NXP Semiconductors MC68HC908QY4CDW

Overview

MC68HC908QY4CDW from NXP (formerly Freescale) is an 8-bit HCS08-core microcontroller with 4 KB on-chip FLASH, 192 B RAM, and integrated 8-channel 8-bit ADC. It features internal RC oscillator (trimmed to ±2% at 3.58 MHz), low-voltage inhibit (LVI), computer operating properly (COP) watchdog, and keyboard interrupt (KBI) for touch-key sensing. Used in cost-sensitive industrial control panels and appliance user interfaces.

For engineers reviewing the MC68HC908QY4CDW datasheet, MC68HC908QY4CDW pinout, MC68HC908QY4CDW application, or MC68HC908QY4CDW equivalent, key selection criteria include its 16-pin SOIC-W package, 3.3–5.5 V operation, 1.25 µs instruction cycle at 8 MHz bus clock, KBI wake-on-key capability, and FLASH endurance of 10,000 erase/write cycles.

Technical Context

The MC68HC908QY4CDW implements the HCS08 CPU core with 16-bit address space, supporting WAIT/STOP low-power modes and a configurable COP timeout ranging from 2.1 ms to 1.4 s. 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 4 KB FLASH (organized as 64 × 64-byte pages), 192 B RAM, and 32 B EEPROM-equivalent data storage via FLASH emulation. Peripheral integration includes 8-bit TIM with input capture/output compare, 8-channel ADC with software-triggered conversion, and dual I/O ports (Port A: 8-bit bidirectional; Port B: 4-bit bidirectional) with programmable pull-ups.

Key Specifications

Pinout & Package

MC68HC908QY4CDW is housed in a 16-pin SOIC-W (Small Outline Integrated Circuit, Wide-body) package per JEDEC MS-013AC, with 7.5 mm body width and 1.27 mm lead pitch. Thermal resistance θ_JA = 100°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC9RS08KA2CSC and STM8S003F3P6, the MC68HC908QY4CDW offers unique KBI hardware acceleration and factory-trimmed RC oscillator accuracy ideal for cost-constrained, touch-interface designs where pin count and BOM simplicity are critical.

Availability

MC68HC908QY4CDW is available at Aetrix Electronics and suitable for industrial control panels, home appliance user interfaces, and smart sensor nodes requiring stable component supply across extended production lifecycles.

Supply support for MC68HC908QY4CDW 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 company formed from the spin-off of Philips' semiconductor division, specializing in secure connectivity solutions for automotive, industrial, and IoT markets.

The MC68HC908QY4CDW belongs to the legacy HCS08 microcontroller family designed for cost-sensitive, low-pin-count embedded control applications demanding robustness, low power, and minimal external components.

FAQ

What is the maximum bus clock frequency supported by the MC68HC908QY4CDW?

The MC68HC908QY4CDW supports a maximum bus clock frequency of 8 MHz, achieved using the internal oscillator (trimmed to 3.58 MHz base) with BUSCLKX4 prescaler enabled or external crystal up to 8 MHz. At 8 MHz bus clock, instruction execution time is 125 ns per cycle, enabling real-time response in control loops and interrupt service routines. The MC68HC908QY4CDW's timing specifications are validated across the full 3.3–5.5 V supply range and –40°C to +85°C ambient temperature.

Does the MC68HC908QY4CDW support in-system programming (ISP)?

Yes, the MC68HC908QY4CDW supports in-system programming via its single-wire background debug mode (BDM) using the RESET pin. No external programming hardware is required beyond a BDM interface adapter. FLASH memory can be reprogrammed while soldered on the target board, and the MC68HC908QY4CDW retains full functionality during programming - including interrupt handling and peripheral operation - provided the BDM command sequence is correctly implemented per Freescale AN2295.

How does the Keyboard Interrupt Module (KBI) function on the MC68HC908QY4CDW?

The KBI on the MC68HC908QY4CDW monitors PTB0–PTB2 for keypress events using hardware-driven edge detection and optional debounce filtering. It generates an interrupt and automatically wakes the MCU from WAIT or STOP mode. The MC68HC908QY4CDW's KBI operates independently of CPU execution, allowing immediate response to user input even during low-power states - critical for battery-operated interfaces where latency and power efficiency are tightly coupled.

What is the FLASH endurance and data retention specification for the MC68HC908QY4CDW?

The MC68HC908QY4CDW guarantees 10,000 erase/write cycles per FLASH block and 10-year data retention at +85°C ambient temperature. Each 64-byte page can be erased individually, and protection bits (FLBPR) prevent accidental writes to critical bootloader or configuration sectors. The MC68HC908QY4CDW's FLASH controller includes built-in error detection during program/erase operations, and all timing parameters comply with JEDEC JESD22-A117 reliability standards.

Can the MC68HC908QY4CDW operate from a 3.3 V supply without level-shifting?

Yes, the MC68HC908QY4CDW is fully specified for 3.3 V operation across its entire temperature range (–40°C to +85°C), with all I/O pins tolerant to 5 V inputs when configured as inputs. Its internal regulator and oscillator remain stable at 3.3 V, and the MC68HC908QY4CDW maintains full peripheral functionality - including ADC accuracy, KBI sensitivity, and COP timing - without external level shifters or voltage translators.