MC68HC908QT4CP - 8MHz 8-bit HC08 MCU 4KB FLASH 8-PDIP | NXP
MPN: MC68HC908QT4CP ✗ Cuối đờiMC68HC908QT4CP Tóm tắt
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, memory, and peripherals onto one silicon die. The HC08 family is a low-cost, high-performance extension of the M68HC05 line, implementing a Complex Instruction Set Computer (CISC) with a Von Neumann memory map (a single shared address space for program and data, simplifying pointer-based access). MCUs like the MC68HC908QT4CP occupy the bottom tier of embedded computing - below 32-bit microcontrollers and microprocessors, but above discrete logic - and are used where deterministic I/O control, low power, and small footprint are more important than raw throughput.
Key features of the MC68HC908QT4CP include 4KB (4K x 8) of on-chip FLASH for program storage, 128 x 8 bytes of RAM, an internal ADC for sensor interface, a PWM channel for motor or LED control, and a Low-Voltage Detection (LVD) plus Power-On Reset (POR) for robust supply supervision. The 5 general-purpose I/O pins are software-configurable for pull-up, direction, and interrupt-on-edge. The CPU08 core provides 16-bit index register, 16-bit stack pointer, and BCD arithmetic instructions that simplify decimal handling in metering and panel applications.
The part operates from a 3V supply (typical 3.0V to 5.5V range per the family datasheet), supports in-circuit programming through the monitor ROM, and uses a FLASH page-erase architecture that allows at least 1000 program/erase cycles. The 8-pin PDIP package is the most user-friendly variant for breadboarding and through-hole hobbyist designs, while a surface-mount SO-8 variant exists in the same family.
Typical applications for the MC68HC908QT4CP include low-cost consumer appliances, IR remote-control transmitters, simple motor/LED controllers, white-goods user interfaces, and battery-powered sensor nodes where the small 8-pin footprint and on-chip ADC reduce BOM cost. According to the NXP MC68HC908QY4 family datasheet, the QT/QY sub-family targets cost-sensitive applications that need ADC, PWM, and FLASH in 8- or 16-pin packages.
When using this MCU, ensure the supply decoupling is adequate (typically 100nF plus 10uF bulk at VDD/VSS) and that the analog supply (AVDD/AVSS, where present on larger-pin-count siblings) is properly filtered if the ADC is used. FLASH write/erase operations require the supply to remain above the LVD threshold, and the monitor mode entry sequence (PTB3/PTB4 handshake on larger siblings, or PTA0 on this 8-pin device) must be respected when using in-system programming.
This page synthesizes distributor pricing, drop-in same-family alternatives (MC68HC908QT2CP, MC68HC908QT1CP), and practical design notes that go beyond the manufacturer datasheet alone.
Bộ thay thế dễ dàng lắp đặt cho MC68HC908QT4CP — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với MC68HC908QT4CP (cùng hình factor và footprint) — khác nhau ở Mounting Type, Program Memory Size, RAM Size.
MC68HC908QT4CPE
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MC68HC908QT2CP
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →MC68HC908QT1CP
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MC68HC908QY4CP
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MC9S08SH4CP
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MC68HC908QT4CP Tỷ lệ tối đa & tính chất điện
| Core Processor | HC08 |
| Core Size | 8-Bit |
| Maximum Clock Speed | 8 MHz |
| Program Memory Size | 4 KB (4K x 8) FLASH |
| RAM Size | 128 x 8 bytes |
| EEPROM Size | None |
| Number of I/O Pins | 5 |
| On-chip Peripherals | LVD, POR, PWM, ADC |
| Connectivity | Single-wire monitor / ICP |
| Architecture | Von Neumann (CISC) |
| Hộp | 8-PDIP (DIP-8) |
| Kiểu lắp đặt | Through-Hole |
| FLASH Endurance | >=1000 program/erase cycles (family spec) |
| Part Status | Obsolete (per distributor listing) |
Cấu hình chân MC68HC908QT4CP
| Chân 1 | PTA0/IRQ — Port A bit 0; also monitor-mode entry request (IRQ) |
| Chân 2 | PTA1 — Port A bit 1; GPIO / ADC channel |
| Chân 3 | PTA2 — Port A bit 2; GPIO / ADC channel |
| Chân 4 | PTA3 — Port A bit 3; GPIO / ADC channel |
| Chân 5 | PTA4 — Port A bit 4; GPIO / ADC channel |
| Chân 6 | PTA5 — Port A bit 5; GPIO / PWM output / ADC channel |
| Chân 7 | VSS — Ground reference |
| Chân 8 | VDD — Positive supply (3.0V to 5.5V family-typical) |
Ứng dụng tiêu biểu
MC68HC908QT4CP phù hợp cho 6 Áp dụngs: IR Remote Control Transmitter, Battery-Powered Sensor Node, White-Goods User Interface, LED Dimmer / PWM Controller, Simple Fan or Pump Controller, Educational / Hobby 8-bit Platform.
IR Remote Control Transmitter
The MC68HC908QT4CP is well suited to low-cost IR remote control transmitters where its 8-pin PDIP footprint, 5 GPIO, on-chip PWM, and HC08 core provide all required peripherals. The 8MHz CPU08 core runs a carrier-generation interrupt service routine that drives the PWM output at typically 38 kHz with sub-carrier duty cycle, while the small 4KB FLASH budget is sufficient for protocol state machines (RC5, NEC, SIRC). The on-chip LVD prevents under-voltage transmission glitches when battery droops below 2.7V.
