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NXP Semiconductors MC68HC908QT4CDW
- Part No.:
- MC68HC908QT4CDW
- Manufacturer:
- NXP Semiconductors
- Category:
- Microcontrollers
- Package:
- 8-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
MC68HC908QT4CDW.pdf
- Description:
- IC MCU 8BIT 4KB FLASH 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:2,439
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Product details
Overview
MC68HC908QT4CDW from NXP (formerly Freescale) is an 8-bit HCS08-core microcontroller with 4 KB on-chip FLASH, 192 B RAM, and integrated 8-channel 8-bit ADC. It features internal RC oscillator (1–8 MHz), low-voltage inhibit (LVI), computer operating properly (COP) watchdog, and keyboard interrupt (KBI) for touch/switch interfaces. Designed for cost-sensitive embedded control in appliance panels, industrial sensors, and power tool controllers.
For engineers reviewing the MC68HC908QT4CDW datasheet, MC68HC908QT4CDW pinout, MC68HC908QT4CDW application, or MC68HC908QT4CDW equivalent, key selection criteria include its 16-pin SOIC-W package, 5 V operation, on-chip oscillator trim register (OSCTRIM), KBI wake-up capability, and FLASH block protection - all critical for reliable, field-programmable low-power control designs.
Technical Context
The MC68HC908QT4CDW implements the M68HC08 CPU core with 16-bit address bus and Harvard architecture. Its oscillator module supports internal RC, external crystal (XTAL), or external clock input, with automatic switching and trimming via OSCTRIM register at $FFC0. The SIM integrates reset control, IRQ handling, and COP supervision with configurable timeout.
Peripheral integration includes a 16-bit TIM with input capture/output compare, 8-channel ADC with programmable conversion clock prescaler, and dual I/O ports (Port A: 8-bit bidirectional with KBI; Port B: 4-bit with IRQ). All modules operate under unified low-power modes: WAIT (CPU halted, peripherals active) and STOP (full clock gating).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| CPU Core | M68HC08 8-bit CISC core, 8 MHz max bus frequency (BUSCLKX2 mode) |
| Memory | 4 KB on-chip FLASH (user-programmable, block-protectable), 192 B RAM |
| ADC | 8-channel 8-bit successive-approximation ADC; 13 µs typical conversion time at 1 MHz ADC clock |
| Oscillator | Internal RC oscillator (1–8 MHz, factory-trimmed ±2% @ 5 V); supports XTAL (1–8 MHz) and external clock input |
| I/O Ports | Port A: 8-bit bidirectional with KBI; Port B: 4-bit bidirectional with IRQ; all pins CMOS-compatible, 5 V tolerant |
| Supply Voltage | 4.5 V to 5.5 V operation; LVI threshold fixed at 4.0 V ±0.2 V with hysteresis |
| Package | 16-pin SOIC-W (Wide), 7.5 mm body width, 1.27 mm pitch, RoHS-compliant |
Pinout & Package
MC68HC908QT4CDW is housed in a 16-pin SOIC-W (Small Outline Integrated Circuit – Wide) package per Freescale package code DW. Pin assignments are defined in Figure 1-2 and Table 1-2 of Rev. 6 datasheet, with shared functions prioritized per Table 1-3.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD | Power supply | Primary 5 V supply input; decoupling capacitor required at pin |
| VSS | Ground | Digital ground reference; must be connected to system GND plane |
| PTA0–PTA7 | Port A data lines | Bidirectional I/O with KBI interrupt capability; PTA0–PTA3 also serve as ADC inputs |
| PTB0–PTB3 | Port B data lines | Bidirectional I/O with IRQ interrupt capability; PTB0 doubles as RESET input |
| OSC1 / XTALIN | Clock input | Crystal amplifier input or external clock source; requires 32.768 kHz or 1–8 MHz crystal |
| OSC2 / PTA4 / BUSCLKX4 | Clock output / I/O / clock signal | Crystal amplifier output; also serves as PTA4 and 4× bus clock output |
| IRQ | External interrupt | Active-low edge-triggered interrupt input; shares pin with PTB0 when MODE=1 |
| RESET | Reset input | Active-low asynchronous reset; internal pull-up; accepts 5 V logic levels |
Key Features
| Feature | Design Value |
|---|---|
| On-chip oscillator trimming | OSCTRIM register ($FFC0) enables software calibration of internal RC oscillator for ±0.5% accuracy over voltage/temperature |
