PIC16F874-20/P - 8-Bit 20MHz 7KB Flash MCU | Microchip
MPN： PIC16F874-20/P ✓ 啟用中PIC16F874-20/P 概覽
What is an 8-bit Flash microcontroller? An 8-bit Flash microcontroller is a single-chip computer built around an 8-bit data path, integrating CPU, non-volatile Flash program memory, RAM, EEPROM, and peripherals onto one die. Within the broader taxonomy it sits as: 8-bit MCU -> microcontroller -> embedded controller -> semiconductor IC. The PIC16F family specifically uses a RISC-style Harvard architecture with only 35 single-word instructions, making it friendly for assembly and C development in embedded systems.
Key features include 5 channels of 10-bit Analog-to-Digital conversion, USART, MSSP (SPI/I2C) interface, two 8-bit timers plus one 16-bit timer, a 10-bit PWM module with Capture/Compare/PWM (CCP), and NanoWatt power management for low-current sleep modes. Watchdog timer, in-circuit serial programming (ICSP), and brown-out reset (BOR) round out the standard embedded feature set.
The PIC16F874 uses a 14-bit instruction word with 200ns instruction execution at 20MHz, plus separate instruction and data buses (Harvard). The CMOS Flash cell supports >100k erase/write cycles and 40-year retention, qualifying it for industrial embedded products requiring long field life.
Typical applications include industrial control panels, HVAC thermostats, sensor signal conditioning, motor control boards, and small appliances. The 40-pin DIP package suits through-hole prototyping and legacy board retrofits where socket replacement is desirable.
When designing with the PIC16F874-20/P, observe the 4.0V to 5.5V supply range. For new designs, Microchip recommends the PIC16F884 (NanoWatt enhanced, more memory). For this page we synthesized distributor pricing, drop-in alternatives sharing the 40-pin DIP footprint, and design notes not present in the manufacturer datasheet alone.
直接替換替代品，適用於 PIC16F874-20/P — 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： PIC16F874-20/P （相同外形與佔位） — 差異在於 ADC, Operating Temperature, Package, Timers, Core Architecture.
PIC16F877-20/P
✅ 直接替換聯絡詢價
查看資料表 →PIC16F874-04/PQ
✅ 直接替換聯絡詢價
查看資料表 →PIC16F874-10/P
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
PIC16F874-20I/P
✅ 直接替換📋 參考替代品（不在目錄中）
PIC16F884-I/P
✅ 直接替換 ⚠️ 規格未經驗證聯絡詢價
查看資料表 →PIC16F877A-20/P
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
PIC16F874-20/P 最大額定值與電氣特性
| Core | PIC 8-bit RISC (Harvard) |
| Instruction Set | 35 single-word instructions, 14-bit wide |
| Program Memory | 7 KB Flash (4K x 14) |
| RAM | 192 bytes |
| EEPROM | 128 bytes |
| Max CPU Speed | 20 MHz (200 ns instruction cycle) |
| 供應電壓 | 4.0 V to 5.5 V |
| I/O Pins | 33 |
| ADC | 10-bit, up to 8 channels |
| Timers | Timer0 (8-bit), Timer1 (16-bit), Timer2 (8-bit with PWM) |
| PWM / CCP | 1 CCP module, 10-bit PWM |
| Serial Interfaces | USART (RS-232/RS-485) + MSSP (SPI / I2C) |
| 封裝 | 40-pin PDIP (DIP-40), through-hole |
| 工作溫度 | -40 C to +85 C (industrial) |
| Programming | In-Circuit Serial Programming (ICSP) |
| RoHS 狀態 | Compliant |
PIC16F874-20/P 腳位配置
| 腳位 1 | MCLR/VPP — Master clear reset input / programming voltage |
| 腳位 2 | RA0/AN0 — PORTA bit 0 / analog input channel 0 |
| 腳位 3 | RA1/AN1 — PORTA bit 1 / analog input channel 1 |
| 腳位 4 | RA2/AN2 — PORTA bit 2 / analog input channel 2 |
| 腳位 5 | RA3/AN3/VREF- — PORTA bit 3 / analog input channel 3 / negative VREF |
| 腳位 6 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input (open-drain) |
| 腳位 7 | RA5/AN4/SS — PORTA bit 5 / analog input channel 4 / SPI slave select |
| 腳位 8 | RE0/RD/AN5 — PORTE bit 0 / read control / analog input channel 5 |
| 腳位 9 | RE1/WR/AN6 — PORTE bit 1 / write control / analog input channel 6 |
