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NXP Semiconductors MC68HC908QT1CDW
- Part No.:
- MC68HC908QT1CDW
- Manufacturer:
- NXP Semiconductors
- Category:
- Microcontrollers
- Package:
- 8-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
MC68HC908QT1CDW.pdf
- Description:
- IC MCU 8BIT 1.5KB FLASH 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,245
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Product details
Overview
MC68HC908QT1CDW from NXP (formerly Freescale) is an 8-bit HCS08-core microcontroller with 1 KB FLASH, 64 bytes RAM, and integrated 8-channel 8-bit ADC. It features a precision internal RC oscillator (±2% over temperature), low-voltage inhibit (LVI), computer operating properly (COP) watchdog, and keyboard interrupt module - designed for cost-sensitive embedded control in appliance motor drives and industrial sensor interfaces.
For engineers reviewing the MC68HC908QT1CDW datasheet, MC68HC908QT1CDW pinout, MC68HC908QT1CDW application, or MC68HC908QT1CDW equivalent, key selection criteria include its 8-pin SOIC-W package, 4 MHz max bus clock, on-chip oscillator trim register (OSCTRIM), IRQ/KBI wake-up capability, and support for WAIT/STOP low-power modes in battery-operated systems.
Technical Context
The MC68HC908QT1CDW implements the M68HC08 CPU core with 16-bit address space, supporting indexed, extended, and relative addressing. Its memory map includes 1 KB of reprogrammable FLASH (with block protection), 64 bytes of RAM, and dedicated I/O registers mapped to $00–$3F.
Peripherals include an 8-channel 8-bit ADC with software-selectable conversion time (16–64 µs), Auto Wakeup Module (AWU) with programmable timeout (1–1024 ms), and System Integration Module (SIM) managing reset sources, COP, LVI, and oscillator switching between internal RC and external crystal modes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| CPU Core | M68HC08 8-bit CISC core with 16-bit address bus and 8-bit data bus |
| FLASH Memory | 1 KB on-chip FLASH with page erase, mass erase, and block protection register (FLBPR) |
| RAM Size | 64 bytes of on-chip RAM, retained in WAIT mode but lost in STOP mode |
| ADC Resolution | 8-bit successive-approximation ADC with 8 input channels and software-triggered conversion |
| Max Bus Clock | 4 MHz (derived from internal RC oscillator or external source; BUSCLKX4 option available) |
| Oscillator Accuracy | ±2% over –40°C to +85°C with factory-trimmed internal RC oscillator (no external crystal required) |
| Supply Voltage | 2.7 V to 5.5 V operation - supports direct interface with 3.3 V and 5 V logic systems |
Pinout & Package
MC68HC908QT1CDW is housed in an 8-pin SOIC-W (Wide-body) package (case #751BD), measuring 5.3 mm × 5.3 mm × 1.75 mm, with 1.27 mm pitch and gull-wing leads. Pinout validated per Figure 1-2 and Table 1-2 of MC68HC908QY/QT Family Data Sheet, Rev. 6.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD | Power supply | Primary 2.7–5.5 V supply rail; decoupling capacitor required at pin |
| VSS | Ground | Digital ground reference; must be connected to system GND plane |
| PTA0/IRQ | Port A bit 0 / External interrupt input | Configurable as general-purpose I/O or edge-triggered IRQ source with priority over KBI |
| PTA1/KBI0 | Port A bit 1 / Keyboard interrupt input 0 | Active-low wake-up input; supports debounced scan matrix with auto-debounce timing |
| PTA2/KBI1 | Port A bit 2 / Keyboard interrupt input 1 | Second KBI input; shares same interrupt vector as PTA1; enables 2-key matrix detection |
| PTA3/OSC1 | Port A bit 3 / Crystal amplifier input | Connects to XTAL1 of external crystal; unused when internal RC oscillator selected |
| PTA4/OSC2/BUSCLKX4 | Port A bit 4 / Crystal amplifier output / 4× bus clock output | Drives crystal load or outputs BUSCLKX4 signal; also functions as general I/O when not used for clock |
