PIC16CR74-I/P - 8-Bit ROM MCU, 7KB ROM, 20MHz, 40-DIP | Microchip
MPN: PIC16CR74-I/P ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.5 | $8.50 |
| 10 | $7.65 | $76.50 |
| 100 | $6.8 | $680.00 |
| 500 | $6.1 | $3,050.00 |
| 1,000 | $5.45 | $5,450.00 |
PIC16CR74-I/P Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory, working RAM, and peripheral interfaces. The PIC architecture uses a Harvard design with a separate program and data bus, which allows instruction fetch and operand read to occur in the same cycle. Within the broader taxonomy, this part is a ROM-based MCU (mask-ROM programmed at the factory) - the lowest-cost variant of the PIC mid-range line, intended for high-volume production where OTP/Flash reprogrammability is not required.
Key features include a RISC instruction set with only 35 single-word instructions, 14-bit wide instruction word, 8-bit data path, an integrated analog comparator, capture/compare/PWM (CCP) module, synchronous serial port (SSP) supporting SPI and I2C, USART for asynchronous serial communication, and a 10-bit ADC with up to 8 input channels. The industrial temperature grade (-40C to +85C) and 5V operation make it suitable for factory-floor equipment.
Technical depth: the PIC16CR74 uses a 2-stage pipeline with an 8-level deep hardware stack and executes one instruction per instruction cycle (4 clock periods). At 20 MHz this yields 5 MIPS throughput. The ROM variant cannot be reprogrammed - the program is masked into the silicon at wafer fab - making the part low-cost but unsuitable for development or low-volume production, where PIC16F74 (Flash) or PIC16C74 (OTP/EPROM) siblings are preferred.
Typical applications include industrial control logic boards, appliance controllers, automotive body electronics (pre-CAN era), HVAC control panels, instrumentation front-ends, and educational microcontroller labs. The wide I/O count (33 pins) supports direct connection to keypads, LED displays, and relay drivers.
Design consideration: when migrating a design from PIC16CR74 to Flash-based siblings, verify that the ROM-stored calibration constants (if any) and interrupt vector behavior match. The PIC16CR74 lacks the in-circuit debugger (ICD) interface of later PIC16F parts, so emulator or ICE tools are required for firmware bring-up.
This page synthesizes distributor pricing snapshots, a curated drop-in alternative list drawn from the same PIC16C7X family, and practical design notes that complement the official Microchip datasheet - a working reference for engineers maintaining legacy PIC mid-range designs.
Drop-in alternatives for PIC16CR74-I/P — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F74-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C74B-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C74A-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C74-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F77-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C77-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16CR74-I/P Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC |
| Program Memory Type | ROM (mask-programmed) |
| Program Memory Size | 7 KB (4K x 14) |
| RAM | 192 bytes |
| EEPROM Data Memory | None (ROM part) |
| Maximum Clock Frequency | 20 MHz |
| Instruction Cycle Throughput | 5 MIPS (1 instruction per 4 clocks) |
| Number of I/O Pins | 33 |
| Supply Voltage | 5 V nominal (typical PIC16C range) |
| Operating Temperature Range | -40C to +85C (Industrial) |
| Package | 40-pin PDIP (DIP-40, 0.600 inch / 15.24 mm) |
| Mounting Type | Through-Hole |
| ADC | 10-bit, up to 8 channels |
| Serial Interfaces | USART (SCI), SSP (SPI/I2C) |
| Peripherals | CCP, Analog Comparator, WDT, POR, BOR |
