NXP Semiconductors MC908LK24CPBE

Overview

MC908LK24CPBE 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), infrared serial interface (IRSCI), SPI, I²C, 10-bit ADC, and PWM-capable TIM module. Designed for low-power embedded instrumentation and portable consumer devices with display requirements.

For engineers reviewing the MC908LK24CPBE datasheet, MC908LK24CPBE pinout, MC908LK24CPBE application, or MC908LK24CPBE equivalent, key selection criteria include its 24 KB Flash/1 KB RAM memory configuration, 32-segment LCD driver capability, RTC with calendar/alarm functions, IRSCI compliance with IrDA physical layer, and 56-pin LQFP package with VDDA/VSSA analog supply separation.

Technical Context

The MC908LK24CPBE implements the HCS08 CPU core with 16-bit address space, 8-bit data bus, and enhanced BDM debug interface. Its Clock Generator Module (CGM) integrates a PLL with programmable multipliers (×1 to ×32) and reference dividers, enabling precise bus clock generation from internal RC or external crystal sources.

System integration includes a System Integration Module (SIM) managing reset sequencing, interrupt prioritization across 16 vectors, and low-power modes (Wait/Stop). The Real Time Clock supports time/calendar tracking, alarm interrupts, and ±1 ppm calibration via RTCCOMR/RTCCDAT registers - all operating independently in Stop mode with VBAT backup support.

Key Specifications

Pinout & Package

MC908LK24CPBE is housed in a 56-pin LQFP package with exposed thermal pad. Pin assignments follow standard HCS08 port mapping: Port A (PTA0–PTA7), Port B (PTB0–PTB7), Port C (PTC0–PTC7), Port D (PTD0–PTD7), Port E (PTE0–PTE7), and Port F (PTF0–PTF7), plus dedicated oscillator (OSC1/OSC2), reset (RST), IRQ, CGMXFC, and LCD-specific pins (VLCD, BP0–BP2, FP0–FP32).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC908LK24CPBE, MC908LK24CFUE offers identical functionality in a larger package with extended temperature range, while S9KEAZN32ACLC trades LCD integration for ARM-based performance and modern interfaces - making the former a drop-in replacement for footprint-constrained industrial designs, and the latter suitable for next-generation platforms requiring protocol expansion.

Availability

MC908LK24CPBE is available at Aetrix Electronics and suitable for portable medical instrumentation, industrial panel meters, smart home thermostats, and handheld test equipment requiring stable component supply, long-term lifecycle support, and RoHS-compliant manufacturing.

Supply support for MC908LK24CPBE 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 specializing in secure connectivity solutions for automotive, industrial, and IoT applications, with roots in Freescale's microcontroller heritage.

The MC908LK24CPBE belongs to the HCS08 family, designed specifically for cost-sensitive, low-power embedded systems requiring integrated LCD, RTC, and infrared communication - targeting portable instrumentation and human-interface devices.

FAQ

What is the maximum bus clock frequency supported by the MC908LK24CPBE?

The MC908LK24CPBE supports a maximum bus clock frequency of 20 MHz. This is achieved using the integrated Clock Generator Module (CGM) with PLL multiplier settings and external crystal or internal RC oscillator sources. The actual achievable frequency depends on the selected oscillator mode and CGM configuration registers (e.g., PLLCTL, PLLBDIV), and must comply with the electrical specifications defined in Section 24 of the datasheet under VDD = 5.0 V conditions.

Does the MC908LK24CPBE support true EEPROM functionality?

The MC908LK24CPBE does not include dedicated EEPROM memory but supports EEPROM emulation using on-chip Flash memory. Through firmware routines such as EE_WRITE and EE_READ (resident in Monitor ROM), users can implement wear-leveling and page management to achieve reliable non-volatile data storage. This approach provides ~100,000 write/erase cycles per Flash sector when properly managed, matching typical EEPROM endurance requirements for calibration data or configuration storage.

How many LCD segments can the MC908LK24CPBE drive, and what multiplexing configurations are supported?

The MC908LK24CPBE drives up to 32 LCD segments using its integrated LCD controller. It supports 3- or 4-backplane multiplexing (3×9 or 4×8 configurations), selectable via LCDCTL register bits. The VLCD pin provides internally generated bias voltage, and contrast is adjusted through software-controlled resistor ladder settings. All segment outputs are mapped to Port F pins (PTF0–PTF7) and dedicated frontplane/backplane terminals (FP0–FP32, BP0–BP2).

Can the MC908LK24CPBE operate from a single 3.3 V supply?

No - the MC908LK24CPBE is specified for operation at 4.5 V to 5.5 V nominal supply (VDD). While some peripherals like the RTC may function down to 2.7 V in Stop mode with VBAT, the core logic, Flash programming, and LCD driver require the full 5 V range. Operating below 4.5 V risks undefined behavior, failed Flash writes, or incomplete LCD bias generation. For 3.3 V systems, level-shifting or a compatible 5 V supply rail is mandatory.

What debug interface does the MC908LK24CPBE use, and is it compatible with modern tools?

The MC908LK24CPBE uses the Background Debug Mode (BDM) interface, implemented via a single-wire SWD-compatible pin (BKGD). It is supported by legacy Freescale BDM pods and modern NXP-compatible debuggers including the S32DS IDE with PE Micro Cyclone MAX or Segger J-Link (with appropriate BDM firmware). No JTAG interface is present; debugging requires BDM-aware toolchains and the MON ROM bootloader for flash programming and runtime inspection.