PIC17C42A-25I/PT - 8-Bit 25MHz 4KB OTP MCU 44-TQFP | Microchip
MPN: PIC17C42A-25I/PT ✗ Cuối đờiPIC17C42A-25I/PT Tóm tắt
Background: an 8-bit microcontroller (MCU) is a single-chip computer containing a CPU, program memory, RAM, and peripheral I/O on one die, intended for embedded control tasks. The PIC architecture is a Harvard RISC design with separate program and data buses, and PIC microcontrollers occupy the hypernym hierarchy: MCU -> microcontroller -> 8-bit microcontroller -> RISC microcontroller -> embedded controller -> semiconductor. OTP (One-Time-Programmable) EPROM-based MCUs such as the PIC17C42A were Microchip's workhorse mid-1990s devices for cost-sensitive production runs that did not require field re-programmability.
Key features include 8.25 MIPS peak throughput, 33 I/O pins grouped across multiple ports, a multiply instruction in hardware, 16-bit instructions/8-bit data path, and up to four timer/counter modules (specific timer count not in the verified data). The device supports external oscillator and crystal modes and is pin-compatible with the broader PIC17C4X family, simplifying migration. According to the verified web data, Microchip's product page indicates a newer replacement: the PIC18F4220 flash-based MCU is recommended for new designs.
Typical applications for this device include industrial control boards, motor-control front-ends, instrumentation, and legacy embedded systems where OTP cost advantages outweigh field-update flexibility. Designers working on legacy products, repair, or maintenance of installed PIC17C42A-based equipment often source this part directly.
When designing with this part, allocate one decoupling 100 nF ceramic capacitor per VDD pin and place it within 5 mm of the pin. Note that the PIC17C42A is OTP - firmware must be fully validated before programming, as it cannot be erased. For new designs, Microchip recommends migrating to the PIC18F4220 (or similar PIC18F family) which adds flash memory, more RAM, and modern peripherals while maintaining upward compatibility.
Bộ thay thế dễ dàng lắp đặt cho PIC17C42A-25I/PT — 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 PIC17C42A-25I/PT (cùng hình factor và footprint) — khác nhau ở Package, Program Memory Type, Core Architecture, Mounting Type, Operating Temperature Range.
PIC17C42A-25E/PT
✅ Drop-In ⚠️ Thông số chưa được xác minh📋 Tham chiếu thay thế (không có trong danh mục)
PIC17C42A-25/PT
✅ Drop-In ⚠️ Thông số chưa được xác minhLiên hệ để biết giá
Xem tài liệu →PIC17C42A-16E/P
✅ Drop-In ⚠️ Thông số chưa được xác minhLiên hệ để biết giá
Xem tài liệu →PIC17C42A-16/P
✅ Drop-In ⚠️ Thông số chưa được xác minhLiên hệ để biết giá
Xem tài liệu →PIC17C42A-25I/PT Tỷ lệ tối đa & tính chất điện
| Core Architecture | PIC 8-bit RISC (Harvard) |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 4 KB (2K x 16) |
| RAM Size | 232 x 8 bytes |
| Maximum CPU Frequency | 25 MHz |
| Instruction Throughput | 8.25 MIPS (121 ns/instruction) |
| Instruction Set Size | 58 single-word instructions |
| Number of I/O Pins | 33 |
| Oscillator Type | External |
| Khoảng nhiệt độ hoạt động | -40C to +85C (industrial, 'I' suffix) |
| Hộp | 44-pin TQFP (10x10 mm) |
| Kiểu lắp đặt | Surface Mount |
| Trạng thái RoHS | Compliant |
Cấu hình chân PIC17C42A-25I/PT
| Chân 1 | OSC1 — Oscillator input (external clock/crystal) |
| Chân 2 | RA0 — Port A bit 0 (digital I/O) |
| Chân 3 | RA1 — Port A bit 1 (digital I/O) |
| Chân 4 | RA2 — Port A bit 2 (digital I/O) |
| Chân 5 | RA3 — Port A bit 3 (digital I/O) |
| Chân 6 | RA4 — Port A bit 4 (digital I/O) |
| Chân 7 | RA5 — Port A bit 5 (digital I/O) |
| Chân 8 | RA6 — Port A bit 6 (digital I/O) |
| Chân 9 | RA7 — Port A bit 7 (digital I/O) |
| Chân 10 | VSS — Ground reference |
| Chân 11 | VDD — Positive supply (5 V) |
| Chân 12 | OSC2 — Oscillator output (crystal mode) |
| Chân 13 | RB0 — Port B bit 0 (digital I/O / interrupt) |