| 腳位 10 | RE2/CS/AN7 — PORTE bit 2 / chip select / analog input channel 7 |
| 腳位 11 | VDD — Positive supply (4.0 V to 5.5 V) |
| 腳位 12 | VSS — Ground |
| 腳位 13 | OSC1/CLKIN — Oscillator crystal input / external clock input |
| 腳位 14 | OSC2/CLKOUT — Oscillator crystal output / clock output |
| 腳位 15 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / clock input |
| 腳位 16 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / CCP2 |
| 腳位 17 | RC2/CCP1 — PORTC bit 2 / Capture Compare PWM 1 output |
| 腳位 18 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| 腳位 19 | RD0/PSP0 — PORTD bit 0 / parallel slave port bit 0 |
| 腳位 20 | RD1/PSP1 — PORTD bit 1 / parallel slave port bit 1 |
| 腳位 21 | RD2/PSP2 — PORTD bit 2 / parallel slave port bit 2 |
| 腳位 22 | RD3/PSP3 — PORTD bit 3 / parallel slave port bit 3 |
| 腳位 23 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| 腳位 24 | RC5/SDO — PORTC bit 5 / SPI data out |
| 腳位 25 | RC6/TX/CK — PORTC bit 6 / USART TX / synchronous clock |
| 腳位 26 | RC7/RX/DT — PORTC bit 7 / USART RX / synchronous data |
| 腳位 27 | RD4/PSP4 — PORTD bit 4 / parallel slave port bit 4 |
| 腳位 28 | RD5/PSP5 — PORTD bit 5 / parallel slave port bit 5 |
| 腳位 29 | RD6/PSP6 — PORTD bit 6 / parallel slave port bit 6 |
| 腳位 30 | RD7/PSP7 — PORTD bit 7 / parallel slave port bit 7 |
| 腳位 31 | VSS — Ground (second VSS pin) |
| 腳位 32 | VDD — Positive supply (second VDD pin) |
| 腳位 33 | RB0/INT — PORTB bit 0 / external interrupt input |
| 腳位 34 | RB1 — PORTB bit 1 |
| 腳位 35 | RB2 — PORTB bit 2 |
| 腳位 36 | RB3/PGM — PORTB bit 3 / low-voltage programming enable |
| 腳位 37 | RB4 — PORTB bit 4 |
| 腳位 38 | RB5 — PORTB bit 5 |
| 腳位 39 | RB6/PGC — PORTB bit 6 / in-circuit serial programming clock |
| 腳位 40 | RB7/PGD — PORTB bit 7 / in-circuit serial programming data |
典型應用
PIC16F874-20/P 適用於 6 應用s: Industrial Control Panels, HVAC Thermostats, Sensor Signal Conditioning Boards, Motor Control Boards (DC / Stepper), Small Appliance Controllers, Educational / Hobbyist Embedded Projects.
Industrial Control Panels
The PIC16F874-20/P fits industrial control panels because its 4.0-5.5V supply range matches legacy 5V PLC backplanes, the 33 I/O pins drive relay arrays or opto-isolators directly, and the USART interfaces with RS-485 Modbus networks. The 7 KB Flash fits typical ladder-style state machines, and the -40 to +85 C industrial grade tolerates cabinet environments. Compared with the newer PIC16F884, this part still has plenty of headroom for relay logic, button debouncing, and LED drivers in non-safety-critical HMIs and SCADA terminals.
推薦
HVAC Thermostats
The PIC16F874-20/P suits HVAC thermostat designs with its 10-bit ADC reading thermistor or RTD sensors, PWM module driving TRIAC angle-control for heating stages, and 192 B RAM handling schedule lookups. The 128 B EEPROM retains user setpoints across power cycles. Brown-out reset avoids false triggering on brownouts in older building wiring. Its 40-pin PDIP footprint is friendly to through-hole boards typical in white-goods manufacturing, and ICSP programming allows the same firmware to be patched in production.
推薦
Sensor Signal Conditioning Boards
Using the PIC16F874-20/P for sensor signal conditioning gives designers an 8-channel 10-bit ADC for bridge sensors or thermopiles, MSSP running I2C to digital sensor companions, and USART for RS-232 diagnostics on calibration. The 35-instruction RISC core easily keeps up with 1 kHz loop rates typical of process-control loops. EEPROM stores calibration coefficients that the host reads at startup, and the 20MHz CPU executes linearization math in microseconds. The DIP package supports hand-soldered prototype calibration boards.
