PIC17C42A-33/PQ - 33MHz 8-bit OTP MCU 4KB | Microchip
MPN: PIC17C42A-33/PQ ✗ Cuối đờiPIC17C42A-33/PQ Tóm tắt
Background knowledge - what is an 8-bit OTP microcontroller? An 8-bit MCU (microcontroller) is a single-chip computer with an 8-bit data path, integrating CPU, RAM, ROM/Flash/OTP program memory, and peripherals. OTP (One-Time-Programmable) program memory uses fusible-link or anti-fuse cells that can be written exactly once after manufacture - cheaper than Flash for low-to-medium volume production and ideal for stable, mature firmware. Within the broader taxonomy, the PIC17C42A belongs to: 8-bit MCU -> RISC microcontroller -> Harvard-architecture MCU -> PIC17C family -> CMOS OTP class, and is the predecessor family that influenced the modern PIC18F architecture.
Key features include 121 ns instruction cycle at 33 MHz (8.25 MIPS throughput), 4 KB OTP program memory, 232 x 8 RAM, 33 I/O lines, an external-oscillator interface, a USART serial port, and an 8-bit parallel slave port. The PIC17C42A (Rev. A) conforms functionally to the PIC17C4X preliminary datasheet (DS30412C). Microchip officially notes that a newer device is available - the PIC18F4220 - for new designs; the PIC17C42A remains in stock at franchised distributors but is recommended primarily for legacy maintenance and existing designs.
Technical depth: the PIC17C42A uses a 16-bit-wide instruction word stored in OTP, with a Harvard bus that lets the CPU fetch an instruction and read a data byte in the same cycle. The 58 single-word instruction set keeps code density high. The wide 40- or 44-pin package and 33 I/O lines make the part suitable for applications that need many parallel digital signals without an external bus expander.
Typical applications include industrial control boards, motor control front-ends, instrument front panels, embedded serial-control nodes, and legacy PIC16C5X/PIC12CXXX/PIC16CXX upgrades that need more I/O. This page synthesizes distributor pricing, drop-in alternatives, and design notes that the legacy datasheet alone does not compile.
Bộ thay thế dễ dàng lắp đặt cho PIC17C42A-33/PQ — 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-33/PQ (cùng hình factor và footprint) — khác nhau ở Package, Program Memory Type, Mounting Type, RAM Size, Core Architecture.
PIC17C42A-25/PQ
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →PIC17C42A-16/PQ
✅ Drop-In📋 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-25E/P
✅ 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-33/PQ Tỷ lệ tối đa & tính chất điện
| Device Family | PIC17C |
| Core Architecture | 8-bit RISC (Harvard) |
| Instruction Set Size | 58 single-word instructions |
| Program Memory Type | OTP (One-Time-Programmable) |
| Program Memory Size | 4 KB (2K x 16) |
| RAM Size | 232 x 8 bytes (232 B) |
| Maximum CPU Frequency | 33 MHz |
| Instruction Execution Time | 121 ns (8.25 MIPS) |
| Number of I/O Pins | 33 |
| Oscillator Type | External |
| Hộp | 44-pin MQFP (PQ) - Metric Quad Flat Pack |
| Kiểu lắp đặt | Surface Mount |
| Packaging | Tube |
| Peripherals | USART, Timers, Capture/Compare/PWM, 8-bit Parallel Slave Port |
Cấu hình chân PIC17C42A-33/PQ
| Chân 1 | RA0/AN0 — Port A bit 0 / analog input 0 |
| Chân 2 | RA1/AN1 — Port A bit 1 / analog input 1 |
| Chân 3 | RA2/AN2 — Port A bit 2 / analog input 2 |
| Chân 4 | RA3/AN3 — Port A bit 3 / analog input 3 |
| Chân 5 | RA4/AN4 — Port A bit 4 / analog input 4 |
| Chân 6 | RA5/AN5 — Port A bit 5 / analog input 5 |
| Chân 7 | OSC1 — External oscillator input |
| Chân 8 | OSC2 — External oscillator output |
| Chân 9 | MCLR/VPP — Master clear reset / programming voltage |
| Chân 10 | VSS — Ground reference |
| Chân 11 | VDD — Positive supply voltage |
| Chân 12 | RB0/INT — Port B bit 0 / external interrupt |
| Chân 13 | RB1 — Port B bit 1 |
| Chân 14 | RB2 — Port B bit 2 |
| Chân 15 | RB3 — Port B bit 3 |
| Chân 16 | RB4 — Port B bit 4 |