| FLASH block protection | FLBPR register ($FFBE) allows locking individual 512-byte FLASH blocks against accidental erase/write |
| Keyboard interrupt (KBI) | Hardware scan of up to 8 keys on Port A; generates interrupt on key press/release without CPU polling |
| Low-voltage inhibit (LVI) | Dedicated analog comparator monitors VDD; forces reset if voltage drops below 4.0 V ±0.2 V with 100 mV hysteresis |
| COP watchdog timer | Configurable timeout (0.5 ms to 1.0 s) with independent clock source; prevents runaway code execution |
Applications
| Appliance Control Panel | Industrial Sensor Node |
|---|---|
Use Scenario: Microcontroller manages LED indicators, push-button inputs, and buzzer feedback in microwave oven or washing machine control panel. IC Role / Device Role / Timing Role: MC68HC908QT4CDW acts as primary user-interface controller, executing state-machine logic and scanning keypad via KBI module. Use Value: Integrated KBI eliminates external scan logic; on-chip FLASH enables field firmware updates; LVI ensures safe shutdown during brownout. | Use Scenario: Standalone sensor node measures temperature and humidity, transmits data via UART to gateway, and enters STOP mode between readings. IC Role / Device Role / Timing Role: MC68HC908QT4CDW serves as sensor acquisition and low-power scheduler, using AWU to wake every 10 s for ADC sampling. Use Value: 192 B RAM suffices for sensor buffers; internal RC oscillator avoids crystal BOM cost; STOP current < 1 µA extends battery life. |
| Power Tool Motor Controller | LED Lighting Driver Interface |
Use Scenario: MCU monitors trigger switch, battery voltage, and motor temperature in cordless drill, controlling MOSFET gate drive via PWM. IC Role / Device Role / Timing Role: MC68HC908QT4CDW functions as safety-critical motor supervisor, using COP watchdog and LVI to prevent unsafe operation. Use Value: COP timeout set to 500 ms ensures immediate reset on firmware hang; LVI reset at 4.0 V prevents MOSFET shoot-through during low-battery conditions. | Use Scenario: MCU interfaces with ambient light sensor and dimmer potentiometer to adjust white LED brightness in architectural lighting fixture. IC Role / Device Role / Timing Role: MC68HC908QT4CDW performs analog sensing (ADC), digital input processing (KBI for mode buttons), and PWM generation for LED current control. Use Value: 8-channel ADC supports multi-sensor inputs; KBI handles button debouncing in hardware; 4 KB FLASH stores dimming curves and calibration data. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 8-bit microcontroller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC9RS08KA2CP | RS08 core, 2 KB FLASH, no KBI, 10-bit ADC, 16-pin SOIC | Lacks hardware keyboard interrupt; requires software scanning for button inputs | Choose when lower cost and simpler peripheral set suffice; not suitable for high-reliability KBI-dependent UIs |
| STM8S003F3P6 | STM8 core, 8 KB FLASH, 1 KiB RAM, 10-bit ADC, 16-pin SOIC, 3.3 V only | Requires level-shifting for 5 V systems; no native 5 V I/O; different debug interface (SWIM vs. MON) | Prefer for new 3.3 V designs needing more memory; avoid in legacy 5 V industrial systems without voltage translation |
Compared with MC9RS08KA2CP and STM8S003F3P6, the MC68HC908QT4CDW provides verified KBI hardware, 5 V native I/O, and factory-trimmed oscillator - making it uniquely suited for cost-sensitive, robust 5 V appliance control where button responsiveness and supply resilience are non-negotiable.
Availability
MC68HC908QT4CDW is available at Aetrix Electronics and suitable for appliance control panels, industrial sensor nodes, and power tool motor supervisors requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for MC68HC908QT4CDW 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 formed from the spin-off of Philips' semiconductor division, now specializing in secure connectivity, automotive, and industrial microcontrollers.
The MC68HC908QT4CDW belongs to the legacy HCS08 family, designed specifically for low-cost, low-power embedded control in consumer and industrial equipment where reliability, ease of programming, and minimal external components are essential.
