NXP Semiconductors MC908LJ24CPBE

Overview

MC908LJ24CPBE 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 (MMIIC), 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 MC908LJ24CPBE datasheet, MC908LJ24CPBE pinout, MC908LJ24CPBE application, or MC908LJ24CPBE 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 support for both internal RC and external crystal oscillator modes.

Technical Context

The MC908LJ24CPBE implements the HCS08 CPU core with 16-bit address space, supporting wait/stop low-power modes and COP watchdog. Its Clock Generator Module (CGM) integrates a PLL for frequency multiplication of the reference clock, enabling flexible bus speed configuration up to 8 MHz.

The System Integration Module (SIM) manages reset sources-including POR, LVI, COP, and illegal opcode-and coordinates interrupt vectors across 16 priority levels. The IRSCI module combines infrared encoder/decoder logic with standard SCI framing, allowing bidirectional IrDA-compliant communication without external transceivers.

Key Specifications

Pinout & Package

MC908LJ24CPBE is housed in a 64-pin QFP (Quad Flat Package) with 0.5 mm pitch, RoHS-compliant lead-free finish, and thermal pad for enhanced heat dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC908LJ12CPBE, the MC908LJ24CPBE provides double Flash and RAM for richer UI logic and data logging; versus MC908LK24CPBE, it omits CAN but retains full LCD, RTC, and IRSCI capabilities at lower unit cost and BOM complexity.

Availability

MC908LJ24CPBE is available at Aetrix Electronics and suitable for portable medical instrumentation, industrial HMI panels, smart energy meters, and home appliance control requiring stable component supply and long-term lifecycle support.

Supply support for MC908LJ24CPBE 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 company specializing in secure connectivity solutions for automotive, industrial, and IoT applications.

The MC908LJ24CPBE belongs to the HCS08 family, designed specifically for cost-sensitive, low-power embedded control applications requiring integrated human-machine interface peripherals including LCD drivers, RTC, and infrared communication.

FAQ

What is the maximum operating frequency of the MC908LJ24CPBE?

The MC908LJ24CPBE supports a maximum bus frequency of 8 MHz, achieved via its internal PLL that multiplies the reference clock (e.g., 32.768 kHz crystal or internal RC oscillator). This frequency governs instruction execution speed, peripheral timing, and LCD refresh rate. The device maintains full functionality across its specified temperature range (–40°C to +85°C) at this speed.

Does the MC908LJ24CPBE support in-circuit debugging?

Yes, the MC908LJ24CPBE includes a dedicated Break Module (BRK) and Monitor ROM (MON) that enable hardware-assisted in-circuit debugging. Using the BRK pin and serial interface, developers can perform single-stepping, register inspection, and flash programming without requiring external JTAG adapters. The MON provides secure bootloader and flash programming routines accessible via UART or IRSCI.

Can the MC908LJ24CPBE drive a 4×32 segment LCD directly?

Yes, the MC908LJ24CPBE integrates a fully configurable LCD driver capable of driving up to 4 commons and 32 segments in static, 2-mux, 3-mux, or 4-mux configurations. It provides VLCD bias generation, software-controllable contrast, and automatic frame inversion to reduce flicker-eliminating the need for external LCD controllers in most HMI designs.

What low-power modes does the MC908LJ24CPBE support?

The MC908LJ24CPBE supports Wait and Stop modes. In Wait mode, the CPU halts while peripherals (RTC, KBI, IRSCI) remain active; in Stop mode, nearly all clocks are disabled, reducing current draw to less than 1 µA. Both modes retain RAM contents and support wake-up via IRQ, KBI, RTC alarm, or IRSCI activity-ideal for battery-operated devices requiring extended sleep periods.

Is the MC908LJ24CPBE pin-compatible with other HCS08 family members?

No, the MC908LJ24CPBE is not universally pin-compatible across the HCS08 family. While it shares the 64-pin QFP package with MC908LK24CPBE, pin functions differ-for example, LK24 includes CAN_TX/RX pins not present on LJ24. Always verify pin assignments using Section 1.5 ("Pin Assignments") and Section 1.6 ("Pin Functions") of the MC68HC908LJ24 datasheet before board reuse.