Được đề xuất
Battery-Powered Sensor Node
In a battery-powered sensor node, the MC68HC908QT4CP's 5 GPIO with wake-on-edge, on-chip ADC for sensor reading, and HC08 STOP/WAIT low-power modes minimize quiescent current. The 128-byte RAM is enough to buffer a single sensor sample plus protocol header, and the 4KB FLASH holds a tiny MAC layer plus application code. With the LVD configured for brown-out, the MCU safely supervises a 3V coin cell through end-of-life.
Được đề xuất
White-Goods User Interface
The MC68HC908QT4CP's PWM drives a buzzer or LED backlight, while its 5 GPIO scan a small keypad matrix or capacitive touch pad in a washing machine or microwave user interface. The 8-pin PDIP form factor is through-hole friendly for low-volume white-goods modules, and the HC08 core's BCD arithmetic simplifies timer-display handling. The 4KB FLASH comfortably holds menu and beep-pattern libraries.
Được đề xuất
LED Dimmer / PWM Controller
For single-channel LED dimming or motor-speed control, the MC68HC908QT4CP provides a hardware PWM channel that can drive a logic-level MOSFET gate directly, freeing the CPU for user-input handling. The HC08 core updates duty cycle from a potentiometer read through the on-chip ADC, and the 8MHz clock gives 8-bit PWM resolution at 31 kHz - above the audible band. The 5 GPIO handle the potentiometer, mode button, status LED, and MOSFET drive.
Được đề xuất
Simple Fan or Pump Controller
In a low-cost 12V DC fan or small pump controller, the MC68HC908QT4CP reads an NTC thermistor through its ADC and adjusts PWM drive to maintain a temperature setpoint. The 4KB FLASH holds a simple PID loop, and the LVD protects the firmware from corrupted state during cold-crank voltage drops. The 8-pin PDIP is well suited to through-hole assembly for compact appliance modules.
Được đề xuất
Educational / Hobby 8-bit Platform
The MC68HC908QT4CP is widely used in university embedded-systems courses and hobbyist projects because of its breadboard-friendly 8-pin PDIP, classic HC08 architecture that teaches CISC concepts, and free development tools (CodeWarrior HC08, P&E Multilink). The 4KB FLASH and 128 B RAM are tight but realistic constraints that teach memory-conscious firmware design. The 5 GPIO drive LEDs, buttons, and a serial UART bit-banged through PTA0/PTA1.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho MC68HC908QT4CP — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | MC68HC908QT4CPE | MC68HC908QT2CP | MC68HC908QT1CP | MC68HC908QY4CP | MC9S08SH4CP |
|---|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 8-PDIP (DIP-8) | 8-PDIP (DIP-8) - same | 8-PDIP (DIP-8) - same | 8-PDIP (DIP-8) - same | 16-PDIP (DIP-16) | 8-PDIP (DIP-8) - same |
| Core | HC08 (CPU08) | HC08 (CPU08) | HC08 (CPU08) | HC08 (CPU08) | HC08 (CPU08) | S08 (forward-migration) |
| Clock Speed | 8 MHz | 8 MHz | 8 MHz | 8 MHz | 8 MHz | 20 MHz (S08) |
| FLASH Program Memory | 4 KB | 4 KB | 2 KB | 1 KB | 4 KB | 4 KB |
| RAM Size | 128 B | 128 B | 128 B | 128 B | 128 B | 256 B |
| GPIO Pins | 5 | 5 | 5 | 5 | 13 | 5 |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete | Active (recommended migration) |
Bảo phân biệt quan trọng
- Largest FLASH in 8-pin PDIP HC08 line (vsMC68HC908QT1CP)
- Through-hole PDIP form factor (vsMC9S08SH4CP)
- Native 5 GPIO with on-chip ADC and PWM (vsMC68HC908QY4CP)
- On-chip FLASH with in-circuit programming (vsOlder OTP MCUs)
Ghi chú thiết kế
Estimated: at 8MHz bus clock and 5V supply, the HC08 core draws approximately 5 to 10 mA active and <10 uA in STOP mode. Decouple VDD/VSS with a 100nF ceramic capacitor placed within 5 mm of the pins, plus a 10 uF bulk capacitor on the supply rail. The LVD threshold should be set above the minimum operating voltage (3.0V family-typical) so that firmware cannot write to FLASH under-voltage and corrupt the program image.
The PTA0/IRQ pin doubles as the monitor-mode entry request line. If your application pulls PTA0 high at power-up, the MCU will enter monitor mode instead of running user code. Use a weak pull-up on PTA0 or leave it undriven at reset, or include a 100 ms delay before driving PTA0 to allow user code to start and clear the monitor flag.
For the 8-pin PDIP footprint, use a standard 0.300 inch / 7.62 mm row spacing and 2.54 mm / 0.100 inch pin pitch. Place the decoupling capacitor between VDD (pin 8) and VSS (pin 7) with the shortest possible trace length. For ADC accuracy, route analog inputs PTA1-PTA5 away from the PWM output (PTA5) and keep a ground pour under the analog traces.
When using the on-chip ADC, run an acquisition cycle of at least 16 ADC clocks and avoid switching the PTA5 PWM output during ADC sampling. Internal channel-to-channel crosstalk is typically <1 LSB but can rise if digital outputs toggle simultaneously. Average 4 to 16 samples in firmware for sensor-reading noise reduction below the 10-bit raw resolution.
At 8MHz and 5V the HC08 core dissipates well under 100 mW, so no heatsink is required. Industrial-temperature variants (e.g. MC68HC908QT4CPE) operate from -40C to +85C junction. In sealed enclosures, derate ambient temperature by 10C to account for self-heating from nearby power components.
Thông tin tuân thủ
Part is marked obsolete by NXP; full compliance certificates may not be available for older 8-PDIP lots. Lead-free and RoHS status not explicitly stated in provided data - mark unknown.
