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NXP Semiconductors MC68HC908LJ24CPB
- Part No.:
- MC68HC908LJ24CPB
- Manufacturer:
- NXP Semiconductors
- Category:
- Microcontrollers
- Package:
- 64-LQFP
- Datasheet:
-
MC68HC908LJ24CPB.pdf
- Description:
- IC MCU 8BIT 24KB FLASH 64LQFP
- Quantity:
- Payment:
- Shipping:
Inventory:3,287
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Product details
Overview
MC68HC908LJ24CPB from Freescale Semiconductor is an 8-bit HCS08-core microcontroller with 24 KB on-chip FLASH, 512 B RAM, integrated RTC, LCD driver (up to 32 segments), IRSCI, SPI, I²C, and 10-bit ADC. It operates at up to 8 MHz bus frequency and supports low-power stop/wait modes for battery-powered instrumentation and industrial control.
For engineers reviewing the MC68HC908LJ24CPB datasheet, MC68HC908LJ24CPB pinout, MC68HC908LJ24CPB application, or MC68HC908LJ24CPB equivalent, key selection criteria include its integrated real-time clock with calendar/alarm functions, 32-segment LCD bias generation, infrared serial interface compliance with IrDA 1.0 physical layer, and FLASH block protection for secure firmware updates.
Technical Context
The MC68HC908LJ24CPB implements the HCS08 CPU core with enhanced addressing modes and a 16-level hardware stack. Its Clock Generator Module includes a PLL with programmable multiplier (×1 to ×32) and reference divider, enabling precise bus clock synthesis from internal RC or external crystal sources.
System integration includes a full-featured Real Time Clock with independent 32.768 kHz oscillator input, calibration register (±127 ppm adjustment), and alarm/chronograph registers. The IRSCI module supports both standard UART framing and infrared carrier modulation (38 kHz) with configurable pulse width and duty cycle.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| CPU Core | HCS08 8-bit CISC core with 16-level stack and indexed addressing |
| FLASH Memory | 24 KB on-chip SuperFlash® with block erase, mass erase, and 100K-cycle endurance |
| RAM | 512 bytes static RAM with retention in stop mode |
| Bus Frequency | Up to 8 MHz - determines maximum instruction throughput and peripheral timing margins |
| RTC Accuracy | ±1.5 ppm typical with 32.768 kHz crystal; calibrated via RTCCOMR register |
| LCD Driver | Supports 4×8 or 3×9 multiplexed displays (32 segments total) with VLCD bias generation |
| ADC | 10-bit successive approximation ADC with 8-channel analog input and VREFH/VREFL references |
Pinout & Package
MC68HC908LJ24CPB is housed in a 64-pin LQFP package (10 mm × 10 mm, 0.5 mm pitch) with exposed thermal pad. Pin assignments are defined per Section 1.5 (Pin Assignments) and Section 1.6 (Pin Functions) of the Rev. 2.1 datasheet.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD, VSS | Power supply and ground | Digital core power (VDD) and return (VSS); separate VDDA/VSSA for analog/RTC sections |
| OSC1, OSC2 | Crystal oscillator terminals | Connects to 32.768 kHz crystal for RTC or higher-frequency crystal (1–8 MHz) for main system clock |
| RST | Active-low reset input | Asynchronous external reset; also accepts POR/LVI/COP-generated internal reset signals |
| PTB0/TxD, PTB1/RxD | IRSCI serial I/O | Full-duplex UART pins supporting infrared carrier modulation via IRSCI module |
| VLCD | LCD bias voltage output | Internally generated bias voltage for LCD segment/backplane drive; adjustable via configuration bits |
| CGMXFC | PLL filter capacitor connection | External capacitor sets PLL loop bandwidth; required for stable PLL lock and jitter performance |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Real-Time Clock | Full calendar (year/month/day/weekday/hour/minute/second), alarm, chronograph, and ±127 ppm calibration register |
| Infrared Serial Interface (IRSCI) | IrDA 1.0-compliant physical layer with programmable carrier frequency (38 kHz), pulse width, and modulation depth |
| LCD Driver | Hardware-multiplexed 32-segment display support with VLCD generation and contrast control via software |
