NXP Semiconductors MC68HC908QY4CDTE

Overview

MC68HC908QY4CDTE 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 (1–8 MHz), low-voltage inhibit (LVI), computer operating properly (COP) watchdog, and keyboard interrupt (KBI) for touch-key applications. Designed for cost-sensitive embedded control in appliance user interfaces and industrial sensors.

For engineers reviewing the MC68HC908QY4CDTE datasheet, MC68HC908QY4CDTE pinout, MC68HC908QY4CDTE application, or MC68HC908QY4CDTE equivalent, key selection criteria include its 16-pin SOIC package, 5 V operation, internal oscillator trim capability, KBI wake-on-keypress support, and FLASH-based field programmability without external high-voltage programming.

Technical Context

The MC68HC908QY4CDTE implements the HCS08 CPU core with 16-bit address bus, supporting up to 64 KB memory space. Its oscillator module allows dynamic switching between internal RC and external crystal sources, with OSCTRIM register enabling factory or field calibration of internal clock accuracy to ±2% over temperature and voltage.

Peripheral integration includes a 16-bit Timer Interface Module (TIM) with input capture/output compare, an Auto Wakeup Module (AWU) providing programmable sleep intervals down to 16 ms, and a Low-Voltage Inhibit (LVI) circuit with selectable trip points (4.25 V or 3.7 V) for brownout protection and reset generation.

Key Specifications

Pinout & Package

MC68HC908QY4CDTE is housed in a 16-pin SOIC package (case 751BD-02), 7.5 mm × 10.3 mm body, 1.27 mm pitch, with standard gull-wing leads. Thermal resistance θ_JA = 110°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC9RS08KA2CSCR and MC908QY4CDTE, the MC68HC908QY4CDTE offers verified KBI support and full backward compatibility with QY-series toolchains, making it optimal for legacy-compatible keypad and appliance control upgrades where interrupt-driven wake and 5 V robustness are essential.

Availability

MC68HC908QY4CDTE is available at Aetrix Electronics and suitable for home appliance control panels, industrial sensor nodes, and point-of-sale keypads requiring stable component supply and long-lifecycle support.

Supply support for MC68HC908QY4CDTE 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 focused on secure connectivity solutions for automotive, industrial, and IoT applications.

The MC68HC908QY4CDTE belongs to the HCS08 microcontroller family, designed specifically for cost-effective, low-power embedded control in appliances, industrial controls, and human-interface devices where Flash programmability and integrated peripherals reduce system complexity.

FAQ

What is the maximum operating frequency of the MC68HC908QY4CDTE?

The MC68HC908QY4CDTE operates with a maximum bus clock frequency of 8 MHz, derived from its internal RC oscillator or external crystal source. When using the internal oscillator, factory-trimmed accuracy is ±2% over temperature and voltage; trimming via OSCTRIM register allows field calibration to maintain timing integrity in variable environments. The MC68HC908QY4CDTE does not support PLL multiplication - its core speed equals the bus clock.

Does the MC68HC908QY4CDTE support in-circuit debugging?

Yes, the MC68HC908QY4CDTE supports background debug mode (BDM) via a single-wire interface using the BKGD pin. This enables non-intrusive program download, breakpoint setting, and real-time register inspection without requiring dedicated debug headers or JTAG. The MC68HC908QY4CDTE's BDM implementation is compatible with standard Freescale/NXP BDM debuggers and CodeWarrior development tools.

How many I/O pins does the MC68HC908QY4CDTE provide?

The MC68HC908QY4CDTE provides 12 general-purpose I/O pins: Port A (PTA0–PTA7) offers 8 pins, and Port B (PTB0–PTB3) adds 4 more. All pins are individually configurable as input or output via Data Direction Registers (DDRA/DDRB). PTA0–PTA3 double as Keyboard Interrupt inputs, and PTB0 serves as the external IRQ pin. The MC68HC908QY4CDTE reserves no pins for fixed alternate functions - all I/O is software-mapped.

What is the purpose of the OSCTRIM register in the MC68HC908QY4CDTE?

The OSCTRIM register (address $FFC0) in the MC68HC908QY4CDTE stores a factory-programmed 8-bit value used to calibrate the internal RC oscillator frequency. Writing to OSCTRIM adjusts the oscillator's RC network bias, enabling compensation for process and temperature variations. This allows the MC68HC908QY4CDTE to achieve ±2% accuracy across –40°C to +85°C, critical for UART communication and real-time scheduling where precise timing is required without external crystals.

Can the MC68HC908QY4CDTE operate from a 3.3 V supply?

No, the MC68HC908QY4CDTE is specified only for 4.5 V to 5.5 V operation per its electrical characteristics table (Section 16.1). It lacks 3.3 V logic-level compatibility or internal voltage regulation. Attempting 3.3 V operation will result in undefined behavior, failed FLASH programming, or inability to meet timing specifications. For 3.3 V systems, designers should select modern NXP S08 or S32K devices - the MC68HC908QY4CDTE requires strict adherence to its 5 V supply range.