| Chân 17 | RB5 — Port B bit 5 |
| Chân 18 | RB6 — Port B bit 6 |
| Chân 19 | RB7 — Port B bit 7 |
| Chân 20 | VSS — Ground reference |
| Chân 21 | VDD — Positive supply voltage |
| Chân 22 | RC0 — Port C bit 0 |
| Chân 23 | RC1 — Port C bit 1 |
| Chân 24 | RC2 — Port C bit 2 |
| Chân 25 | RC3 — Port C bit 3 |
| Chân 26 | RC4 — Port C bit 4 |
| Chân 27 | RC5 — Port C bit 5 |
| Chân 28 | RC6 — Port C bit 6 |
| Chân 29 | RC7 — Port C bit 7 |
| Chân 30 | VSS — Ground reference |
| Chân 31 | VDD — Positive supply voltage |
| Chân 32 | RD0/PSP0 — Port D bit 0 / Parallel Slave Port bit 0 |
| Chân 33 | RD1/PSP1 — Port D bit 1 / Parallel Slave Port bit 1 |
| Chân 34 | RD2/PSP2 — Port D bit 2 / Parallel Slave Port bit 2 |
| Chân 35 | RD3/PSP3 — Port D bit 3 / Parallel Slave Port bit 3 |
| Chân 36 | RD4/PSP4 — Port D bit 4 / Parallel Slave Port bit 4 |
| Chân 37 | RD5/PSP5 — Port D bit 5 / Parallel Slave Port bit 5 |
| Chân 38 | RD6/PSP6 — Port D bit 6 / Parallel Slave Port bit 6 |
| Chân 39 | RD7/PSP7 — Port D bit 7 / Parallel Slave Port bit 7 |
| Chân 40 | VSS — Ground reference |
| Chân 41 | VDD — Positive supply voltage |
| Chân 42 | RE0/RD — Port E bit 0 / Parallel Slave Port read strobe |
| Chân 43 | RE1/WR — Port E bit 1 / Parallel Slave Port write strobe |
| Chân 44 | RE2/CS — Port E bit 2 / Parallel Slave Port chip select |
Ứng dụng tiêu biểu
PIC17C42A-33/PQ phù hợp cho 6 Áp dụngs: Industrial Control Boards, Stepper Motor and PWM Front-End, Instrument Front-Panel Controllers, Legacy Embedded Serial-Control Nodes, PIC16C5X/PIC12CXXX Firmware Upgrades, Security Keypad and Access Modules.
Industrial Control Boards
The PIC17C42A-33/PQ fits industrial control boards because it combines 33 I/O lines with 8.25 MIPS throughput, enough to scan matrix keypads, drive relay arrays, and poll sensors in real time without an external bus expander. At 33 MHz the controller can service a 1 ms control loop with margin to spare for serial diagnostics. Place the MCU near the field connectors to keep digital traces short, and use the USART for a Modbus-style service port. Compared to a modern PIC18F, the OTP memory means firmware must be perfect at production - remote field updates are impossible.
Được đề xuất
Stepper Motor and PWM Front-End
The PIC17C42A-33/PQ's Capture/Compare/PWM peripherals and 33 MHz clock let it generate the multi-phase step/direction signals needed to drive stepper motor drivers or three-phase PWM for small BLDC fans. The 121 ns instruction cycle means PWM update rates can reach tens of kHz with CPU headroom for closed-loop PI control. Use PORTB for pulse outputs and PORTC for direction/enable signals, leaving the USART free for a tuning interface. Designers should decouple VDD close to the IC and use a Schottky on MCLR for clean resets.
Được đề xuất
Instrument Front-Panel Controllers
The PIC17C42A-33/PQ is well-matched to instrument front-panel controllers because 33 I/O pins can directly drive 7-segment displays, rotary encoders, and key matrices without a port expander. The 8-bit parallel slave port allows a host CPU (or DSP) to update display memory quickly, while the MCU handles local scanning and key debounce. At 33 MHz the panel scan rate comfortably exceeds 100 Hz to avoid visible flicker. Choose the MQFP-44 package when the panel is small and SMT assembly is preferred over through-hole.
Được đề xuất
Legacy Embedded Serial-Control Nodes
The PIC17C42A-33/PQ's hardware USART plus 33 MHz throughput make it a capable serial-control node on RS-232/RS-485 buses, handling framed protocols at 115200 baud with CPU cycles to spare for parsing and CRC. The 4 KB OTP holds a slim command interpreter comfortably, and the 232-byte RAM is enough for buffering. Field nodes typically run at 5 V with the MCU between the transceiver and the sensor front-end. For modern designs, prefer a PIC16LF or PIC18F with Flash so firmware bugs can be patched in the field.