| Number of Instructions | 35 single-word instructions |
| Instruction Width | 14 bits |
| Stack Depth | 8-level hardware stack |
| Temperature Grade | Industrial (I) |
| RoHS Status | Compliant (verify per lot) |
PIC16CR74-I/P Pin Configuration
| Pin 1 | MCLR/VPP — Master Clear (reset) input / programming voltage |
| Pin 2 | RA0/AN0 — PORTA bit 0 / analog input 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / analog input 1 |
| Pin 4 | RA2/AN2 — PORTA bit 2 / analog input 2 |
| Pin 5 | RA3/AN3/VREF+ — PORTA bit 3 / analog input 3 / ADC voltage reference + |
| Pin 6 | RA4/T0CKI — PORTA bit 4 / Timer 0 clock input |
| Pin 7 | RA5/AN4/SS — PORTA bit 5 / analog input 4 / SPI slave select |
| Pin 8 | RE0/RD/AN5 — PORTE bit 0 / read control for PSP / analog input 5 |
| Pin 9 | RE1/WR/AN6 — PORTE bit 1 / write control for PSP / analog input 6 |
| Pin 10 | RE2/CS/AN7 — PORTE bit 2 / chip select for PSP / analog input 7 |
| Pin 11 | VDD — Positive supply voltage (+5V) |
| Pin 12 | VSS — Ground reference |
| Pin 13 | OSC1/CLKIN — Oscillator crystal input / external clock input |
| Pin 14 | OSC2/CLKOUT — Oscillator crystal output / clock output (Fosc/4) |
| Pin 15 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer 1 oscillator output / Timer 1 clock input |
| Pin 16 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer 1 oscillator input / CCP2 module |
| Pin 17 | RC2/CCP1 — PORTC bit 2 / Capture Compare PWM 1 |
| Pin 18 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 19 | RD0/PSP0 — PORTD bit 0 / Parallel Slave Port bit 0 |
| Pin 20 | RD1/PSP1 — PORTD bit 1 / Parallel Slave Port bit 1 |
| Pin 21 | RD2/PSP2 — PORTD bit 2 / Parallel Slave Port bit 2 |
| Pin 22 | RD3/PSP3 — PORTD bit 3 / Parallel Slave Port bit 3 |
| Pin 23 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 24 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 25 | RC6/TX/CK — PORTC bit 6 / USART transmit / USART clock |
| Pin 26 | RC7/RX/DT — PORTC bit 7 / USART receive / USART data |
| Pin 27 | RD4/PSP4 — PORTD bit 4 / Parallel Slave Port bit 4 |
| Pin 28 | RD5/PSP5 — PORTD bit 5 / Parallel Slave Port bit 5 |
| Pin 29 | RD6/PSP6 — PORTD bit 6 / Parallel Slave Port bit 6 |
| Pin 30 | RD7/PSP7 — PORTD bit 7 / Parallel Slave Port bit 7 |
| Pin 31 | VSS — Ground reference |
| Pin 32 | VDD — Positive supply voltage (+5V) |
| Pin 33 | RB0/INT — PORTB bit 0 / external interrupt input |
| Pin 34 | RB1 — PORTB bit 1 |
| Pin 35 | RB2 — PORTB bit 2 |
| Pin 36 | RB3 — PORTB bit 3 |
| Pin 37 | RB4 — PORTB bit 4 |
| Pin 38 | RB5 — PORTB bit 5 |
| Pin 39 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 40 | RB7/PGD — PORTB bit 7 / ICSP data |
Typical Applications
PIC16CR74-I/P is suitable for 7 applications: Industrial Control Logic Boards, Appliance Control Panels, Automotive Body Electronics (Pre-CAN), HVAC Control Panels and Thermostats, Instrumentation Front-Ends, Educational Microcontroller Labs, Security and Access Control Panels.
Industrial Control Logic Boards
The PIC16CR74-I/P's 33 digital I/O pins, 5V operation, and industrial -40C to +85C temperature grade make it a long-standing workhorse for factory-floor control boards that drive relays, read limit switches, and sequence motors. The integrated 10-bit ADC samples analog sensor inputs (pressure, temperature, position) directly, while the CCP module generates PWM outputs for proportional valve control and the USART links the board to a PLC or HMI panel. At 5 MIPS throughput, the core handles 8-10 kHz PID loops with software-implemented control law. Because mask ROM locks the firmware into silicon, the part resists field tampering - a useful property for production equipment sold into regulated industries.
