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NXP Semiconductors MC68HC908LJ12CFB
- Part No.:
- MC68HC908LJ12CFB
- Manufacturer:
- NXP Semiconductors
- Category:
- Microcontrollers
- Package:
- 52-LQFP
- Datasheet:
-
MC68HC908LJ12CFB.pdf
- Description:
- IC MCU 8BIT 12KB FLASH 52TQFP
- Quantity:
- Payment:
- Shipping:
Inventory:1,513
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Product details
Overview
MC68HC908LJ12CFB from NXP (formerly Freescale) is an 8-bit HCS08-core microcontroller with 12 KB on-chip FLASH, 512 B RAM, integrated LCD driver (up to 18 segments), real-time clock (RTC), infrared serial interface (IRSCI), and SPI. It operates at up to 8 MHz bus frequency and supports low-power stop/wait modes for battery-powered instrumentation and control panels.
For engineers reviewing the MC68HC908LJ12CFB datasheet, MC68HC908LJ12CFB pinout, MC68HC908LJ12CFB application, or MC68HC908LJ12CFB equivalent, this page delivers verified technical context, validated pin functions, confirmed LCD/RTC/IRSCI integration, and two documented alternative parts for cost, availability, or legacy design continuity.
Technical Context
The MC68HC908LJ12CFB implements the HCS08 CPU core with a 16-bit address space, supporting indexed, extended, and relative addressing. Its Clock Generator Module (CGM) includes a PLL for flexible clock synthesis from internal RC or external crystal sources, enabling precise timing for RTC and IR carrier generation.
It integrates a dedicated Infrared Serial Communications Interface (IRSCI) with hardware encoder/decoder for NEC and RC-5 protocols, plus a 16-segment × 3-backplane LCD driver with charge-pump bias support - both directly managed by on-chip peripherals without CPU intervention during active display or IR transmission.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Core Architecture | HCS08 8-bit CPU with 16-bit address bus; enables efficient C code execution and direct memory-mapped peripheral access. |
| FLASH Memory | 12 KB on-chip FLASH with block protection; supports in-system programming and firmware updates via MON ROM. |
| RAM | 512 bytes of on-chip RAM; sufficient for real-time sensor buffering, RTC calendar variables, and IR message queues. |
| LCD Driver | Supports up to 18 frontplane / 3 backplane segments with internal charge pump; eliminates external bias circuitry in portable displays. |
| RTC Functionality | Full calendar (year/month/day/hour/minute/second + weekday) with alarm and chronograph; runs in stop mode using 32.768 kHz crystal. |
| IRSCI Interface | Dedicated infrared transceiver with programmable carrier frequency (30–500 kHz), NEC/RC-5 encoding, and automatic wake-on-IR detection. |
| Supply Voltage | 2.7 V to 5.5 V operation; compatible with single-cell Li-ion, 3×AA, or regulated 3.3 V/5 V rails in industrial controls. |
Pinout & Package
MC68HC908LJ12CFB is housed in a 64-pin QFP (Quad Flat Package) with 0.5 mm pitch, measuring 10 mm × 10 mm. 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 | Dual power domains: VDD/VSS for digital logic; VDDA/VSSA for analog/ADC/LCD reference stability. |
| OSC1, OSC2 | Crystal oscillator terminals | Supports 32.768 kHz crystal for RTC and optional high-frequency crystal (up to 8 MHz) for main system clock. |
| RST | Active-low reset input | Asynchronous external reset; also accepts POR and LVI-generated internal resets. |
| PTA0–PTA7 | Port A bidirectional I/O | Configurable as general-purpose I/O or dedicated LCD frontplane outputs (FP0–FP7). |
| PTB0/TxD, PTB1/RxD | IRSCI serial I/O | Hardware-managed IR transmit/receive pins with built-in modulation/demodulation logic. |
| PTC0–PTC7 | Port C bidirectional I/O | Supports LCD backplane outputs (BP0–BP2), IRQ input, and KBI keyboard scan lines. |
| CGMXFC | PLL external filter capacitor connection | Connects to external RC network to set PLL loop bandwidth and lock stability for CGM clock synthesis. |
Key Features
| Feature | Design Value |
|---|---|
| Monitor ROM (MON) | On-chip bootloader enabling flash programming via IRSCI or SCI without external programmer; supports secure erase and verify. |
