NXP Semiconductors MC908LJ24CFUE

Overview

MC908LJ24CFUE from NXP (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-compatible MMIIC, 10-bit ADC, and PWM-capable TIM module. Designed for low-power portable instrumentation and industrial control panels with segmented displays.

For engineers reviewing the MC908LJ24CFUE datasheet, MC908LJ24CFUE pinout, MC908LJ24CFUE application, or MC908LJ24CFUE equivalent, key selection criteria include its 32-segment LCD drive capability, RTC with calendar/alarm functions, IRSCI compliance with IrDA 1.0 physical layer, and 5 V-tolerant I/O in 64-pin QFP package - all critical for battery-powered metering and human-interface applications.

Technical Context

The MC908LJ24CFUE implements the HCS08 CPU core with enhanced BDM debug support and executes instructions at up to 20 MHz bus frequency. Its Clock Generator Module includes a PLL with programmable multiplier (×1 to ×32) and reference divider, enabling precise clock synthesis from internal RC or external crystal sources.

System integration includes a System Integration Module (SIM) managing reset sources (POR, LVI, COP, illegal opcode), low-power modes (Wait/Stop), and interrupt prioritization across 16 vectors. The Monitor ROM provides in-system programming via IRSCI or SCI without external hardware programmer.

Key Specifications

Pinout & Package

MC908LJ24CFUE is housed in a 64-pin Quad Flat Package (QFP) with 0.5 mm lead pitch, designed for surface-mount assembly and thermal reliability in industrial environments. Pin assignments follow standard HCS08 port mapping with dedicated LCD segment/backplane pins, analog references, and IRSCI I/O.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC908LJ12CFUE, the MC908LJ24CFUE offers double Flash and RAM for richer UI logic and data logging; versus S9KEAZ128AMLH, it delivers lower system-level BOM cost and simpler design for LCD-centric, cost-sensitive embedded instruments.

Availability

MC908LJ24CFUE is available at Aetrix Electronics and suitable for smart metering, industrial HMIs, portable medical devices, and building automation thermostats requiring stable component supply and long-lifecycle support.

Supply support for MC908LJ24CFUE 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 markets.

The MC908LJ24CFUE belongs to the legacy HCS08 microcontroller family, engineered for ultra-low-power, cost-sensitive embedded systems with integrated human-interface peripherals - especially LCD, RTC, and IR communication.

FAQ

What is the maximum operating frequency of the MC908LJ24CFUE?

The MC908LJ24CFUE supports a maximum bus frequency of 20 MHz, achieved via its Clock Generator Module's PLL with programmable multiplier and reference divider. This frequency is sustained across the full 2.7–5.5 V supply range and commercial temperature grade (–40°C to +85°C). The actual core instruction throughput depends on the HCS08 architecture's two-cycle-per-instruction execution model.

Does the MC908LJ24CFUE support in-system programming without external hardware?

Yes, the MC908LJ24CFUE includes a Monitor ROM (MON) that enables in-system programming via its IRSCI or SCI interface using standard serial commands. No external programmer is required - firmware updates can be performed over infrared or UART using the PRGRNGE, ERARNGE, and LDRNGE ROM-resident routines documented in Section 10 of the datasheet.

How many LCD segments can the MC908LJ24CFUE drive, and what mux configurations are supported?

The MC908LJ24CFUE drives up to 32 segments with 3 backplanes, supporting static, 2-mux, 3-mux, and 4-mux LCD configurations. Segment and backplane assignments are fixed per pin (e.g., FP0–FP32, BP0–BP2), and mux ratio is configured via the LCDCTL register. VLCD bias voltage is generated internally and adjustable in 16 steps for optimal contrast across temperature and supply variations.

What RTC capabilities does the MC908LJ24CFUE provide beyond basic timekeeping?

The MC908LJ24CFUE RTC implements a full calendar (year/month/day/hour/minute/second), alarm interrupt with minute/hour match, chronograph with 1/100 s resolution, and programmable calibration register for ±1 ppm adjustment. It maintains time in Stop mode using the 32.768 kHz crystal, and supports automatic leap-year correction and day-of-week calculation in firmware via register reads.

Is the MC908LJ24CFUE pin-compatible with other members of the LJ/LK24 family?

Yes, the MC908LJ24CFUE shares identical 64-pin QFP packaging and pinout with MC68HC908LK24 and MC908LJ12CFUE. Peripheral mappings, I/O register addresses, and reset behavior are functionally aligned, enabling direct PCB reuse when migrating between 12 KB and 24 KB Flash variants within the same temperature and voltage grade.