NXP Semiconductors MC908QT2ACDWER

Overview

MC908QT2ACDWER from Freescale Semiconductor is an 8-bit HCS08-core microcontroller with 2 KB on-chip FLASH, 128 B RAM, and integrated 10-bit ADC, AWU, COP watchdog, and LVI circuitry. It operates at up to 8 MHz bus frequency, supports monitor mode programming via on-chip serial interface, and targets low-power embedded control in industrial sensors and appliance subsystems.

For engineers reviewing the MC908QT2ACDWER datasheet, MC908QT2ACDWER pinout, MC908QT2ACDWER application, or MC908QT2ACDWER equivalent, this page delivers verified functional identity, validated package mapping (SOIC-20), confirmed security byte handling ($FFF6–$FFFD), and real-world design constraints for flash protection, oscillator trimming, and wake-up interrupt latency.

Technical Context

The MC908QT2ACDWER implements the HCS08 CPU core with 16-bit address space, supporting indexed, extended, and relative addressing modes. Its memory map includes 2 KB FLASH (user-programmable, block-protectable), 128 B RAM, and 32 B EEPROM emulation space. The internal oscillator is factory-trimmed and supports dynamic switching to external crystal or RC sources.

Peripheral integration includes a 10-bit ADC with 8 input channels, Auto Wakeup Module with programmable timeout (1–65535 bus cycles), Computer Operating Properly (COP) watchdog with selectable timeout (0.5 ms–1.0 s), and Low-Voltage Inhibit with hysteresis and forced reset capability. All modules operate under Wait/Stop low-power modes with configurable wake-up sources.

Key Specifications

Pinout & Package

MC908QT2ACDWER is housed in a 20-pin SOIC (Small Outline Integrated Circuit) package with 0.300-inch body width and standard JEDEC MS-013AC footprint. Pin assignments follow the MC68HC908QTA family layout, with dedicated VDD/VSS, RESET, IRQ, KBI inputs, ADC channel pins, and bidirectional I/O ports.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC908QT2ACDWER, the QT4 variant offers doubled FLASH capacity in identical form factor for firmware growth, while the QY2 variant trades compactness for I/O expansion - both retain full register compatibility and require no code modification for shared functionality.

Availability

MC908QT2ACDWER is available at Aetrix Electronics and suitable for industrial sensor nodes, home appliance subsystems, smart thermostat interfaces, and LED lighting drivers requiring stable component supply and long-term manufacturability.

Supply support for MC908QT2ACDWER 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, low-power embedded systems.

The MC68HC908QTA family - including MC908QT2ACDWER - was designed for appliance control, sensor interfacing, and industrial automation where small footprint, integrated analog peripherals, and robust flash security are essential.

FAQ

What is the maximum bus frequency supported by the MC908QT2ACDWER?

The MC908QT2ACDWER supports a maximum bus frequency of 8 MHz. This is achieved using the internal oscillator (trimmed RC source) or an external crystal/RC network. The actual bus speed depends on configuration of the System Integration Module (SIM) registers, particularly the prescaler settings and oscillator source selection. At 8 MHz bus frequency, instruction execution time is optimized for real-time control tasks such as motor commutation or sensor sampling with sub-millisecond latency.

How does the security feature work for monitor mode entry on the MC908QT2ACDWER?

The MC908QT2ACDWER enforces security during monitor mode entry by requiring the host to transmit eight bytes that exactly match the values stored at memory locations $FFF6–$FFFD. If five or more of those bytes are zero, monitor mode entry is denied - preventing accidental or brute-force access. These locations must be programmed with non-zero values during production programming, even if unused for vector storage, to maintain security integrity across the device's lifetime.

Can the MC908QT2ACDWER operate from a 3.3 V supply?

Yes, the MC908QT2ACDWER operates across a 2.7–5.5 V supply range, making 3.3 V fully compliant. At 3.3 V, the internal oscillator maintains ±2% accuracy (25°C), and all I/O pins are 5 V tolerant when configured as inputs. The LVI threshold remains fixed at 2.5 V, ensuring reliable brown-out detection even with 3.3 V nominal rails - critical for systems powered by regulated DC-DC converters.

What peripheral modules are integrated into the MC908QT2ACDWER?

The MC908QT2ACDWER integrates an 8-bit HCS08 CPU core, 2 KB FLASH, 128 B RAM, 10-bit ADC with 8 channels, Auto Wakeup Module (AWU), Computer Operating Properly (COP) watchdog, Low-Voltage Inhibit (LVI), Keyboard Interrupt (KBI), External Interrupt (IRQ), and System Integration Module (SIM). It lacks on-chip UART/SCI but supports bit-banged serial communication using port pins and timer resources.

Is the MC908QT2ACDWER pin-compatible with other members of the QTA family?

Yes, the MC908QT2ACDWER is pin-compatible with MC908QT1ACDWER and MC908QT4ACDWER in the same 20-pin SOIC package. All share identical pin functions, electrical characteristics, and register-level compatibility. Firmware written for one can run unmodified on another, though FLASH size differences (1 KB vs. 2 KB vs. 4 KB) must be accounted for during linking and programming.