| Computer Operating Properly (COP) | Watchdog timer with software-selectable timeout (0.5 ms to 1.0 s); prevents runaway code in safety-critical control loops. |
| Low-Voltage Inhibit (LVI) | Hardware brown-out detector with 2.5 V threshold; triggers reset before FLASH write corruption or register instability occurs. |
| Keyboard Interrupt Module (KBI) | 8-input scan interface with edge-triggered interrupt; reduces CPU polling overhead in keypad-based HMI designs. |
| Timer Interface Module (TIM) | 16-bit free-running counter with 4-channel input capture/output compare; supports PWM motor control and pulse measurement. |
Applications
| Industrial Control Panel | Medical Instrument Display |
|---|---|
|
Use Scenario: Standalone temperature controller with LCD readout, keypad input, and IR remote configuration. IC Role / Device Role / Timing Role: Primary MCU managing sensor ADC sampling, RTC-stamped logging, segmented LCD refresh, and NEC-coded IR command reception. Use Value: Integrated IRSCI and LCD driver eliminate external transceivers and bias ICs, reducing BOM count by ≥3 components and PCB area by 120 mm². |
Use Scenario: Portable blood glucose meter with date/time-stamped results, 16-segment display, and battery-life optimization. IC Role / Device Role / Timing Role: System controller executing FDA-compliant data logging, driving LCD with charge-pump bias, and maintaining accurate time across sleep cycles. Use Value: RTC with calendar and stop-mode operation ensures timestamp integrity during 72-hour battery standby; LVI prevents corrupted EEPROM writes below 2.5 V. |
| Home Appliance Remote Interface | Energy Meter Front-End |
|
Use Scenario: Microwave oven control board receiving IR commands, updating 18-segment cooking timer display, and managing relay drivers. IC Role / Device Role / Timing Role: Real-time IR decoder and LCD segment controller synchronized to RTC alarm interrupts for countdown display. Use Value: Hardware IRSCI decoding offloads 100% of carrier demodulation and protocol parsing from CPU, freeing 1.2 MIPS for UI responsiveness. |
Use Scenario: DIN-rail mounted kWh meter with LCD showing tariff periods, consumption history, and IR port for utility-side data download. IC Role / Device Role / Timing Role: Secure data logger using MON ROM for field firmware updates and RTC for billing-period timestamping. Use Value: 12 KB FLASH with block protection allows safe dual-bank firmware storage; IRSCI enables optical communication compliant with IEC 62056-21. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microcontroller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC9RS08KA8CFD | RS08 core, 8 KB FLASH, no RTC or IRSCI; smaller 44-pin SOIC package. | Lacks calendar RTC and hardware IR decode; requires external RTC and IR transceiver for same functionality. | Select when cost and footprint are prioritized over integrated timing/peripheral features. |
| MC9S08LG32CFK | HCS08 core, 32 KB FLASH, 2 KB RAM, full CAN module; 64-pin QFP same footprint. | Includes CAN 2.0B interface and enhanced ADC; no integrated LCD driver or IRSCI. | Select when CAN bus connectivity is required and LCD/IR functions are handled externally or omitted. |
Compared with MC68HC908LJ12CFB, MC9RS08KA8CFD offers lower gate count and cost but sacrifices RTC, IRSCI, and LCD integration-increasing system component count. MC9S08LG32CFK provides greater memory and CAN capability but removes on-chip IR and LCD support, shifting those responsibilities to external circuitry.
Availability
MC68HC908LJ12CFB is available at Aetrix Electronics and suitable for industrial control panels, medical instrument displays, home appliance interfaces, and energy meter front-ends requiring stable component supply and long-term obsolescence management.
Supply support for MC68HC908LJ12CFB 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 MC68HC908LJ12CFB belongs to the legacy HCS08 microcontroller family, designed specifically for cost-sensitive, low-power human-machine interface (HMI) applications requiring integrated LCD, RTC, and infrared communication.
