NXP Semiconductors MC908QT1ACPE

Overview

MC908QT1ACPE from Freescale Semiconductor is an 8-bit M68HC08 core microcontroller with 1 KB on-chip FLASH memory, 64 bytes RAM, and integrated peripherals including ADC10, Auto Wakeup Module (AWU), COP watchdog, and keyboard interrupt module. It operates at up to 8 MHz bus frequency, supports internal RC or external crystal oscillator, and targets low-cost embedded control in consumer and industrial applications such as appliance timers and sensor interfaces.

For engineers reviewing the MC908QT1ACPE datasheet, MC908QT1ACPE pinout, MC908QT1ACPE application, or MC908QT1ACPE equivalent, this page delivers verified technical context, package mapping, security byte configuration requirements, FLASH protection behavior, and validated alternative options for legacy design continuity and supply chain resilience.

Technical Context

The MC908QT1ACPE implements the M68HC08 CPU core with Harvard architecture, 16-bit address space, and instruction set compatible with HC05 derivatives. Its memory map includes 1 KB FLASH (user-programmable, block-protectable), 64-byte RAM, and 32-byte register file. The device uses a dual-clock system: BUSCLKX4 for internal timing and BUSCLKX2 for peripheral synchronization.

Security enforcement occurs during monitor mode entry: host must supply eight user-defined bytes matching locations $FFF6–$FFFD; entry is denied if five or more of those bytes are $00. FLASH programming and erasure follow SuperFlash® technology licensed from SST, enabling single-voltage operation and endurance of ≥10,000 write/erase cycles.

Key Specifications

Pinout & Package

MC908QT1ACPE is housed in a 16-pin DIP (Dual In-line Package) with 0.3-inch body width and through-hole mounting. Pin assignments follow the MC68HC908QTA family standard layout, with dedicated I/O ports, oscillator inputs, reset, IRQ, and power pins.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC68HC908QT1A, MC908QT1ACPE adds mandatory security byte validation to prevent unauthorized monitor access; compared with MC908QY1ACPE, it trades DAC capability for double the FLASH capacity-making it optimal for firmware-rich, security-sensitive embedded timers and controllers.

Availability

MC908QT1ACPE is available at Aetrix Electronics and suitable for home appliance timers, industrial sensor interfaces, and legacy panel controller replacements requiring stable component supply and long-term lifecycle support.

Supply support for MC908QT1ACPE 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) was a leading designer of embedded processors, analog, and connectivity solutions for automotive, industrial, and consumer markets.

The MC68HC908QTA/QYA family-including MC908QT1ACPE-was engineered for cost-sensitive, low-power 8-bit control applications where small footprint, integrated peripherals, and FLASH-based field-upgradability were essential.

FAQ

What is the maximum operating frequency of the MC908QT1ACPE?

The MC908QT1ACPE supports a maximum bus frequency of 8 MHz (BUSCLKX2). This is achieved using either the internal RC oscillator (calibrated to ±2% via TRIM register) or an external crystal up to 8 MHz connected to XTAL/EXTAL pins. The internal BUSCLKX4 signal runs at 16 MHz for CPU timing, while peripherals synchronize to BUSCLKX2.

How does the security feature work on the MC908QT1ACPE?

The MC908QT1ACPE enforces security during monitor mode entry: the host must transmit eight bytes matching the values stored at FLASH addresses $FFF6–$FFFD. If five or more of those bytes are $00, monitor mode entry is denied. This prevents unauthorized firmware extraction and requires users to program non-zero values into those locations-even if unused-as stated in the Freescale addendum.

What package type is used for the MC908QT1ACPE?

The MC908QT1ACPE is supplied in a 16-pin plastic Dual In-line Package (DIP) with 0.3-inch body width and through-hole leads. This package matches the pinout and mechanical dimensions of other members of the MC68HC908QTA family, enabling drop-in replacement in legacy designs originally specified for MC68HC908QT1A or MC68HC908QY1A.

Does the MC908QT1ACPE include an analog-to-digital converter?

Yes, the MC908QT1ACPE integrates the ADC10 module-a 10-bit successive-approximation analog-to-digital converter with eight input channels. Inputs are shared with PORTA pins (AD0–AD7), and conversion is controlled via ADSCR, ADRH, ADRL, and ADCLK registers. Reference voltages (VREFH/VREFL) may be internally derived or externally supplied.

Can the MC908QT1ACPE operate from a single 3.3 V supply?

Yes, the MC908QT1ACPE operates over a supply range of 2.7 V to 5.5 V, making it fully compatible with 3.3 V systems. All I/O pins are 5 V tolerant when configured as inputs, and internal peripherals-including ADC10, AWU, and COP-function correctly across this voltage range without external level-shifting components.