MCHC705JJ7CPE - 8-bit HC05 MCU, 6KB OTP, 2.1MHz, DIP-20 | NXP
MPN： MCHC705JJ7CPE ✗ 停產MCHC705JJ7CPE 概覽
An 8-bit microcontroller (MCU) is a single-chip computer built around an 8-bit data path, on-chip program memory, RAM, peripherals, and I/O. It belongs to the broader hierarchy: microcontroller -> embedded processor -> semiconductor -> electronic component. The HC05 line from NXP/Freescale is one of the longest-lived 8-bit families, designed for deterministic, low-power control tasks that do not need the throughput of a 16- or 32-bit core. Compared with modern ARM Cortex-M0 parts, HC05 MCUs trade raw performance for simplicity, an easy-to-write instruction set, and a small memory footprint that fits mass-market appliance and consumer applications.
Key features of the MCHC705JJ7CPE include 6KB (6144 bytes) of OTP program memory, 224 bytes of on-chip RAM, 14 general-purpose I/O lines, an internal oscillator that removes the need for an external crystal on many designs, a serial communications interface (SCI) for UART-style asynchronous serial, a 16-bit timer with capture and compare, and a five-channel 8-bit ADC. The on-chip monitor ROM provides in-circuit serial programming for development and field updates. The 'C' temperature grade supports 0C to +70C operation, while the 'E' suffix denotes the -40C to +125C extended grade - a key discriminator when selecting between suffixes in the family.
The device uses the legacy HC05 core with a von Neumann memory map. The OTP memory is one-time programmable, so firmware must be fully verified before production programming; for high-volume runs, the masked-ROM equivalent (MCHC705JJ7MPE or similar) is more economical. The internal oscillator and the absence of an external bus make the device suitable for single-chip-mode applications where the MCU is the only active logic on the board.
Typical applications include white-goods motor drivers, small appliance controllers, simple sensor interfaces, security and alarm panels, remote-control transmitters, and educational/development boards where a through-hole DIP package aids manual soldering and lab rework. Designers should note that OTP memory cannot be re-programmed, so a debug-and-reflash workflow typically uses the windowed or EPROM-emulator sibling (MCHC705JJ7PBE) during development, with the OTP device reserved for production.
When designing with the MCHC705JJ7CPE, ensure adequate decoupling on VDD/VSS (typically 100 nF plus bulk), keep the RESET pin high through a pull-up with optional capacitor for POR, and verify that the chosen I/O lines are 5V-tolerant when interfacing 3.3V peripherals. Trade-off: the 2.1 MHz clock caps instruction throughput but minimizes EMI and power consumption versus faster HC08/HC11 derivatives.
This page synthesizes distributor pricing, OTP-versus-mask trade-offs, and practical design notes not found in the legacy NXP datasheet alone.
直接替換替代品，適用於 MCHC705JJ7CPE — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： MCHC705JJ7CPE （相同外形與佔位） — 差異在於 Operating Temperature, Package, Timers.
MCHC705JJ7PBE
✅ 直接替換📋 參考替代品（不在目錄中）
MCHC705JJ7MPE
✅ 直接替換📋 參考替代品（不在目錄中）
MC68HC705J1A
✅ 直接替換📋 參考替代品（不在目錄中）
MC68HC705C8A
✅ 直接替換📋 參考替代品（不在目錄中）
AT89C2051-24PU
✅ 直接替換📋 參考替代品（不在目錄中）
MCHC705JJ7CPE 最大額定值與電氣特性
| Core | HC05 8-bit |
| Program Memory Size | 6 KB (6K x 8) OTP |
| RAM Size | 224 bytes |
| 最大時脈頻率 | 2.1 MHz |
| Number of I/O Pins | 14 |
| 封裝 | 20-DIP (0.300", 7.62 mm) |
| 安裝類型 | Through-Hole (THT) |
| ADC | 5-channel, 8-bit (per family datasheet) |
| Timers | 1 x 16-bit with capture/compare |
| Serial Interface | SCI (UART) |
| 工作溫度 | 0C to +70C (C grade) |
| Program Memory Type | One-Time Programmable (OTP) |
| On-chip Monitor ROM | Yes (in-circuit serial programming) |
| Internal Oscillator | Yes (typical of HC05 'JJ' family) |
MCHC705JJ7CPE 腳位配置
| 腳位 1 | IRQ — External interrupt request input (active low) |
| 腳位 2 | VSS — Ground reference |
| 腳位 3 | TCMP — Timer compare output |
| 腳位 4 | PA0 — Port A bit 0 (digital I/O) |
| 腳位 5 | PA1 — Port A bit 1 (digital I/O) |
| 腳位 6 | PA2 — Port A bit 2 (digital I/O) |
| 腳位 7 | PA3 — Port A bit 3 (digital I/O) |
| 腳位 8 | PA5 — Port A bit 5 (digital I/O / SCI RxD) |
| 腳位 9 | PA6 — Port A bit 6 (digital I/O / SCI TxD) |
| 腳位 10 | PA7 — Port A bit 7 (digital I/O) |
| 腳位 11 | PB0 — Port B bit 0 (digital I/O / ADC) |