| FLASH Security | Block-level protection with CONFIG register lock bits preventing unauthorized read/write/erase access |
| Low-Power Operation | Stop mode current < 1 µA (typical) with RTC running; wake-up via IRQ, KBI, or RTC alarm interrupt |
Applications
| Industrial Panel Meters | Medical Patient Monitors |
|---|---|
Use Scenario: Standalone digital panel meter with local LCD display, pushbutton interface, and serial data logging. IC Role / Device Role / Timing Role: Main controller executing measurement algorithms, driving 4×8 LCD, managing button interrupts, and transmitting data via IRSCI to host PC. Use Value: Integrated RTC enables timestamped data logging; 24 KB FLASH accommodates firmware + calibration tables; low-power stop mode extends battery life between readings. | Use Scenario: Portable vital signs monitor with ECG/SpO₂ front-end, segmented LCD, and infrared data upload to nurse station. IC Role / Device Role / Timing Role: System-on-chip managing analog sensor interface (ADC), real-time display update, patient alarm triggering, and IrDA-compliant data transmission. Use Value: Hardware RTC ensures accurate clinical time stamps; IRSCI eliminates cables and EMI concerns; LCD driver reduces external component count. |
| Smart Utility Meters | Home Appliance Control Panels |
Use Scenario: Battery-powered gas/water meter with pulse counting, LCD display, tamper detection, and periodic infrared data retrieval. IC Role / Device Role / Timing Role: Primary MCU handling metrology counters, LCD refresh, low-voltage monitoring (LVI), and secure firmware updates via IRSCI. Use Value: Stop-mode current < 1 µA enables >10-year battery life; FLASH block protection prevents malicious firmware overwrite; RTC maintains billing timestamps during power loss. | Use Scenario: Microwave oven or washing machine control panel with keypad, 3-digit LCD, buzzer, relay drivers, and safety interlock monitoring. IC Role / Device Role / Timing Role: Dedicated UI controller managing scan-based keyboard input, segment LCD drive, audible feedback, and appliance state sequencing. Use Value: Integrated KBI and LCD driver eliminate external decoder ICs; 512 B RAM suffices for state machine variables; IRSCI enables service technician diagnostics without opening enclosure. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microcontroller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC68HC908LK24CPB | Same core and memory size but adds CAN 2.0A interface; no IRSCI or LCD driver | Targeted at automotive body electronics requiring fieldbus communication, not LCD/IR interfaces | Select when CAN bus connectivity is required over infrared or display capability |
| S9KEAZ128AMLH | Kinetis E-series ARM Cortex-M0+ core; 128 KB FLASH, 16 KB RAM, no integrated RTC or LCD driver | Higher performance, modern toolchain support, but requires external RTC and display controller | Select for new designs needing scalability, USB, or advanced peripherals - not drop-in replacement |
Compared with MC68HC908LK24CPB, the MC68HC908LJ24CPB trades CAN for IRSCI and LCD driver - making it optimal for infrared-linked, display-intensive embedded devices. Versus S9KEAZ128AMLH, it offers lower BOM cost and simpler firmware for legacy 8-bit applications but lacks ARM ecosystem advantages.
Availability
MC68HC908LJ24CPB is available at Aetrix Electronics and suitable for industrial panel meters, medical patient monitors, smart utility meters, and home appliance control panels requiring stable component supply and long-term lifecycle support.
Supply support for MC68HC908LJ24CPB 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
Freescale Semiconductor (now part of NXP Semiconductors) designed high-reliability, mixed-signal microcontrollers for industrial and automotive applications with emphasis on integration and low-power operation.
The MC68HC908LJ24CPB belongs to the HCS08 family, engineered specifically for cost-sensitive, battery-operated systems requiring real-time clock, LCD display, and infrared communication - without external support ICs.
