MC68HC908QT1MPE - 8-bit HC08 MCU, 1.5KB Flash, 8-DIP | NXP
MPN: MC68HC908QT1MPE ⚠ Last Time Buy| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.42 | $3.42 |
| 10 | $2.97 | $29.70 |
| 100 | $2.46 | $246.00 |
| 500 | $2.18 | $1,090.00 |
| 1,000 | $1.95 | $1,950.00 |
MC68HC908QT1MPE Overview
An 8-bit microcontroller is a single-chip computer built around an 8-bit data bus and a Von Neumann or Harvard architecture, integrating CPU, RAM, ROM/Flash, and I/O peripherals onto one die. The HC08 family uses a Complex Instruction Set Computer (CISC) Von Neumann architecture, meaning the 8-bit CPU08 core fetches instructions and data over a shared 16-bit address bus. The HC08Q sub-family sits in the hierarchy as: 8-bit MCU -> HC08 family -> HC08Q sub-family -> low-cost, low-pin-count line, and is widely used for cost-sensitive consumer and industrial control where 32-bit ARM Cortex parts would be overkill.
Key features of the MC68HC908QT1MPE include 1.5KB (1.5K x 8) of Flash memory, 128 bytes of RAM, an internal 8MHz bus clock with a trimmable internal oscillator, 5 general-purpose I/O pins, on-chip LVD (Low-Voltage Detect) and POR (Power-On Reset), and a PWM module. The part runs from a 2.7V to 5.5V supply (industrial range), is specified for -40C to +85C operation, and uses an HC08 CPU08 core that executes one instruction per 2 to 13 bus cycles.
The HC08 architecture combines a small, deterministic 8-bit core with on-chip Flash, a flexible timer/PWM block, and a keyboard interrupt module that is well-suited to sensing and control loops. The QT1 variant strips the ADC for the smallest possible footprint, leaving the 5 bidirectional I/O pins to handle digital I/O, timer capture/compare, and PWM output. Programming is performed through a single-wire background debug mode (BDM) interface that uses two of the device pins, leaving three remaining for application use.
Typical applications for the MC68HC908QT1MPE include simple PWM motor control in small appliances, low-cost remote-control transmitters, LED lighting controllers, sensor signal conditioning with digital output, and battery-powered handheld devices. Its tiny 8-pin PDIP footprint and 1.5KB Flash make it a fit where 32-bit MCUs would add unnecessary BOM cost.
Designers should note that the 1.5KB Flash limits program size to roughly 1K instructions of HC08 assembly or 600-800 lines of C code. For designs that may grow, the HC08Q family offers pin-compatible parts with 2KB (QT2), 4KB (QT4), and ADC-equipped (QY) variants. The MC68HC908QT1MPE is also marked as End-of-Life on the NXP product page, so new designs should consider the pin-compatible QT2/QT4 family members or move to a modern S08 core.
Drop-in alternatives for MC68HC908QT1MPE — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with MC68HC908QT1MPE (same form factor and footprint) — differing in Core Processor, RAM Size, Maximum Clock Frequency, Mounting Type, Peripherals.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC68HC908QT2MPE
✅ Drop-In✓ In Stock
$1.95 / Unit
View Datasheet →MC68HC908QT4MPE
✅ Drop-In📋 Reference alternative (not in catalog)
MC68HC908QY1MPE
✅ Drop-In✓ In Stock
$0.55 / Unit
View Datasheet →MC9S08QG8CPE
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MC68HC908QT1MPE Maximum Ratings & Electrical Characteristics
| Core Processor | HC08 (CPU08) |
| Core Size | 8-Bit |
| Program Memory Size | 1.5 KB (1.5K x 8) Flash |
| RAM Size | 128 bytes (128 x 8) |
| Maximum Clock Frequency | 8 MHz (internal bus) |
| Supply Voltage Range | 2.7 V to 5.5 V |
| Number of I/O Pins | 5 |
| Peripherals | LVD, POR, PWM |
| Connectivity | None (no UART, no SPI, no I2C) |
| ADC | None |
| Package Type | 8-PDIP (8-pin Plastic DIP) |
| Mounting Type | Through-Hole |
| Operating Temperature | -40 C to +85 C (Industrial) |
| RoHS Status | Compliant |
| Lifecycle Status | Last Time Buy (per NXP product page) |
MC68HC908QT1MPE Pin Configuration
| Pin 1 | RST — Active-low reset input, internal pull-up |
| Pin 2 | IRQ/TCLK — External interrupt / Timer clock input |
| Pin 3 | VDD — Positive supply (2.7V to 5.5V) |
| Pin 4 | VSS — Ground |
| Pin 5 | PTA0/BKGD — GPIO PTA0, shared with BDM debug data |
| Pin 6 | PTA1 — GPIO PTA1 |
| Pin 7 | PTA2/BKGDCLK — GPIO PTA2, shared with BDM clock |
| Pin 8 | PTA3 — GPIO PTA3 |
Typical Applications
MC68HC908QT1MPE is suitable for 6 applications: Low-Cost PWM Motor Control, Simple LED Lighting Controllers, Remote Control and RF Keyfob Transmitters, Industrial Sensor Signal Conditioning, Battery-Powered Handheld Devices, Educational and Hobbyist Projects.