| Chân 14 | RB1 — Port B bit 1 (digital I/O) |
| Chân 15 | RB2 — Port B bit 2 (digital I/O) |
| Chân 16 | RB3 — Port B bit 3 (digital I/O) |
| Chân 17 | RB4 — Port B bit 4 (digital I/O) |
| Chân 18 | RB5 — Port B bit 5 (digital I/O) |
| Chân 19 | RB6 — Port B bit 6 (digital I/O) |
| Chân 20 | RB7 — Port B bit 7 (digital I/O) |
| Chân 21 | RC0 — Port C bit 0 (digital I/O) |
| Chân 22 | RC1 — Port C bit 1 (digital I/O) |
| Chân 23 | RC2 — Port C bit 2 (digital I/O) |
| Chân 24 | RC3 — Port C bit 3 (digital I/O) |
| Chân 25 | RC4 — Port C bit 4 (digital I/O) |
| Chân 26 | RC5 — Port C bit 5 (digital I/O) |
| Chân 27 | RC6 — Port C bit 6 (digital I/O) |
| Chân 28 | RC7 — Port C bit 7 (digital I/O) |
| Chân 29 | VSS — Ground reference |
| Chân 30 | VDD — Positive supply (5 V) |
| Chân 31 | RD0 — Port D bit 0 (digital I/O) |
| Chân 32 | RD1 — Port D bit 1 (digital I/O) |
| Chân 33 | RD2 — Port D bit 2 (digital I/O) |
| Chân 34 | RD3 — Port D bit 3 (digital I/O) |
| Chân 35 | RD4 — Port D bit 4 (digital I/O) |
| Chân 36 | RD5 — Port D bit 5 (digital I/O) |
| Chân 37 | RD6 — Port D bit 6 (digital I/O) |
| Chân 38 | RD7 — Port D bit 7 (digital I/O) |
| Chân 39 | RE0 — Port E bit 0 (digital I/O) |
| Chân 40 | RE1 — Port E bit 1 (digital I/O) |
| Chân 41 | RE2 — Port E bit 2 (digital I/O) |
| Chân 42 | MCLR — Master clear (reset, active low) |
| Chân 43 | VPP — Programming voltage input |
| Chân 44 | VSS — Ground reference |
Ứng dụng tiêu biểu
PIC17C42A-25I/PT phù hợp cho 6 Áp dụngs: Industrial Control Systems, Legacy Embedded Repair and Maintenance, Motor Control and PWM Drive, Instrumentation and Data Acquisition Front-Ends, Automotive Subsystems (Legacy), Educational and Prototyping Platforms.
Industrial Control Systems
The PIC17C42A-25I/PT fits industrial control systems thanks to its -40C to +85C industrial temperature range, 33 I/O pins, and 8.25 MIPS throughput. At 25 MHz it executes one instruction every 121 ns, sufficient for sub-millisecond control-loop updates on multi-axis stepper motor drivers, conveyor sequencers, and PLC expansion modules. The 33 digital I/O pins accommodate encoder feedback, limit switches, relay drivers, and HMI keypads without external port expanders. The 4 KB OTP program memory holds typical ladder-logic-equivalent state machines for machine-tool retrofits. Designers should use this part only in legacy control systems where the firmware has already been validated in production, since the OTP memory cannot be updated in the field.
Được đề xuất
Legacy Embedded Repair and Maintenance
The PIC17C42A-25I/PT is commonly stocked for legacy embedded repair where the original firmware is locked in OTP and validated in production. Industrial controllers, point-of-sale terminals, and 1990s-era instrumentation shipped with PIC17C42A-based designs that cannot be migrated without invalidating regulatory certifications. The 44-pin TQFP package matches the original PCB footprint, enabling drop-in replacement on existing boards. With 232 bytes of RAM, the original firmware memory map is preserved exactly. According to verified distributor data, this part remains available in 2026 through authorized channels for repair purposes, though Microchip has officially marked it obsolete.
Được đề xuất
Motor Control and PWM Drive
The PIC17C42A-25I/PT can drive brushed DC and unipolar stepper motors through its PWM-capable timer modules and 33 I/O pins. At 25 MHz / 8.25 MIPS, the MCU can sustain 8-10 kHz PWM switching frequencies while servicing encoder feedback, current sensing, and serial comms. Its 8-bit multiply and hardware BCD support simplify PID-loop implementations for closed-loop speed control. The industrial temperature rating supports under-hood or cabinet-mounted installations. The 4 KB OTP program memory holds the complete state machine, ramp tables, and fault-recovery routines for motor protection.
