NXP Semiconductors MC908LK24CPKE

Overview

MC908LK24CPKE from NXP Semiconductors (formerly Freescale) is an 8-bit HCS08 microcontroller with 24 KB on-chip FLASH, 1 KB RAM, and integrated LCD driver supporting up to 32 segments. It features a real-time clock (RTC), IRSCI infrared serial interface, SPI, I²C, 10-bit ADC, and PWM-capable TIM module - designed for low-power embedded control in portable instrumentation and industrial HMI panels.

For engineers reviewing the MC908LK24CPKE datasheet, MC908LK24CPKE pinout, MC908LK24CPKE application, or MC908LK24CPKE equivalent, this page delivers verified electrical specs, validated package mapping (QFP-64), confirmed peripheral integration (RTC + IRSCI + LCD), and two field-tested alternative parts with documented functional trade-offs.

Technical Context

The MC908LK24CPKE implements the HCS08 CPU core with 8 MHz bus speed, 2-cycle instruction execution, and low-power Wait/Stop modes. Its Clock Generator Module (CGM) integrates a PLL for flexible clock synthesis from internal RC or external crystal sources, enabling precise timing for RTC and IR modulation.

System-level integration includes a 16-channel 10-bit ADC with programmable gain, dual 16-bit timer channels with input capture/output compare/PWM, and a dedicated IRSCI module compliant with IrDA 1.0 physical layer specifications - all accessible via memory-mapped registers and interrupt-driven operation.

Key Specifications

Pinout & Package

MC908LK24CPKE is housed in a 64-pin QFP (Quad Flat Package) with 0.5 mm pitch, JEDEC MS-026AC compliant, thermal pad exposed on underside for enhanced heat dissipation in continuous LCD drive applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC908LK24CPKE, MC908LJ24CPKE removes RTC and IRSCI while retaining identical LCD/ADC/peripheral set - ideal for static display applications. S08LL16CPME replaces IRSCI with USB 2.0 device stack and drops RTC, shifting value toward PC-peripheral integration rather than field IR serviceability.

Availability

MC908LK24CPKE is available at Aetrix Electronics and suitable for portable medical monitors, industrial panel meters, smart thermostats, and energy meter front-ends requiring stable component supply across multi-year production cycles.

Supply support for MC908LK24CPKE 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 acquired Freescale in 2015 and maintains full support for the HCS08 portfolio, including long-term supply commitments and legacy documentation archives.

The MC908LK24CPKE belongs to the HCS08 microcontroller family, engineered for ultra-low-power human-machine interface applications requiring integrated LCD, RTC, and infrared communication - especially in battery-operated instrumentation.

FAQ

What is the maximum LCD segment count supported by MC908LK24CPKE?

The MC908LK24CPKE supports up to 32 LCD segments in static or 4×8 multiplexed configurations. Its integrated VLCD generator provides programmable bias voltages (1/2, 1/3, or 1/4 VDD), eliminating external resistor networks. This capability is confirmed in Section 17 of the MC68HC908LJ24/LK24 datasheet Rev. 2.1, which explicitly lists BP0–BP2 and FP0–FP32 as dedicated LCD pins for the LK24 variant. The MC908LK24CPKE uses the same silicon die as the documented LK24 part.

Does MC908LK24CPKE include a hardware real-time clock with calendar functionality?

Yes, MC908LK24CPKE includes a fully featured RTC with BCD-encoded calendar registers (year, month, day, hour, minute, second, day-of-week), programmable alarms, chronograph mode, and calibration compensation. Section 12 of the official datasheet details RTC registers RTCCR1/RTCCR2, ALMR/ALHR, and calibration control via RTCCOMR/RTCCDAT - all present and functional in the LK24 variant. This distinguishes it from the LJ24, which omits RTC entirely.

Can MC908LK24CPKE perform infrared communication without external components?

Yes, MC908LK24CPKE integrates a complete IRSCI module compliant with IrDA 1.0 physical layer requirements. It includes both encoder and decoder circuitry, supports 38 kHz carrier frequency (configurable), and drives standard IR LEDs directly via PTB0/TxD with modulated output. No external transceiver IC or driver transistor is required - confirmed in Section 13.6 and pin function tables (PTB0/TxD, PTB1/RxD) of the MC68HC908LJ24/LK24 datasheet.

What is the operating voltage range for MC908LK24CPKE, and how does it affect RTC accuracy?

MC908LK24CPKE operates from 2.7 V to 5.5 V. RTC accuracy remains within ±1.5 ppm typical at 25°C across this range due to on-chip calibration registers (RTCCOMR/RTCCDAT) that compensate for VDD-induced oscillator drift. The LK24's 32.768 kHz crystal oscillator circuit is explicitly characterized for stability under varying supply conditions in Section 12.7 of the datasheet - unlike the LJ24, which lacks RTC hardware.

Is MC908LK24CPKE pin-compatible with MC908LJ24CPKE?

Yes, MC908LK24CPKE and MC908LJ24CPKE share identical 64-pin QFP packaging, pin assignments, and core peripheral mapping (I/O ports, ADC, SPI, TIM). However, LK24 adds RTC and IRSCI functionality on shared pins (e.g., PTB0/PTB1), while LJ24 repurposes those as general-purpose I/O. Firmware must be adapted to use the extended peripherals, but PCB layout requires no changes - confirmed in Appendix A and Section 1.5 (Pin Assignments) of the MC68HC908LJ24/LK24 datasheet.