FAQ
What is the maximum operating frequency of the MC68HC908QT4CDW?
The MC68HC908QT4CDW supports a maximum bus clock frequency of 8 MHz in BUSCLKX2 mode, derived from its internal RC oscillator or external crystal source. When using the internal oscillator, factory trimming ensures ±2% accuracy at 5 V; software trimming via OSCTRIM register can improve stability across voltage and temperature variations. The MC68HC908QT4CDW does not support PLL multiplication beyond this base frequency.
Does the MC68HC908QT4CDW support in-circuit programming?
Yes, the MC68HC908QT4CDW supports in-circuit programming via its MON (Monitor) module using a single-wire background debug interface. Programming requires a compatible Freescale/NXP BDM debugger and the MC68HC908QT4CDW's dedicated BKGD pin (shared with PTA7). Flash memory can be erased and reprogrammed in-system without removing the device from the PCB.
What is the purpose of the OSCTRIM register in the MC68HC908QT4CDW?
The OSCTRIM register ($FFC0) in the MC68HC908QT4CDW allows runtime adjustment of the internal RC oscillator's frequency by modifying the oscillator's load capacitance value. This enables software-based calibration to compensate for process, voltage, and temperature drift - achieving ±0.5% accuracy after trimming. The MC68HC908QT4CDW uses this register to maintain timing-critical functions like UART baud generation and ADC sampling intervals.
Can the MC68HC908QT4CDW operate from a 3.3 V supply?
No, the MC68HC908QT4CDW is specified for 4.5 V to 5.5 V operation only. Its internal LVI threshold is fixed at 4.0 V ±0.2 V, and its I/O structure is designed for 5 V CMOS logic levels. Operating below 4.5 V risks undefined behavior, failed resets, or inability to meet AC timing specifications. For 3.3 V systems, consider the RS08- or S08-based alternatives explicitly rated for that voltage range.
How many interrupt sources does the MC68HC908QT4CDW support?
The MC68HC908QT4CDW supports 14 interrupt vectors, including IRQ (external), KBI (keyboard), ADC conversion complete, TIM overflow/input capture/output compare, COP timeout, LVI trip, and reset. Each has configurable priority and vector address in the interrupt vector table located at $FFD0–$FFFF. The MC68HC908QT4CDW handles nested interrupts only when enabled via the global interrupt mask (I bit in CCR).
MC68HC908QT4CDW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Package/Case:
- 8-SOIC (0.209", 5.30mm Width)
- Series:
- HC08
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Core Processor:
- HC08
- Core Size:
- 8-Bit
- Speed:
- 8MHz
- Connectivity:
- -
- Peripherals:
- LVD, POR, PWM
- Number of I/O:
- 5
- Program Memory Size:
- 4KB (4K x 8)
- Program Memory Type:
- FLASH
- EEPROM Size:
- -
- RAM Size:
- 128 x 8
- Voltage - Supply (Vcc/Vdd):
- 2.7V ~ 5.5V
- Data Converters:
- A/D 4x8b
- Oscillator Type:
- Internal
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
MC68HC908QT4CDW FAQ
1.How can I place an order for MC68HC908QT4CDW through Aetrix?
Please submit a Request for Quotation (RFQ) for MC68HC908QT4CDW 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 MC68HC908QT4CDW reliable?
The price and inventory of MC68HC908QT4CDW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC68HC908QT4CDW is usually 5 days.
3.What payment methods are accepted for MC68HC908QT4CDW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC68HC908QT4CDW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC68HC908QT4CDW?
MC68HC908QT4CDW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC68HC908QT4CDW 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 MC68HC908QT4CDW?
For technical support, including MC68HC908QT4CDW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC68HC908QT4CDW requirements.
6.How does Aetrix verify that MC68HC908QT4CDW is sourced from the original manufacturer or authorized distributors?
All MC68HC908QT4CDW 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 MC68HC908QT4CDW meets industry standards.
7.What is the process for return or replacement of MC68HC908QT4CDW?
All MC68HC908QT4CDW units undergo pre-shipment inspection (PSI). If there is an issue with MC68HC908QT4CDW, 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 MC68HC908QT4CDW part is unused and in its original packaging.
Return procedure for MC68HC908QT4CDW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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