NXP Semiconductors MC908QT1ACDWE

Overview

MC908QT1ACDWE from Freescale Semiconductor is an 8-bit HCS08-core microcontroller with 1 KB FLASH, 64 bytes RAM, and integrated ADC10, AWU, COP watchdog, LVI, and keyboard interrupt modules. It operates at up to 8 MHz bus frequency, supports 3.0–5.5 V supply, and features on-chip oscillator trimming and monitor-mode security via $FFF6–$FFFD byte matching. It targets low-cost industrial sensor interfaces and simple embedded control.

For engineers reviewing the MC908QT1ACDWE datasheet, MC908QT1ACDWE pinout, MC908QT1ACDWE application, or MC908QT1ACDWE equivalent, this page delivers verified functional identity, validated package mapping (SOIC-16), confirmed security behavior (5+ zero-byte denial), exact memory layout, and real-world use-case context for rapid schematic integration and firmware development.

Technical Context

The MC908QT1ACDWE implements the HCS08 CPU core with 16-bit address space, supporting indexed, extended, and relative addressing modes. Its internal oscillator is factory-trimmed and user-adjustable via the OSCTRIM register, enabling stable operation without external crystal across temperature and voltage ranges.

FLASH memory includes mass erase, page erase, and byte-program capabilities, with protection enforced by the FLBPR register and security bypass requiring eight user-defined bytes at $FFF6–$FFFD. Monitor mode entry is denied if five or more of those bytes are $00 - a hardened anti-dump feature confirmed in the May 2012 Addendum.

Key Specifications

Pinout & Package

MC908QT1ACDWE is housed in a 16-pin SOIC (Small Outline Integrated Circuit) package with 1.27 mm pitch, JEDEC MS-012AC compliant, suitable for automated PCB assembly and reflow soldering.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC908QT1ACDWE, the QT2 variant offers scalable code storage without layout impact, while the QY1 provides enhanced analog front-end fidelity at the cost of slightly higher power in active ADC mode - both retain identical packaging, security model, and monitor-mode behavior.

Availability

MC908QT1ACDWE is available at Aetrix Electronics and suitable for industrial sensor interfaces, appliance control panels, smart power outlets, and legacy equipment retrofits requiring stable component supply and long-term lifecycle support.

Supply support for MC908QT1ACDWE 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 cost-sensitive industrial and consumer applications.

The MC68HC908QYA/QTA family - including MC908QT1ACDWE - was engineered for ultra-low-power, pin-constrained embedded control with integrated analog and security features, targeting replacement of discrete logic and older 8-bit MCUs.

FAQ

What is the maximum operating frequency of the MC908QT1ACDWE?

The MC908QT1ACDWE supports a maximum bus clock frequency of 8 MHz, derived from its internal oscillator (trimmed up to ±2%) or external crystal/resonator. This frequency determines instruction execution speed, ADC conversion time, and serial communication baud rates - all fully specified in the Electrical Characteristics chapter of the Rev. 3 datasheet.

Does the MC908QT1ACDWE include hardware debug support?

The MC908QT1ACDWE supports Freescale's MON08 monitor mode via the SCI interface, enabling firmware download, register inspection, and breakpoint execution. Entry requires correct eight-byte security key at $FFF6–$FFFD; monitor mode is disabled if five or more of those bytes are $00 - a documented security enhancement from the May 2012 Addendum.

How much FLASH memory does the MC908QT1ACDWE have, and is it reprogrammable in-circuit?

The MC908QT1ACDWE contains 1 KB of on-chip FLASH memory that supports in-system programming via the SCI interface in monitor mode. It permits mass erase, page erase, and byte programming operations - all controlled by dedicated FLASH registers (FSTAT, FCNFG, FLBPR) and protected by the FLBPR lock mechanism.

What peripheral modules are integrated into the MC908QT1ACDWE?

The MC908QT1ACDWE integrates an Analog-to-Digital Converter (ADC10), Auto Wakeup Module (AWU), Computer Operating Properly (COP) watchdog, Low-Voltage Inhibit (LVI), Keyboard Interrupt (KBI), and Serial Communication Interface (SCI). These peripherals operate independently of the CPU and reduce external component count for basic control tasks.

Is the MC908QT1ACDWE pin-compatible with other members of the QTA family?

Yes - the MC908QT1ACDWE shares the same SOIC-16 pinout and signal mapping with MC908QT2ACDWE and MC908QT4ACDWE. This allows direct PCB substitution within the QT-series for firmware scaling, provided FLASH usage remains within the target device's capacity and configuration bits are updated accordingly.