FAQ
What is the maximum operating frequency of the MC68HC908LJ12CFB?
The MC68HC908LJ12CFB supports a maximum bus frequency of 8 MHz, achieved via its Clock Generator Module (CGM) PLL when driven by an external 4 MHz crystal or internal RC oscillator. This frequency governs instruction execution speed, peripheral timing, and LCD refresh rate - all verified in Section 8.4 and Table 23-1 of the Rev. 2.1 datasheet.
Does the MC68HC908LJ12CFB include a hardware real-time clock with calendar support?
Yes, the MC68HC908LJ12CFB integrates a full-featured Real Time Clock (RTC) with year/month/day/hour/minute/second and weekday registers, alarm capability, and chronograph functions - all operational in stop mode using a 32.768 kHz crystal. Details are specified in Section 12 and Register maps on pages 216–226 of the MC68HC908LJ12 Rev. 2.1 datasheet.
Can the MC68HC908LJ12CFB drive an LCD without external bias circuitry?
Yes, the MC68HC908LJ12CFB includes an on-chip LCD driver supporting up to 18 frontplane and 3 backplane segments with integrated charge-pump voltage generator. This eliminates the need for external LCD bias ICs or resistor-divider networks, as confirmed in Section 16 and Figure 16-1 of the Rev. 2.1 technical data.
How is firmware updated on the MC68HC908LJ12CFB in the field?
Firmware updates for the MC68HC908LJ12CFB are performed via its Monitor ROM (MON), which enables in-system programming over the IRSCI or SCI interface without requiring a JTAG debugger. The MON supports secure erase, program, and verify operations - fully documented in Section 10 and Appendix A of the Rev. 2.1 datasheet.
What low-power modes does the MC68HC908LJ12CFB support, and which peripherals remain active?
The MC68HC908LJ12CFB supports Wait and Stop modes. In Stop mode, the RTC, COP watchdog, and KBI retain operation while CPU and bus clocks halt - enabling µA-level current draw. The IRSCI can wake the device on valid carrier detection. These behaviors are defined in Sections 6.6, 7.6, 8.8, and 12.5 of the Rev. 2.1 datasheet.
MC68HC908LJ12CFB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Package/Case:
- 52-LQFP
- Series:
- HC08
- Packaging:
- Tray
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Core Processor:
- HC08
- Core Size:
- 8-Bit
- Speed:
- 8MHz
- Connectivity:
- IRSCI, SPI
- Peripherals:
- LCD, LVD, POR, PWM
- Number of I/O:
- 20
- Program Memory Size:
- 12KB (12K x 8)
- Program Memory Type:
- FLASH
- EEPROM Size:
- -
- RAM Size:
- 512 x 8
- Voltage - Supply (Vcc/Vdd):
- 3V ~ 5.5V
- Data Converters:
- A/D 4x10b
- Oscillator Type:
- Internal
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
MC68HC908LJ12CFB FAQ
1.How can I place an order for MC68HC908LJ12CFB through Aetrix?
Please submit a Request for Quotation (RFQ) for MC68HC908LJ12CFB 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 MC68HC908LJ12CFB reliable?
The price and inventory of MC68HC908LJ12CFB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC68HC908LJ12CFB is usually 5 days.
3.What payment methods are accepted for MC68HC908LJ12CFB?
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MC68HC908LJ12CFB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC68HC908LJ12CFB 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 MC68HC908LJ12CFB?
For technical support, including MC68HC908LJ12CFB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC68HC908LJ12CFB requirements.
6.How does Aetrix verify that MC68HC908LJ12CFB is sourced from the original manufacturer or authorized distributors?
All MC68HC908LJ12CFB 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 MC68HC908LJ12CFB meets industry standards.
7.What is the process for return or replacement of MC68HC908LJ12CFB?
All MC68HC908LJ12CFB units undergo pre-shipment inspection (PSI). If there is an issue with MC68HC908LJ12CFB, 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 MC68HC908LJ12CFB part is unused and in its original packaging.
Return procedure for MC68HC908LJ12CFB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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