTE ports, OSC1/OSC2, RST). While not universally pin-compatible across all HCS08 variants, it shares identical pinouts with the MC908AP64CFUE and MC908GR32ACFAE-enabling direct PCB reuse when migrating between Flash sizes within the same package variant.