推薦
Motor Control Boards (DC / Stepper)
In small DC and stepper motor control boards, the PIC16F874-20/P provides a 16-bit Timer1 for quadrature decode of an encoder and a 10-bit PWM module for current-mode drive. The 33 I/O lines talk to logic-level MOSFET gate drivers and endstop sensors, and 192 B RAM is enough for a 50-state microstep sequencer. Brown-out reset and watchdog timer protect pumps and actuators in unattended installations. Designers should size the PCB copper pour for return paths on the 4-quadrant H-bridge; this part handles the logic while a gate driver handles the power stage.
推薦
Small Appliance Controllers
Small home appliances like coffee makers, vacuum robots, and countertop ovens run well on the PIC16F874-20/P, where the USART links to a Wi-Fi/BT companion, the ADC reads temperature and water-level sensors, and PWM drives a triac or DC motor. The 7 KB Flash fits typical appliance software with menu logic and safety interlocks. Through-hole DIP eases automated hand-repair lines, and ICSP allows last-minute firmware tweaks on the production floor. Watchdog timer is essential for kitchen safety interlocks.
推薦
Educational / Hobbyist Embedded Projects
The PIC16F874-20/P is widely used in university and hobbyist courses that teach assembly and embedded C, thanks to its 35-instruction RISC architecture, generous Flash (7 KB), and easy-to-socket 40-pin DIP footprint. Students program it with PICkit 2/3 and the MPLAB X IDE without needing surface-mount skills. Its peripherals expose learners to timers, ADC, PWM, USART, and I2C/SPI, covering most embedded-system fundamentals. Compared to a Raspberry Pi, this part teaches low-level register I/O and resource-constrained design.
推薦
推薦產品摘要
工程參考資料，適用於 PIC16F874-20/P — 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 | PIC16F877-20/P | PIC16F874-04/P | PIC16F884-I/P | PIC16F877A-20/P |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 40-pin PDIP | 40-pin PDIP - same | 40-pin PDIP - same | 40-pin PDIP - same | 40-pin PDIP - same |
| Max CPU Speed | 20 MHz | 20 MHz | 4 MHz (-80%) | 20 MHz | 20 MHz |
| Program Memory | 7 KB Flash | 14 KB Flash (+100%) | 7 KB Flash (same) | 14 KB Flash (+100%) | 14 KB Flash (+100%) |
| RAM | 192 B | 368 B (+92%) | 192 B (same) | 368 B (+92%) | 368 B (+92%) |
| EEPROM | 128 B | 256 B (+100%) | 128 B (same) | 256 B (+100%) | 256 B (+100%) |
| ADC | 10-bit, 8 ch | 10-bit, 8 ch | 10-bit, 8 ch | 10-bit, 11 ch (NanoWatt) | 10-bit, 14 ch (enhanced) |
| NanoWatt Technology | No | No | No | Yes (lower sleep current) | No |
| Operating Voltage | 4.0 V to 5.5 V | 4.0 V to 5.5 V | 4.0 V to 5.5 V | 2.0 V to 5.5 V (wider) | 4.0 V to 5.5 V |
主要差異化特點
- Larger Flash and RAM for the same footprint (對比PIC16F877-20/P)
- Microchip modern replacement with NanoWatt (對比PIC16F884-I/P)
- Higher reliability at half the clock (對比PIC16F874-04/P)
設計說明
Place a 0.1 uF decoupling capacitor on each VDD pin (pins 11 and 32) within 5 mm of the package. Add a 10 uF bulk capacitor at the supply rail. The PIC16F874-20/P is rated 4.0 V to 5.5 V; below 4 V the brown-out reset may assert and halt execution. Estimated: total supply current is approximately 16 mA at 20 MHz / 5 V minus I/O sink currents; design the regulator with at least 50 mA headroom.
Do not leave MCLR floating: tie it to VDD through a 10 kohm resistor and a decoupling capacitor, or to the reset circuit. Floating MCLR triggers random resets and erratic program flow. Note that pin 39 (RB6) and pin 40 (RB7) are dual-purpose ICSP clock/data when MCLR is held high during programming; ensure your PCB does not load these pins with >5 pF or programming will fail.
Keep traces from OSC1/OSC2 (pins 13/14) short and symmetric to ground. Use a watch crystal with 22 pF load capacitors close to the pins, not at the source. Route RC6/TX (pin 25) and RC7/RX (pin 26) traces away from the crystal area to avoid EMI pickup. For an external clock, drive OSC1 only and leave OSC2 floating if CLKOUT is unused.
合規資訊
RoHS/REACH compliant per Microchip product page as of 2026-09-21. Not AEC-Q100 qualified for automotive (use PIC16F874A-20I/PQ for automotive-grade projects).
