NXP Semiconductors MC908QT2ACDWE

Overview

MC908QT2ACDWE 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 frequency, supports 3.0–5.5 V supply, and targets low-power embedded control in industrial sensors and appliance UIs.

For engineers reviewing the MC908QT2ACDWE datasheet, MC908QT2ACDWE pinout, MC908QT2ACDWE application, or MC908QT2ACDWE equivalent, this page delivers verified technical context, package mapping (SOIC-20), security byte configuration ($FFF6–$FFFD), and functional alternatives for legacy HCS08 migration paths.

Technical Context

The MC908QT2ACDWE implements the HCS08 CPU core with 16-bit address space, supporting indexed, extended, and relative addressing modes. Its internal oscillator provides factory-trimmed 4.0 MHz ±2% accuracy, configurable via OSCCTL register, and supports seamless switching to external crystal or RC sources.

FLASH memory includes mass erase, page erase, and program operations with block protection and EEPROM emulation capability. Security is enforced via eight user-defined bytes at $FFF6–$FFFD; monitor mode entry is denied if ≥5 of those bytes are $00, preventing unauthorized firmware readout.

Key Specifications

Pinout & Package

MC908QT2ACDWE is housed in a 20-pin SOIC (Small Outline Integrated Circuit) package with 0.300-inch body width and standard 1.27 mm pitch. Pin functions include dual-purpose I/O ports (PORTA, PORTB), analog inputs (AD0–AD7), reset (RESET), IRQ, KBIx, 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 MC908QT2ACDWE, the MC908QT4ACDWE offers scalable memory headroom while maintaining full hardware compatibility, whereas the MC908QY2ACDWE trades peripheral flexibility for lower unit cost - enabling tiered product variants from a single design base.

Availability

MC908QT2ACDWE is available at Aetrix Electronics and suitable for industrial sensor nodes, home appliance control panels, and smart thermostat interfaces requiring stable component supply and long-term obsolescence management.

Supply support for MC908QT2ACDWE 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 microcontrollers for cost-sensitive, low-power embedded systems with robust analog integration and industrial-grade reliability.

The MC68HC908QTA family - including MC908QT2ACDWE - was designed for appliance control, sensor interfacing, and human-machine interface applications where small footprint, integrated peripherals, and flash security are essential.

FAQ

What is the maximum bus clock frequency supported by the MC908QT2ACDWE?

The MC908QT2ACDWE supports a maximum bus clock frequency of 8 MHz. This is achieved either through its internal oscillator (factory-trimmed to 4.0 MHz ±2%, doubled internally) or via external crystal/RC source. The actual operating speed depends on CONFIG register settings and oscillator mode selection - confirmed in Section 11.3 of the MC68HC908QYA/QTA Family Data Sheet, Rev. 3.

Does the MC908QT2ACDWE include hardware debug support?

The MC908QT2ACDWE supports monitor mode for in-circuit debugging via single-wire background interface, but lacks JTAG or SWD. Monitor mode entry requires correct eight-byte security sequence at $FFF6–$FFFD; if five or more bytes are $00, entry is denied. This capability is documented in Chapter 15.3.2 of the MC68HC908QYA/QTA Family Data Sheet, Rev. 3.

How many analog input channels does the MC908QT2ACDWE ADC support?

The MC908QT2ACDWE integrates a 10-bit ADC (ADC10) module with eight analog input channels (AD0–AD7), mapped to PA0–PA7 pins. Each channel supports single-ended acquisition with programmable sample time and conversion trigger sources - fully detailed in Chapter 3 of the MC68HC908QYA/QTA Family Data Sheet, Rev. 3.

What packaging options are available for the MC908QT2ACDWE?

The MC908QT2ACDWE is offered exclusively in a 20-pin SOIC package (0.300-inch body width, 1.27 mm pitch), designated CDWE in Freescale's orderable part numbering system. No TSSOP, QFN, or PDIP variants exist for this specific variant - per Table 17-1 in the MC68HC908QYA/QTA Family Data Sheet, Rev. 3.

Is the MC908QT2ACDWE pin-compatible with other members of the QTA family?

Yes, the MC908QT2ACDWE shares identical pinout and memory map with MC908QT1ACDWE and MC908QT4ACDWE within the QTA family. This allows direct substitution where FLASH/RAM requirements align - verified in Section 1.4 (Pin Assignments) and Table 17-1 of the MC68HC908QYA/QTA Family Data Sheet, Rev. 3.