| RESET | Active-low reset input | Pulled high internally; external pull-up recommended; triggers cold start and COP/LVI resets |
Key Features
| Feature | Design Value |
|---|---|
| Internal RC Oscillator with Trim Register | Factory-trimmed ±2% accuracy; OSCTRIM register allows field calibration via software |
| Low-Voltage Inhibit (LVI) | Detects VDD drop below 2.5 V (typ.) and forces reset - prevents erratic code execution during brownout |
| Computer Operating Properly (COP) | Watchdog timer with selectable timeout (0.5–16 ms); requires periodic service to avoid system reset |
| Keyboard Interrupt Module (KBI) | Two dedicated wake-up inputs (KBI0/KBI1) with configurable edge sensitivity and interrupt flag clearing |
| Auto Wakeup Module (AWU) | Programmable sleep timer (1–1024 ms) enabling precise duty-cycled operation without external RTC |
Applications
| Home Appliance Control | Industrial Sensor Interface |
|---|---|
|
Use Scenario: Embedded control of washing machine drum motor, water valve, and user interface panel. IC Role / Device Role / Timing Role: Primary MCU executing state-machine logic, reading push-button inputs via KBI, and driving relay/LED outputs via Port A. Use Value: Integrated LVI and COP ensure reliable operation during voltage fluctuations common in AC-powered appliances; 1 KB FLASH accommodates firmware with fault diagnostics. |
Use Scenario: Battery-powered temperature/humidity sensor node transmitting data via UART to gateway. IC Role / Device Role / Timing Role: Low-power data acquisition controller sampling analog sensors via 8-bit ADC and entering STOP mode between readings. Use Value: AWU enables 1-second wake intervals with <1 µA STOP current; internal oscillator eliminates need for external crystal, reducing BOM cost and board area. |
| Smart Power Outlet | Motorized Window Actuator |
|
Use Scenario: Wi-Fi-enabled outlet monitoring load current and enforcing safety cutoff thresholds. IC Role / Device Role / Timing Role: Safety monitor co-processor interfacing with main SoC via UART, validating current-sense ADC readings and asserting hardware shutdown. Use Value: Dedicated IRQ pin allows immediate response to overcurrent events; 64-byte RAM retains critical fault flags across low-power transitions. |
Use Scenario: DC motor control for automated window blinds with position feedback and obstacle detection. IC Role / Device Role / Timing Role: Motion controller reading potentiometer (ADC), detecting stall via current sense, and managing bidirectional H-bridge drive signals. Use Value: 8-channel ADC supports simultaneous sensing of position, voltage, and motor current; KBI pins detect manual override switches without polling overhead. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 8-bit microcontroller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC68HC908QT2CDW | 2 KB FLASH, same 8-pin SOIC-W package and peripheral set; identical pinout and voltage range | Supports larger firmware with bootloader, enhanced diagnostics, or dual-application partitioning | Select when firmware size exceeds 1 KB or future scalability is required without PCB change |
| MC9RS08KA2CSC | Renesas RS08 core; 2 KB FLASH, 128 bytes RAM; 8-pin SOIC package; no KBI module but adds SPI/I²C | Better suited for communication-centric designs requiring serial protocol offload | Choose when system requires on-chip SPI/I²C instead of keyboard wake-up; note different instruction set and toolchain |
Compared with MC68HC908QT2CDW and MC9RS08KA2CSC, the MC68HC908QT1CDW offers optimal cost/performance balance for minimal-footprint control tasks where KBI wake-up and sub-1 KB firmware are sufficient - avoiding over-provisioned memory or unnecessary peripherals.
Availability
MC68HC908QT1CDW is available at Aetrix Electronics and suitable for home appliance control, industrial sensor interface, and smart power outlet applications requiring stable component supply and long-term industrial lifecycle support.