| 腳位 12 | PB1 — Port B bit 1 (digital I/O / ADC) |
| 腳位 13 | PB2 — Port B bit 2 (digital I/O / ADC) |
| 腳位 14 | PB3 — Port B bit 3 (digital I/O / ADC) |
| 腳位 15 | PB4 — Port B bit 4 (digital I/O / ADC) |
| 腳位 16 | VDD — Positive supply (typically +5 V) |
| 腳位 17 | OSC1 — External clock input / crystal connection (internal osc also used) |
| 腳位 18 | OSC2 — Crystal connection / clock output (internal osc also used) |
| 腳位 19 | RESET — Active-low reset input with on-chip pull-up |
| 腳位 20 | TEST — Test mode pin (must be tied to VDD for normal operation) |
典型應用
MCHC705JJ7CPE 適用於 6 應用s: White Goods Motor Control, Small Appliance Controller, Sensor Interface Hub, Security and Alarm Panel, Remote Control Transmitter / Receiver, Educational and Development Boards.
White Goods Motor Control
The MCHC705JJ7CPE fits white-goods motor control because its HC05 core, 14 I/O lines, and 5-channel 8-bit ADC can read speed sensors and commutator feedback, while the 16-bit timer drives TRIAC or relay switching at line frequency. With 6KB OTP it holds typical appliance-state firmware (wash cycles, sensor debouncing, error latching) without external memory, and the 2.1 MHz clock is fast enough for sub-millisecond control loops but low enough to minimize EMI near mains wiring. Designers place the part in 20-DIP for through-hole reliability in washers and dryers; the on-chip oscillator removes the need for a ceramic resonator, saving BOM cost and board area on cost-engineered consumer appliances.
推薦
Small Appliance Controller
The MCHC705JJ7CPE serves as the central state machine in coffee makers, rice cookers, blenders, and similar small appliances. Its 6KB OTP comfortably stores menu/state tables, its 224-byte RAM handles sensor averaging buffers, and the SCI/UART block supports debug logging or wireless-module hookup for premium models. The HC05's well-known instruction set simplifies firmware porting from previous Freescale designs, and the 20-DIP package simplifies the manual rework typical in low-volume appliance SKUs. Operating temperature range of 0C to +70C covers the kitchen environment, while the active-low RESET with on-chip POR handles power-on in noisy mains conditions.
推薦
Sensor Interface Hub
The MCHC705JJ7CPE's 5-channel 8-bit ADC, 14 I/O pins, and HC05 core make it a sensible sensor interface hub for HVAC, security panels, and simple IoT edge nodes. The ADC multiplexes thermistor, humidity, and PIR-style sensor inputs; the 16-bit timer captures pulse-width-modulated sensor outputs; the SCI block uplinks readings to a host MCU or radio module. With only 2.1 MHz clock, the part draws low quiescent current, extending battery life in remote sensor nodes. The 20-DIP through-hole package suits field-serviceable panels where technicians may need to swap the MCU; the on-chip monitor ROM supports in-system firmware updates via the serial monitor.
推薦
Security and Alarm Panel
The MCHC705JJ7CPE runs the central scan loop in legacy security panels, polling 8-12 wired zones through its 14 I/O lines and driving the keypad, siren, and dialer outputs through buffered lines. Its deterministic HC05 core avoids jitter in zone scan timing - critical for false-alarm prevention - and the 6KB OTP holds zone-mapping tables plus dialer protocol stacks. The on-chip SCI talks to a modem IC for PSTN or GSM backup reporting. The 20-DIP package supports field replacement without specialized soldering tools, and the commercial 0C to +70C temperature grade covers indoor wall-mount installations in residential and light-commercial security markets.
推薦
Remote Control Transmitter / Receiver
The MCHC705JJ7CPE builds simple RF remote controls and receivers where the 6KB OTP stores key-mapping tables, rolling-code state, and modulation profiles. Its SCI drives a low-cost ASK/FSK transmitter IC, while the 16-bit timer generates carrier frequencies and bit-time precision for IR/RF protocols. With 2.1 MHz clock and aggressive idle modes, the part fits battery-powered transmitters that must last years on a coin cell. The 20-DIP package is friendly to hand-built and educational electronics labs, which is where this legacy HC05 family still sees significant volume. The HC05 toolchain (Motorola/Freescale/NXP assemblers and P&E Micro debug probes) remains available from legacy support channels.