FAQ
What is the maximum operating frequency of the MC68HC908LJ24CPB?
The MC68HC908LJ24CPB supports a maximum bus frequency of 8 MHz, achieved via its internal PLL using either an external crystal (1–8 MHz) or internal RC oscillator. This frequency governs instruction execution speed, timer resolution, and peripheral timing - all specified under DC characteristics in Section 24 of the datasheet.
Does the MC68HC908LJ24CPB support in-circuit programming?
Yes, the MC68HC908LJ24CPB supports in-circuit programming via its Monitor ROM (MON) using the IRSCI interface at standard baud rates (e.g., 9600 or 19200 bps). The MON provides bootloader routines (PRGRNGE, ERARNGE, LDRNGE) for FLASH programming without requiring a dedicated programmer - essential for field firmware updates.
How does the RTC in the MC68HC908LJ24CPB maintain accuracy across temperature variations?
The MC68HC908LJ24CPB RTC achieves ±1.5 ppm typical accuracy using a 32.768 kHz crystal and includes a calibration register (RTCCOMR) allowing ±127 ppm fine-tuning. Calibration values are stored in FLASH and applied at runtime - enabling compensation for crystal aging and temperature drift without external circuitry.
Can the MC68HC908LJ24CPB drive a 4-bit multiplexed LCD directly?
Yes, the MC68HC908LJ24CPB integrates a hardware LCD driver supporting up to 4 backplanes and 8 frontplanes (32 segments), including VLCD bias generation and contrast control. It natively drives 4×8 multiplexed LCDs without external charge pumps or bias resistors - verified in Section 17 of the datasheet.
What low-power modes are available on the MC68HC908LJ24CPB and how do they affect RTC operation?
The MC68HC908LJ24CPB supports Wait and Stop modes. In Stop mode, CPU and most peripherals halt while the RTC continues running from its 32.768 kHz oscillator - drawing < 1 µA (typical). Wake-up occurs via RTC alarm, IRQ, or KBI, preserving calendar integrity across deep sleep periods.
MC68HC908LJ24CPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Package/Case:
- 64-LQFP
- Series:
- HC08
- Packaging:
- Tray
- Product Status:
- Obsolete
- Programmable:
- Verified
- Core Processor:
- HC08
- Core Size:
- 8-Bit
- Speed:
- 8MHz
- Connectivity:
- I2C, IRSCI, SPI
- Peripherals:
- LCD, LVD, POR, PWM
- Number of I/O:
- 40
- Program Memory Size:
- 24KB (24K x 8)
- Program Memory Type:
- FLASH
- EEPROM Size:
- -
- RAM Size:
- 768 x 8
- Voltage - Supply (Vcc/Vdd):
- 3V ~ 5.5V
- Data Converters:
- A/D 6x10b
- Oscillator Type:
- Internal
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
MC68HC908LJ24CPB FAQ
1.How can I place an order for MC68HC908LJ24CPB through Aetrix?
Please submit a Request for Quotation (RFQ) for MC68HC908LJ24CPB on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MC68HC908LJ24CPB reliable?
The price and inventory of MC68HC908LJ24CPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC68HC908LJ24CPB is usually 5 days.
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Once your MC68HC908LJ24CPB order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MC68HC908LJ24CPB?
For technical support, including MC68HC908LJ24CPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC68HC908LJ24CPB requirements.
6.How does Aetrix verify that MC68HC908LJ24CPB is sourced from the original manufacturer or authorized distributors?
All MC68HC908LJ24CPB products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MC68HC908LJ24CPB meets industry standards.
7.What is the process for return or replacement of MC68HC908LJ24CPB?
All MC68HC908LJ24CPB units undergo pre-shipment inspection (PSI). If there is an issue with MC68HC908LJ24CPB, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MC68HC908LJ24CPB part is unused and in its original packaging.
Return procedure for MC68HC908LJ24CPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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