Recommended
Appliance Control Panels
The PIC16CR74-I/P was widely deployed in washing machines, dishwashers, ovens, and HVAC thermostats where its 33 I/O pins scan keypads, drive seven-segment LED displays, switch triac-driven AC loads, and read NTC temperature sensors through the on-chip ADC. The 5V operation and CMOS low-power design fit battery-backed appliance clocks, and the 20 MHz clock supports multiplexed LED refresh rates above 100 Hz to avoid flicker. Legacy appliance control boards with PIC16CR74 firmware in production typically migrate to PIC16F74-I/P for new tooling while keeping the firmware source compatible, since the instruction set and SFR map are identical.
Recommended
Automotive Body Electronics (Pre-CAN)
Before CAN bus became universal, the PIC16CR74-I/P was used in body control modules for window regulators, mirror actuators, seat controllers, and interior lighting sequencers. Its 33 I/O pins drive multiple MOSFET bridges, the USART talks to other microcontrollers via LIN-like single-wire protocols, and the 10-bit ADC reads battery voltage and current-sense amplifiers. The industrial temperature grade (-40C to +85C) handles cabin environments, though under-hood applications required the extended 'E' grade. New automotive designs migrate to PIC18 or dsPIC parts with CAN, but legacy service stock relies on PIC16CR74 supply.
Recommended
HVAC Control Panels and Thermostats
The PIC16CR74-I/P's 10-bit ADC with 8 input channels reads multiple NTC thermistors (return air, supply air, outdoor, coil, freeze protection), while the CCP module drives PWM outputs to modulate furnace gas valves, blower fan speeds, and damper servos. The USART links the thermostat to a network of indoor unit controllers, and the on-chip analog comparator implements safety cutoffs on temperature extremes. With 7KB of ROM, the firmware supports full PID control loops, weekly scheduling, and LCD menu handling - sufficient for residential and light-commercial HVAC controllers throughout the late 1990s and 2000s.
Recommended
Instrumentation Front-Ends
Bench-top multimeters, laboratory data loggers, and process calibrators used the PIC16CR74-I/P as a measurement front-end: the 10-bit ADC digitizes thermocouple and 4-20 mA loop inputs, the USART outputs RS-232 to a PC or terminal, and the 33 I/O pins drive the keypad matrix, LCD interface, and range-relay switching. The industrial temperature range and CMOS noise immunity suit shielded instrument enclosures. For higher-precision (16-bit or 24-bit) ADC requirements, designers paired the PIC16CR74 with external sigma-delta converters over SPI; this pattern remains valid when migrating to PIC16F74-I/P.
Recommended
Educational Microcontroller Labs
Universities and technical colleges adopted the PIC16CR74-I/P in the late 1990s as a teaching platform for assembly-language programming, interrupt handling, and peripheral interfacing. The 40-pin PDIP package is breadboard-friendly, the 33 I/O pins are easy to probe with oscilloscopes, and the simple 35-instruction RISC set lets students learn instruction pipelining without overwhelming complexity. While new courses now use PIC16F1X or PIC18 parts for Flash convenience, existing PIC16CR74 lab kits remain in use; the PIC16F74-I/P is the recommended substitute since it shares the same pinout, instruction set, and assembly language toolchain (MPASM / MPLAB).
Recommended
Security and Access Control Panels
Burglar alarm control panels, access controllers, and keypad-entry systems used the PIC16CR74-I/P because its 33 I/O pins scan 4x4 or 8x8 keypad matrices, drive piezo buzzers and relay outputs, read reed switches and PIR sensors through the ADC, and supervise battery-backed operation. The on-chip analog comparator implements tamper detection on sensor loops. Mask ROM prevents firmware reverse-engineering by competitors in the security market, a feature valued in commercial alarm panels. Service replacements typically use PIC16F74-I/P because authorized installers can reflash firmware in the field without replacing the silicon.