Low-Cost PWM Motor Control
The MC68HC908QT1MPE's on-chip PWM module and 5 I/O pins fit small brushed DC motor or low-frequency PWM control loops in appliances and toys. Driving a small N-channel MOSFET gate from PTA0 at up to 8MHz bus clock gives deterministic switching, while the 1.5KB Flash holds a complete speed-control state machine with ramp-up, ramp-down, and current-limit logic. Compared with discrete NE555 oscillators, the QT1MPE replaces several timing capacitors and a potentiometer with software-configurable duty cycle, and the 128-byte RAM is ample for the few state variables a 1-quadrant chopper needs. Note: 8-pin PDIP through-hole is convenient for hand-soldered hobby and educational projects, and 2.7-5.5V operation suits direct 3.3V or 5V motor rails.
Recommended
Simple LED Lighting Controllers
Driving single- or multi-channel LED strings is a strong fit for the MC68HC908QT1MPE because timing can be done entirely from the on-chip PWM without external drivers. With 5 I/O pins and 1.5KB Flash, the part can support 2-3 independent PWM channels for RGB color mixing plus a low-side enable FET, all sequenced from the internal 8MHz bus. The integrated LVD protects battery-powered LED fixtures from brown-out, and the 8-pin PDIP form factor keeps the BOM compact and inexpensive for high-volume lighting SKUs. Compared with dedicated LED-driver ICs, the HC08 adds flexibility for proprietary dimming curves and breath/blink patterns in firmware.
Recommended
Remote Control and RF Keyfob Transmitters
Battery-powered keyfob transmitters are an ideal use case for the MC68HC908QT1MPE: 8-pin PDIP is small and inexpensive, the 1.5KB Flash easily holds rolling-code or fixed-code transmit state machines, and the 2.7V minimum supply accepts single-cell Li-ion or 3V coin-cell batteries directly. The HC08's POR and LVD blocks ensure clean reset behavior on weak batteries, and PTA1-3 can bit-bang a sub-GHz OOK/FSK transmitter IC like the MC68HC908RF2 reference design. Compared with dedicated encoder ICs, the HC08 adds cryptographic flexibility and over-the-air update paths if Flash size permits.
Recommended
Industrial Sensor Signal Conditioning
In noisy industrial environments the MC68HC908QT1MPE can host digital-filter and threshold-detection logic around a simple sensor front-end. With 5 I/O pins, the part can read a digital sensor input, debounce in software, drive an alert LED, and switch a solid-state relay - all inside a single 8-pin PDIP that drops onto a small sensor-PCB footprint. The LVD and POR features are useful in industrial power rails (24V stepped down) where brown-out must not latch the MCU into an undefined state. Designers should note: there is no on-chip ADC on the QT1 variant, so any analog conditioning must be done with external op-amps or by stepping up to the QY1/QY4 variants.
Recommended
Battery-Powered Handheld Devices
The MC68HC908QT1MPE suits ultra-low-cost battery-powered devices such as thermometers, counter-timers, and pocket toys where 8-bit horsepower is more than enough. The internal trimmable oscillator eliminates the external crystal, the 2.7-5.5V range accepts 3V coin cells or 4.5V battery packs, and the 1.5KB Flash holds a typical firmware image without external memory. The 8-pin PDIP simplifies hand-soldered prototypes and through-hole production runs versus QFN-only modern MCUs. Trade-off: there is no low-power stop mode deeper than HC08's WAIT instruction, so designers targeting years-long coin-cell life should evaluate the S08 QG family for ~1 uA deep-sleep currents.