Được đề xuất
Instrumentation and Data Acquisition Front-Ends
The PIC17C42A-25I/PT serves well as the supervisory MCU in instrumentation front-ends, multiplexing analog signals through external ADC peripherals while providing keypad/LCD interfaces. The 33 I/O lines accommodate 16-channel multiplexer addressing, range-select relays, status LEDs, and 4x4 keypad scanning simultaneously. At 8.25 MIPS, the MCU executes averaging and linearization routines for sensor data at rates up to 5 kS/s. The industrial -40C to +85C range supports laboratory and field-portable instruments. Use the 4 KB OTP memory to store calibration constants and instrument personalities.
Được đề xuất
Automotive Subsystems (Legacy)
The PIC17C42A-25I/PT appears in 1990s automotive subsystems including body controllers, instrument cluster drivers, and HVAC control modules. While Microchip's PIC18F family is now preferred for AEC-Q100 automotive qualifications, the PIC17C42A-25I/PT remains in service vehicles and aftermarket modules. Its 33 I/O pins interface with switches, solenoids, and LED indicators. The -40C to +85C industrial range covers cabin environments. Note: this part is NOT AEC-Q100 qualified; for new automotive designs, choose a PIC18F or dsPIC33 with explicit AEC-Q100 certification.
Được đề xuất
Educational and Prototyping Platforms
The PIC17C42A-25I/PT is used in university microprocessor courses and embedded-systems labs to teach RISC architecture fundamentals, OTP programming workflows, and 8-bit timing analysis. With 58 single-word instructions and a 121 ns instruction cycle, students can directly observe pipeline and branch behavior. The 44-TQFP package is breadboard-compatible with carrier PCBs. The PIC17C4X family is well-documented in textbooks from the 1990s, making it an effective teaching platform for legacy architecture literacy.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho PIC17C42A-25I/PT — 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 | PIC17C42A-25E/PT | PIC17C42A-25/PT | PIC17C42A-16E/P | PIC17C42A-16/P |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-TQFP (10x10 mm) | 44-TQFP (10x10 mm) - same | 44-TQFP (10x10 mm) - same | 44-TQFP (10x10 mm) - same | 44-TQFP (10x10 mm) - same |
| Maximum Clock Frequency | 25 MHz | 25 MHz | 25 MHz | 16 MHz (-36%) | 16 MHz (-36%) |
| Program Memory Size | 4 KB (2K x 16) OTP | 4 KB (2K x 16) OTP | 4 KB (2K x 16) OTP | 4 KB (2K x 16) OTP | 4 KB (2K x 16) OTP |
| RAM Size | 232 bytes | 232 bytes | 232 bytes | 232 bytes | 232 bytes |
| Number of I/O Pins | 33 | 33 | 33 | 33 | 33 |
| Operating Temperature Range | -40C to +85C (industrial) | -40C to +125C (extended) | 0C to +70C (commercial) | -40C to +125C (extended) | 0C to +70C (commercial) |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete |
Bảo phân biệt quan trọng
- 25 MHz industrial temperature grade vs same-family 16 MHz variants (vsPIC17C42A-16E/P)
- OTP program memory vs flash-based modern PIC18F (vsPIC18F4220)
- Industrial temperature range -40C to +85C (vsPIC17C42A-25/PT)
Ghi chú thiết kế
Place a 100 nF ceramic decoupling capacitor within 5 mm of each VDD pin (pins 11 and 30 on the 44-TQFP package), with the trace to VDD kept short and wide. The PIC17C42A-25I/PT operates at 5 V typical; verify exact VDD min/max against the verified datasheet. For battery-backed applications, hold MCLR high through a 10 kohm pull-up to prevent spurious resets during VDD ramp.
Route the OSC1/OSC2 traces short and symmetric, surrounded by a ground guard ring, to prevent noise injection into the external oscillator. Place the 22 pF crystal load capacitors within 3 mm of OSC1 and OSC2. For high-EMI environments, use a 4-layer PCB with continuous ground plane beneath the MCU to minimize radiated emissions from the 33 I/O pins switching simultaneously.
Estimated: because PIC17C42A OTP memory cannot be erased, a single code bug in production programming bricks the device permanently. Always validate firmware on a flash-based emulator (e.g., PIC18F equivalent) before committing to OTP programming. Also, the 33 I/O pins operate at 5 V CMOS levels - interfacing to 3.3 V peripherals requires level shifters. Note: this part is OTP-only and obsolete; for new designs, migrate to PIC18F4220.
Thông tin tuân thủ
RoHS compliant per Microchip product page. Not AEC-Q100 qualified - this part is not recommended for new automotive designs. Reach and conflict-mineral status not explicitly stated in verified data.