推薦
Educational and Development Boards
The MCHC705JJ7CPE is widely used in legacy university curricula and Freescale/NXP training kits because of its straightforward HC05 instruction set, 20-DIP through-hole package (easy to socket), and on-chip monitor ROM that supports serial debug without a special bond-out part. Students learn timers, ADC scanning, and SCI communications on this device before moving up to HC08/HCS08 or ARM cores. The 6KB OTP is large enough to host complete lab exercises (LED scanners, keypad readers, PWM motor demos) without external memory. Replacement through-hole socketed variants (MCHC705JJ7PBE) let instructors re-flash boards class after class without chip replacement.
推薦
推薦產品摘要
工程參考資料，適用於 MCHC705JJ7CPE — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | MCHC705JJ7PBE | MCHC705JJ7MPE | MC68HC705J1A | MC68HC705C8A | AT89C2051-24PU |
|---|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | Microchip Technology |
| Package | 20-DIP (0.300", 7.62 mm) | 20-DIP windowed - same | 20-DIP - same | 20-DIP - same | 20-DIP / PLCC variants - same | 20-DIP (0.300") - same |
| Core | HC05 8-bit | HC05 8-bit | HC05 8-bit | HC05 8-bit | HC05 8-bit | 8051 8-bit (different ISA) |
| Program Memory | 6 KB OTP | 6 KB windowed EPROM | 6 KB mask ROM | 1.2 KB EPROM | 8 KB EPROM | 2 KB flash |
| RAM | 224 bytes | 224 bytes | 224 bytes | 64 bytes | 304 bytes | 128 bytes |
| Max Clock Frequency | 2.1 MHz | 2.1 MHz | 2.1 MHz | 4 MHz | 4 MHz | 24 MHz |
| I/O Pins | 14 | 14 | 14 | 14 | 20 | 15 |
| Program Memory Type | OTP | UV EPROM (erasable) | Mask ROM (locked) | EPROM | EPROM | Flash (reprogrammable) |
| Production Status (2026) | NRD (Not Recommended for New Designs) | NRD / EOL | NRD | NRD | NRD | Active |
主要差異化特點
- On-chip monitor ROM for serial in-circuit programming (對比AT89C2051-24PU)
- Larger code memory than the MC68HC705J1A cousin (對比MC68HC705J1A)
- Reprogrammable windowed EPROM sibling available (對比MC68HC705C8A)
設計說明
The MCHC705JJ7CPE operates from a single +5 V supply on VDD (pin 16). Place a 100 nF decoupling capacitor within 5 mm of the VDD pin and a bulk 10 uF capacitor on the supply rail close to the MCU. The HC05 internal POR and the external RESET pull-up (typically 4.7 kohm to VDD with a 0.1 uF cap) handle power-on. Note that at 2.1 MHz the part draws single-digit mA of active current, so decoupling alone is sufficient - no bulk capacitance beyond 10 uF is required.
Because the 20-DIP package is through-hole, place the MCU at the board edge or near a socket for easy replacement during development. Keep the RESET trace short and isolated from high-current traces (relay, TRIAC) to avoid false resets. If you use an external crystal on OSC1/OSC2, route the crystal traces short and symmetric with a ground guard ring; otherwise leave the internal oscillator selected and ground OSC2. The TEST pin must be tied to VDD; floating it can latch the device in test mode.
Common pitfalls with the MCHC705JJ7CPE: (1) OTP memory cannot be re-programmed - validate firmware on the MCHC705JJ7PBE windowed EPROM cousin before committing code; (2) the 'C' suffix denotes 0C to +70C commercial grade, not -40C to +125C - select the 'E' suffix for industrial; (3) the TEST/VPP pin MUST be tied to VDD or the part will not enter user mode; (4) the on-chip monitor ROM uses PA0/PA3 - reclaim these as general I/O only after disabling the monitor in the CONFIG register; (5) do not exceed 5.5 V on VDD or the EPROM/OTP cells can be corrupted during programming.
合規資訊
RoHS / lead-free status not stated in the verified distributor listings; this part pre-dates strict RoHS enforcement and is commonly shipped as SnPb (leaded) through-hole DIP. NXP/Freescale legacy MCUs follow the manufacturer's compliance matrix in the product datasheet; check there for the exact MCHC705JJ7CPE compliance statement. AEC-Q100 is not applicable to this commercial-grade 8-bit MCU.