Recommended
Educational and Hobbyist Projects
Teaching and hobby communities have used the MC68HC908QT1MPE for years because the 8-pin PDIP is hand-solderable, the HC08 instruction set is small enough to be taught in one semester, and the on-chip PWM, timers, and POR give students realistic peripheral exposure. The 1.5KB Flash is a deliberate constraint that teaches good code-size discipline, and the BDM debug interface (using PTA0/PTA2) gives inexpensive in-circuit programming via a P&E USB-ML-ICSP or similar. Compared with the popular Arduino Uno's ATmega328P, the HC08 has fewer peripherals but a more deterministic instruction pipeline that maps cleanly to single-step teaching.
Recommended
Recommended Products Summary
Engineering reference data for MC68HC908QT1MPE — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC68HC908QT2MPE | MC68HC908QT4MPE | MC68HC908QY1MPE | MC9S08QG8CPE |
|---|---|---|---|---|---|
| Package | 8-PDIP | 8-PDIP - same | 8-PDIP - same | 8-PDIP - same | 8-PDIP - same |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Core | HC08 (8-bit) | HC08 (8-bit) | HC08 (8-bit) | HC08 (8-bit) | S08 (8-bit) |
| Flash Memory | 1.5 KB | 2 KB | 4 KB | 1.5 KB | 8 KB |
| RAM | 128 B | 128 B | 128 B | 128 B | 512 B |
| Maximum Clock | 8 MHz | 8 MHz | 8 MHz | 8 MHz | 20 MHz |
| I/O Pins | 5 | 5 | 5 | 5 | 5 |
| ADC | None | None | None | 10-bit, 4 channels | 10-bit, 8 channels |
| Supply Voltage | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 1.8 V to 3.6 V |
Key Differentiators
- Smallest 8-pin PDIP HC08 Flash part with 5 I/O and PWM (vs PIC12F509)
- Pin-compatible Flash-upgrade path without PCB change (vs MC68HC908QT4MPE)
- On-chip PWM and LVD in a 1.5K Flash part (vs MC9S08QG8CPE)
Design Notes
The MC68HC908QT1MPE draws supply current proportional to bus frequency and bus activity. Estimated: at 5V and 8MHz bus clock the typical run current is about 5 mA; with heavy PWM output drive the I/O pins add another 10-15 mA total. For battery-powered designs, drop the bus clock to 1 MHz internal and use the WAIT instruction between I/O events - the LVD threshold (typically 2.5V for 5V operation) lets the firmware enter a safe shutdown rather than executing from a brown-out supply. Add a 100 nF decoupling capacitor as close as possible between pins 3 (VDD) and 4 (VSS); a bulk 1-10 uF is optional but recommended if the supply is shared with motors or relays.
The 8-pin PDIP footprint is 0.300 inch (7.62 mm) row spacing and accepts standard 0.1 inch headers. Decoupling should be on the same side of the PCB as the MCU within 50 mil of the supply pins. Leave a clean ground pour under the MCU and avoid routing the BDM pair (PTA0/PTA2) past noisy traces - this 2-wire debug interface toggles at MCU clock speed and easily couples into adjacent signals. If the application uses the PWM module, route the PWM output trace over a contiguous ground pour and add a 100 ohm series resistor close to the pin if the trace exceeds 25 mm.
Three pitfalls to avoid on first-pass designs: (1) The QT1 variant has NO ADC - do not use it where analog signals must be read; choose QY1 or QY4 instead. (2) The RST pin is bidirectional - if your design uses an external supervisor, drive RST through a 1 kohm resistor to prevent contention during power-up. (3) The BGM debug interface shares PTA0 and PTA2 - if your application drives these as outputs, ensure the firmware immediately releases them after reset so a debug probe can attach. Also be aware that NXP has marked the part as Last Time Buy, so production planning must include a migration path to QT4 or S08.
Compliance Information
RoHS and REACH compliant per NXP product page (lead-free 8-PDIP marked with 'Pb-free' date code); not qualified for AEC-Q100 - not for new automotive designs; conflict-minerals declaration compliant per NXP corporate policy.
