NXP Semiconductors MC908LJ24CFUER

Overview

MC908LJ24CFUER 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 MC908LJ24CFUER datasheet, MC908LJ24CFUER pinout, MC908LJ24CFUER application, or MC908LJ24CFUER equivalent, key selection criteria include its 24 KB FLASH endurance (100k erase/write cycles), 1.8–5.5 V operating range, RTC calendar/alarm functions, and 64-pin QFP package with dedicated LCD bias (VLCD) and analog reference (VREFH/VREFL) pins.

Technical Context

The MC908LJ24CFUER implements the HCS08 CPU core with 16-bit address space, 8-level hardware stack, and COP watchdog. Its Clock Generator Module (CGM) supports internal RC oscillator (1–8 MHz) and external crystal (up to 8 MHz), with PLL-based frequency multiplication for system clock scaling.

System integration includes a System Integration Module (SIM) managing reset sources (POR, LVI, COP), interrupt prioritization across 27 vectors, and low-power modes (Wait/Stop). The IRSCI module integrates both infrared encoder/decoder and standard SCI functionality on shared PTB0/TxD and PTB1/RxD pins.

Key Specifications

Pinout & Package

MC908LJ24CFUER is housed in a 64-pin Quad Flat Package (QFP) with 0.5 mm lead pitch, designed for high-density PCB layouts and thermal reliability in industrial environments. Pin assignments follow standard HCS08 I/O port mapping with dedicated functional groups for LCD, RTC backup, and analog subsystems.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC908LJ24CFUER, the MC908LJ12CFUER offers identical architecture and peripherals at reduced memory cost, while the S9KEAZ128AMLH provides scalable 32-bit performance but requires redesign of IR and LCD interfaces - making MC908LJ24CFUER optimal for cost-sensitive, LCD+IR legacy upgrades.

Availability

MC908LJ24CFUER is available at Aetrix Electronics and suitable for portable medical devices, industrial HMI panels, energy submeters, and smart appliance user interfaces requiring stable component supply and long-term lifecycle support.

Supply support for MC908LJ24CFUER 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 MC908LJ24CFUER belongs to the legacy HCS08 microcontroller family, engineered for ultra-low-power, cost-sensitive embedded control with integrated analog and human-interface peripherals - especially suited for battery-operated instrumentation and industrial displays.

FAQ

What is the maximum operating frequency of the MC908LJ24CFUER?

The MC908LJ24CFUER supports a maximum system clock frequency of 8 MHz when using an external crystal oscillator. Its internal CGM allows PLL-based multiplication, but the core execution speed remains bounded by the 8 MHz bus clock specification. This frequency ensures deterministic timing for RTC, ADC sampling, and PWM generation while maintaining low EMI in compact PCB layouts.

Does the MC908LJ24CFUER support in-circuit debugging?

Yes, the MC908LJ24CFUER 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 halting peripheral operation - critical for validating RTC alarm behavior or IRSCI signal timing during development.

How does the IRSCI module on the MC908LJ24CFUER differ from a standard UART?

The IRSCI module on the MC908LJ24CFUER integrates both standard UART (SCI) and infrared protocol handling (NEC, RC-5) in one peripheral. Unlike a basic UART, it includes hardware modulation/demodulation circuitry, carrier frequency tuning (30–56 kHz), and pulse-width decoding logic - eliminating external IR receiver ICs and reducing bill-of-materials for remote-control-enabled devices.

Can the MC908LJ24CFUER retain RTC data during power loss?

Yes, the MC908LJ24CFUER retains RTC calendar and alarm registers during power loss if VDDA (analog supply) remains active above 1.8 V, typically via a small backup capacitor or coin cell. The RTC domain operates independently of the main VDD domain, allowing timekeeping continuity across main power interruptions - essential for energy metering and maintenance scheduling.

What LCD configuration options does the MC908LJ24CFUER support?

The MC908LJ24CFUER supports static and multiplexed LCD configurations up to 32 segments × 4 commons. It generates VLCD bias internally and supports software-selectable duty cycle (1/2, 1/3, or 1/4) and bias voltage level (VLCD = 2.0×VDD to 3.5×VDD). This flexibility accommodates common character displays and custom segment layouts without external charge pumps.