NXP Semiconductors MC908QT2ACFQE

Overview

MC908QT2ACFQE from Freescale Semiconductor is an 8-bit HCS08-core microcontroller with 2 KB Flash, 128 B RAM, and integrated ADC10, AWU, COP watchdog, LVI, and keyboard interrupt modules. It operates at up to 8 MHz bus speed, supports 5 V operation, and targets low-cost embedded control in industrial sensors and appliance sub-systems.

For engineers reviewing the MC908QT2ACFQE datasheet, MC908QT2ACFQE pinout, MC908QT2ACFQE application, or MC908QT2ACFQE equivalent, key selection criteria include Flash security byte validation ($FFF6–$FFFD), internal oscillator trimming capability, 10-bit ADC with 8-channel input, AWU wake-up timing resolution, and COP timeout configurability.

Technical Context

The MC908QT2ACFQE implements the HCS08 CPU core with 16-bit address space, supporting indexed, extended, and relative addressing modes. Its memory map includes 2 KB of on-chip FLASH (with block protection and mass erase), 128 B RAM, and 48 B of direct-page registers.

It integrates a 10-bit successive-approximation ADC (ADC10) with programmable clock division, 8 analog inputs, and conversion completion interrupt. The Auto Wakeup Module (AWU) provides programmable sleep intervals using internal RC oscillator or external clock sources, enabling ultra-low-power standby operation.

Key Specifications

Pinout & Package

MC908QT2ACFQE is housed in a 20-pin SOIC package (body width 7.5 mm) with 18 I/O pins, two power pins (VDD, VSS), and dedicated oscillator pins (XTAL, EXTAL).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC908QT2ACFQE, the QT4A offers scalable Flash for evolving firmware, while the QY2A adds analog comparators for precision sensing - both retain identical pinout, clock architecture, and development tool compatibility.

Availability

MC908QT2ACFQE is available at Aetrix Electronics and suitable for industrial sensor nodes, home appliance control boards, and smart meter sub-controllers requiring stable component supply and long-term lifecycle support.

Supply support for MC908QT2ACFQE 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, cost-optimized microcontrollers for automotive, industrial, and consumer markets.

The MC68HC908QTA/QYA family delivers compact 8-bit control with integrated analog peripherals and robust low-power features for resource-constrained embedded systems.

FAQ

What is the maximum operating frequency of the MC908QT2ACFQE?

The MC908QT2ACFQE supports a maximum bus clock frequency of 8 MHz, achievable using either the internal trimmed RC oscillator or an external crystal connected to XTAL/EXTAL pins. This frequency determines instruction execution speed, ADC sampling rate, and peripheral timing - all calibrated to maintain deterministic behavior across voltage and temperature ranges.

Does the MC908QT2ACFQE support in-circuit debugging?

Yes, the MC908QT2ACFQE supports monitor mode debugging via its built-in serial monitor ROM. Entry requires correct eight-byte security key programming at $FFF6–$FFFD; monitor mode provides memory read/write, register inspection, and breakpoint-triggered execution control without requiring external JTAG hardware.

How does the Flash security feature work on the MC908QT2ACFQE?

The MC908QT2ACFQE implements Flash security by validating eight user-programmed bytes at memory addresses $FFF6–$FFFD during monitor mode entry. If five or more of those bytes are zero, monitor access is denied - preventing unauthorized firmware extraction while allowing legitimate development with properly configured keys.

Can the MC908QT2ACFQE operate from a single 5 V supply?

Yes, the MC908QT2ACFQE is specified for 4.5 V to 5.5 V operation and includes an integrated Low-Voltage Inhibit (LVI) circuit that asserts reset below ~4.0 V. This ensures reliable startup and prevents erratic behavior during brown-out conditions typical in 5 V industrial power rails.

What peripheral modules are integrated into the MC908QT2ACFQE?

The MC908QT2ACFQE integrates the HCS08 CPU core, 2 KB Flash, 128 B RAM, 10-bit ADC with 8 inputs, Auto Wakeup Module (AWU), Computer Operating Properly (COP) watchdog, Low-Voltage Inhibit (LVI), Keyboard Interrupt Module (KBI), and System Integration Module (SIM) with configuration registers - all in a single SOIC-20 package.