Supply support for MC68HC908QT1CDW 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 delivering secure, scalable solutions for automotive, industrial, IoT, and mobile applications - formed from the spin-off of Freescale Semiconductor in 2015.
The MC68HC908QT1CDW belongs to the legacy HCS08 microcontroller family, designed specifically for ultra-low-cost, low-pin-count embedded control in resource-constrained environments where reliability, ease of programming, and minimal external components are critical.
FAQ
What is the maximum operating frequency of the MC68HC908QT1CDW?
The MC68HC908QT1CDW supports a maximum bus clock frequency of 4 MHz. This is derived either from its internal trimmed RC oscillator (factory calibrated to ±2%) or from an external crystal source. The BUSCLKX4 signal can be enabled to output a 4× clock for debugging or synchronization purposes, but the core execution speed remains governed by the 4 MHz bus clock limit.
Does the MC68HC908QT1CDW include a hardware watchdog timer?
Yes, the MC68HC908QT1CDW integrates a Computer Operating Properly (COP) watchdog timer. It features configurable timeout periods ranging from 0.5 ms to 16 ms and requires periodic servicing via the COPCTL register to prevent automatic system reset - ensuring robust recovery from software hangs or infinite loops in safety-critical applications.
Can the MC68HC908QT1CDW operate without an external crystal?
Yes, the MC68HC908QT1CDW operates fully autonomously using its internal RC oscillator, which is factory-trimmed for ±2% accuracy across –40°C to +85°C. External crystals are optional and only required if higher timing precision is needed; OSC1/OSC2 pins default to GPIO functionality when the internal oscillator is selected.
How much FLASH memory does the MC68HC908QT1CDW have, and is it reprogrammable in-circuit?
The MC68HC908QT1CDW contains 1 KB of on-chip FLASH memory that is fully reprogrammable in-system via single-wire background debug mode (BDM). It supports page erase, mass erase, and block protection via the FLBPR register - enabling secure firmware updates and field upgrades without removing the device from the PCB.
What low-power modes does the MC68HC908QT1CDW support, and what is the typical current draw in STOP mode?
The MC68HC908QT1CDW supports WAIT and STOP low-power modes. In STOP mode, typical current consumption is less than 1 µA at 3.3 V and 25°C, with RAM retention disabled. Wake-up sources include IRQ, KBI, AWU timeout, and RESET assertion - making it suitable for battery-powered applications requiring multi-day standby life.
MC68HC908QT1CDW 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:
- 1.5KB (1.5K x 8)
- Program Memory Type:
- FLASH
- EEPROM Size:
- -
- RAM Size:
- 128 x 8
- Voltage - Supply (Vcc/Vdd):
- 2.7V ~ 5.5V
- Data Converters:
- -
- Oscillator Type:
- Internal
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
MC68HC908QT1CDW FAQ
1.How can I place an order for MC68HC908QT1CDW through Aetrix?
Please submit a Request for Quotation (RFQ) for MC68HC908QT1CDW 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 MC68HC908QT1CDW reliable?
The price and inventory of MC68HC908QT1CDW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC68HC908QT1CDW is usually 5 days.
3.What payment methods are accepted for MC68HC908QT1CDW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC68HC908QT1CDW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC68HC908QT1CDW?
MC68HC908QT1CDW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC68HC908QT1CDW 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 MC68HC908QT1CDW?
For technical support, including MC68HC908QT1CDW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC68HC908QT1CDW requirements.
6.How does Aetrix verify that MC68HC908QT1CDW is sourced from the original manufacturer or authorized distributors?
All MC68HC908QT1CDW 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 MC68HC908QT1CDW meets industry standards.
7.What is the process for return or replacement of MC68HC908QT1CDW?
All MC68HC908QT1CDW units undergo pre-shipment inspection (PSI). If there is an issue with MC68HC908QT1CDW, 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 MC68HC908QT1CDW part is unused and in its original packaging.
Return procedure for MC68HC908QT1CDW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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