Recommended
Recommended Products Summary
Engineering reference data for PIC16CR74-I/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F74-I/P | PIC16C74B-I/P | PIC16C74A-I/P | PIC16C74-I/P | PIC16F77-I/P | PIC16C77-I/P |
|---|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | DIP-40 (PDIP, 0.600") | DIP-40 (PDIP, 0.600") - same | DIP-40 (PDIP, 0.600") - same | DIP-40 (PDIP, 0.600") - same | DIP-40 (PDIP, 0.600") - same | DIP-40 (PDIP, 0.600") - same | DIP-40 (PDIP, 0.600") - same |
| Program Memory Type | Mask ROM (7 KB) | Flash (7 KB) | EPROM OTP (7 KB) | EPROM OTP (7 KB) | EPROM OTP (7 KB) | Flash (14 KB) | EPROM OTP (14 KB) |
| Maximum Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| RAM | 192 bytes | 192 bytes | 192 bytes | 192 bytes | 192 bytes | 368 bytes | 368 bytes |
| I/O Pins | 33 | 33 | 33 | 33 | 33 | 33 | 33 |
| ADC Channels | 8 x 10-bit | 8 x 10-bit | 8 x 10-bit | 8 x 10-bit | 8 x 10-bit | 8 x 10-bit | 8 x 10-bit |
| In-Circuit Programming / Debug | No (ROM part, no ICD) | Yes (Flash + ICD) | No (EPROM OTP) | No (EPROM OTP) | No (EPROM OTP) | Yes (Flash + ICD) | No (EPROM OTP) |
| Lifecycle Status | Obsolete | Active (recommended replacement) | Obsolete (limited stock) | Obsolete (limited stock) | Obsolete (limited stock) | Active | Obsolete (limited stock) |
Key Differentiators
- Mask ROM firmware protection (vs PIC16F74-I/P (Flash))
- Larger program memory in same pinout (vs PIC16F74-I/P (7KB Flash))
- EP-based reprogrammability vs mask ROM (vs PIC16C74-I/P (OTP EPROM))
Design Notes
The PIC16CR74-I/P is a mask-ROM part and cannot be re-programmed in-circuit. Before committing to a PCB layout, verify that the masked firmware image is fully validated and locked - any firmware bug requires a new silicon run (NRE charge and minimum order quantity in the thousands). For prototypes and low-volume production, choose PIC16F74-I/P instead. Engineers migrating legacy CR74 firmware to F74 should verify that the CONFIG word bits and oscillator configuration match, since the F74 default differs slightly.
Place a 100 nF decoupling capacitor as close as possible to each pair of VDD/VSS pins (pins 11/12 and pins 31/32). Add a 10 uF bulk tantalum or aluminum capacitor at the board power entry. The MCLR/VPP pin (pin 1) should be pulled up to VDD through a 10 kohm resistor and decoupled with a 100 pF capacitor to prevent spurious resets from noise. For ICSP on Flash-based siblings, ensure the PGC (RB6) and PGD (RB7) lines have no strong pull-ups that would interfere with programming.
The PIC16CR74-I/P operates from 4.0V to 6.0V on VDD (typical 5V PIC16C range). The brown-out reset (BOR) circuit and power-on reset (POR) ensure clean startup, but verify the VDD rise time is at least 0.05 V/ms for proper POR sequencing. At 20 MHz clock and full I/O switching, the supply current can reach 20-30 mA; design the 5V regulator for at least 50 mA headroom. Sleep mode reduces current to under 5 uA, suitable for battery-backed applications.
Keep the OSC1/OSC2 crystal traces short and symmetric, with the crystal load capacitors placed directly at the oscillator pins. Use a ground guard ring around the crystal to reduce EMI coupling into the clock. For analog inputs (RA0-RA5 and RE0-RE2), route analog traces away from digital switching lines; the 10-bit ADC is sensitive to digital switching noise on adjacent pins. If high ADC accuracy is required, add a small RC low-pass filter (100 ohm + 100 nF) on each analog input.
Compliance Information
RoHS and lead-free status depend on manufacturing date-code; pre-2006 lots typically use SnPb finish (non-RoHS), post-2010 franchised-distributor stock is generally RoHS-compliant. AEC-Q100 not applicable for industrial-grade MCU. Conflict-minerals compliance declared per Microchip policy.
