NXP Semiconductors MC68HC908QY2CDW

Overview

MC68HC908QY2CDW from NXP Semiconductors (formerly Freescale) is an 8-bit HCS08-core microcontroller with 2 KB FLASH, 128 B RAM, and integrated 8-channel 8-bit ADC. It features internal RC oscillator (4 MHz nominal), low-voltage inhibit (LVI), computer operating properly (COP) watchdog, and keyboard interrupt module - designed for cost-sensitive embedded control in appliance panels, industrial sensors, and battery-powered instrumentation.

For engineers reviewing the MC68HC908QY2CDW datasheet, MC68HC908QY2CDW pinout, MC68HC908QY2CDW application, or MC68HC908QY2CDW equivalent, key selection criteria include its 16-pin SOIC-W package, 2.7–5.5 V operation, on-chip oscillator trim capability, IRQ/KBI wake-up sources, and FLASH-based field programmability without external high-voltage programming.

Technical Context

The MC68HC908QY2CDW implements the HCS08 CPU core with 16-bit address space, supporting WAIT/STOP low-power modes and a configurable COP timeout (1.0–16.4 ms). Its oscillator module supports internal RC, external crystal (1–8 MHz), or external clock input, with automatic failover and trimming via OSCTRIM register at $FFC0.

Memory architecture includes 2 KB of on-chip FLASH (with block protection), 128 B RAM, and dedicated I/O register space ($0000–$00FF). The 8-channel ADC operates with 10 µs conversion time at 4 MHz bus clock and supports single-ended inputs referenced to V_DD/V_SS.

Key Specifications

Pinout & Package

MC68HC908QY2CDW is housed in a 16-pin SOIC-W (Small Outline Integrated Circuit – Wide) package per JEDEC MS-013AC, with 1.27 mm pitch and 7.5 mm body width. Thermal resistance θ_JA = 110°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC68HC908QY2CDW, the QT2 variant removes analog and keyboard peripherals to lower cost for digital-only tasks, while the RS08KA2 offers upgraded ADC and voltage range at the expense of legacy HCS08 software compatibility.

Availability

MC68HC908QY2CDW is available at Aetrix Electronics and suitable for appliance control panels, industrial sensor nodes, and smart power outlets requiring stable component supply and long-term manufacturability.

Supply support for MC68HC908QY2CDW 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

NXP Semiconductors is a global semiconductor leader delivering secure, connected, and intelligent solutions for automotive, industrial, IoT, and mobile applications.

The MC68HC908QY/QT family was designed for cost-optimized 8-bit embedded control in resource-constrained environments, emphasizing low power, integrated peripherals, and field-programmable FLASH for rapid iteration.

FAQ

What is the maximum bus clock frequency supported by the MC68HC908QY2CDW?

The MC68HC908QY2CDW supports a maximum bus clock frequency of 8 MHz. This is achieved using the internal oscillator (trimmed to 4 MHz) with BUSCLKX4 output enabled, or by connecting an external 8 MHz crystal to the OSC1/OSC2 pins and configuring the oscillator module for crystal mode. The CPU executes instructions at bus clock speed, enabling up to 2 million instructions per second (MIPS) in typical operation.

Does the MC68HC908QY2CDW support in-circuit programming after soldering?

Yes, the MC68HC908QY2CDW supports in-circuit programming via its single-wire background debug mode (BDM) interface on the TEST/BKGD pin. Using a standard BDM pod or compatible debugger, full FLASH erase, program, and verify operations can be performed without removing the device from the PCB. No external high-voltage programming signals are required.

How many I/O pins does the MC68HC908QY2CDW provide, and which support wake-up from STOP mode?

The MC68HC908QY2CDW provides 12 usable I/O pins: PTA0–PTA3 (4 pins), PTA5–PTA7 (3 pins), and PTB0–PTB3 (4 pins). Of these, PTA0–PTA3 and PTB0 are configured as keyboard interrupt (KBI) or external interrupt (IRQ) inputs and can generate wake-up events from STOP or WAIT mode. All other pins remain inactive during STOP mode unless explicitly enabled for low-leakage operation.

What is the purpose of the OSCTRIM register in the MC68HC908QY2CDW?

The OSCTRIM register (located at memory address $FFC0) stores a factory-calibrated or user-defined 8-bit value that adjusts the internal RC oscillator's frequency. Writing to this register modifies the oscillator's bias current, allowing compensation for process, voltage, and temperature variations. When trimmed, the internal oscillator achieves ±2% accuracy over the full operating range, eliminating need for external crystal in cost-sensitive applications.

Can the MC68HC908QY2CDW operate from a 3.3 V supply, and what ADC reference is used?

Yes, the MC68HC908QY2CDW operates across 2.7–5.5 V, making 3.3 V fully supported. Its 8-bit ADC uses V_DD as the default reference voltage, so at 3.3 V supply, full-scale conversion corresponds to 3.3 V and 1 LSB = 12.9 mV. No separate AV_DD or reference pin is provided - the ADC shares the main supply rail, simplifying layout but tying resolution directly to supply stability.