Được đề xuất
PIC16C5X/PIC12CXXX Firmware Upgrades
The PIC17C42A-33/PQ is upwards-compatible with the PIC16C5X, PIC12CXXX, and PIC16CXX instruction families, so it is the natural migration target when those parts run out of I/O or code space. The Harvard bus and similar peripheral model mean existing firmware ports with minor header changes. At 33 MHz the new MCU provides 4-8x the throughput of older 4-10 MHz PIC16C5X parts, allowing more complex control loops on the same PCB. Verify interrupt-vector mapping when porting, because PIC17C42A has a multi-vector interrupt controller.
Được đề xuất
Security Keypad and Access Modules
The PIC17C42A-33/PQ supports security keypad and access-control modules because it can scan a 4x4 matrix plus drive a relay, buzzer, and Wiegand output all from its 33 I/O pins - no external mux needed. The 4 KB OTP holds a card-format library, and the 33 MHz clock handles Wiegand timing precisely. The OTP memory prevents firmware tampering by an attacker, a security plus. For new designs prefer a PIC18F Flash MCU with secure firmware-update flow, but the PIC17C42A remains viable for mature products with locked firmware.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho PIC17C42A-33/PQ — 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-25/PQ | PIC17C42A-16/PQ | PIC17C42A-25/PT | PIC17C42A-25E/P |
|---|---|---|---|---|---|
| Package | 44-pin MQFP (PQ) | 44-pin MQFP (PQ) | 44-pin MQFP (PQ) | 44-pin TQFP (PT) | 40-pin PDIP (P) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Max CPU Frequency | 33 MHz | 25 MHz | 16 MHz | 25 MHz | 25 MHz |
| Program Memory | 4 KB OTP (2K x 16) | 4 KB OTP (2K x 16) | 4 KB OTP (2K x 16) | 4 KB OTP (2K x 16) | 4 KB OTP (2K x 16) |
| RAM Size | 232 bytes | 232 bytes | 232 bytes | 232 bytes | 232 bytes |
| I/O Pins | 33 | 33 | 33 | 33 | 33 |
| Throughput (MIPS) | 8.25 MIPS | 6.25 MIPS | 4.0 MIPS | 6.25 MIPS | 6.25 MIPS |
| Oscillator | External | External | External | External | External |
Bảo phân biệt quan trọng
- Highest-speed grade of the PIC17C42A family (vsPIC17C42A-25/PQ)
- Up to 8.25 MIPS - 2x faster than PIC17C42A-16/PQ (vsPIC17C42A-16/PQ)
- 33 I/O pins - the highest in the family (vsPIC17C42A-25E/P)
- 8-bit Parallel Slave Port included (vsPIC16LF877-04/P)
Ghi chú thiết kế
Place a 100 nF decoupling capacitor as close as possible to each VDD pin and a single 10 uF bulk capacitor at the board supply entry. The PIC17C42A-33/PQ has four VDD pins (11, 21, 31, 41) and four VSS pins (10, 20, 30, 40) - every pair must be decoupled. Switching transients on VDD are a common cause of intermittent resets at 33 MHz; a ferrite bead in series with the supply can help in noisy industrial environments.
Do not confuse the PIC17C42A-33/PQ (44-pin MQFP, OTP) with the PIC17C42A-25/PT (44-pin TQFP, OTP) - the packages have the same pin count but different lead pitches and PCB land patterns. Mixing them will cause soldering defects. Also note that PIC17C42A is OTP, not Flash: firmware bugs cannot be patched in-circuit, so verify code with an emulator and windowed parts before committing to production volumes.
Route the external oscillator traces (OSC1, OSCC2) as short, symmetric differential-style traces with a ground guard ring. Keep digital switching signals away from OSC1/OSC2 to minimize clock jitter. Place the 33 MHz crystal as close as possible to the IC and use a pi-network of load capacitors matched to the crystal's load specification; typical values are 15-33 pF. Estimated: for a 33 MHz fundamental crystal with 20 pF load, use two 30 pF capacitors from each leg to ground.
The PIC17C42A-33/PQ's Parallel Slave Port (PSP) lines PSP0-PSP7 can source/sink significant transient current when switching 8 bits simultaneously. If the PSP connects to a fast host bus, add 33 ohm series resistors near the MCU to dampen reflections. PORTE (RE0/RD, RE1/WR, RE2/CS) should be pulled high through 10 kohm resistors to ensure defined logic levels when the PSP is disabled.
Thông tin tuân thủ
RoHS / REACH / lead-free status not confirmed in the verified distributor data; check with Microchip directly. Not AEC-Q100 qualified (consumer/industrial grade, not automotive). Microchip recommends PIC18F4220 for new automotive or industrial designs.
