PIC17C766/CL - 8-Bit 33MHz 32KB EPROM MCU | Microchip | 84-CERQUAD
MPN: PIC17C766/CL ⚠ Last Time Buy| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $32.5 | $32.50 |
| 10 | $29.2 | $292.00 |
| 100 | $25.8 | $2,580.00 |
| 500 | $22.4 | $11,200.00 |
| 1,000 | $19.95 | $19,950.00 |
PIC17C766/CL Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, non-volatile program memory, working RAM, and configurable peripheral interfaces into one package. PIC microcontrollers follow a Harvard RISC architecture with separate program and data buses, and the PIC17C family sits at the high end of the original PIC16C5X/PIC16CXX lineage, expanding register width to 16 bits while preserving the 58-instruction opcode set that enables fast context switching. The PIC17C766 was targeted at complex embedded control tasks requiring simultaneous parallel I/O expansion and multiple serial communication channels (I2C, SPI, UART/USART).
Key features include 33MHz maximum operating speed, 8.25 MIPS throughput, 32KB (16Kx16) EPROM program memory, 902 bytes of RAM, 66 I/O pins, an external oscillator interface, and a windowed CERQUAD package that allows UV erasure of EPROM for code development and prototyping. The device operates from 5V and is pin-compatible with the lower-memory PIC17C762 and PIC17C756A variants in the same package.
Architecturally, the PIC17C766 uses a 16-bit wide instruction word and a 16-level hardware stack, supporting 58 single-word instructions with single-cycle execution (121 ns @ 33MHz), except for program branches and table reads/writes which are two cycles. The MCU includes three 8-bit I/O ports (PORTA, PORTB, PORTC) plus additional port pins enabled by the 84-pin package, with built-in peripherals for serial communication.
Typical applications include industrial automation controllers, HVAC system controllers, automotive body electronics, security and access control systems, point-of-sale terminals, and any legacy design requiring a high-I/O-count OTP/EPROM microcontroller in a windowed ceramic package for in-circuit emulation or field re-programmability. The /CL suffix denotes the CERQUAD J-lead windowed package for prototype development; production builds use the plastic /L or /PT variants.
When designing with this part, note that the EPROM window is required for UV erasure, so the CERQUAD package is not suitable for high-vibration or cost-sensitive production. Microchip recommends migrating to the PIC18F8520, a flash-based successor with code compatibility, modern peripherals, and a smaller footprint. Ensure your programmer supports the PIC17C family and the 84-CERQUAD package; older EPROM programmers with UV erasers are required for development cycles.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for PIC17C766/CL — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with PIC17C766/CL (same form factor and footprint) — differing in Package, Core Architecture, ADC, Mounting Type, Program Memory Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC17C762-33I/PT
✅ Drop-In✓ In Stock
$4.85 / Unit
View Datasheet →PIC17C762-16I/PT
✅ Drop-In✓ In Stock
$10.05 / Unit
View Datasheet →PIC17C756A-33E/PT
✅ Drop-In✓ In Stock
$7.55 / Unit
View Datasheet →PIC17C756A-16I/PT
✅ Drop-In✓ In Stock
$11.2 / Unit
View Datasheet →PIC17C752-33/PT
✅ Drop-In✓ In Stock
$10.1 / Unit
View Datasheet →PIC17C766/CL Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC (Harvard) |
| Program Memory Type | EPROM (UV-erasable, windowed) |
| Program Memory Size | 32 KB (16K x 16) |
| RAM Size | 902 bytes |
| Maximum CPU Frequency | 33 MHz |
| Instruction Throughput | 8.25 MIPS (121 ns/instruction) |
| Number of I/O Pins | 66 |
| Number of Instructions | 58 single-word |
| Instruction Cycle | 121 ns (single-cycle, 2-cycle for branches) |
| Oscillator Type | External |
| Package Type | 84-CERQUAD windowed (J-Lead), 29.21 x 29.21 mm |
| Mounting Type | Through-Hole (CERQUAD windowed) |
| Operating Supply Voltage | 5 V |
| Communication Interfaces | I2C, SPI, UART/USART |
PIC17C766/CL Pin Configuration
| Pin 1 | RA0/AN0 — PORTA bit 0 / analog input 0 |
| Pin 2 | RA1/AN1 — PORTA bit 1 / analog input 1 |
| Pin 3 | RA2/AN2 — PORTA bit 2 / analog input 2 |
| Pin 4 | RA3/AN3 — PORTA bit 3 / analog input 3 |
| Pin 5 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 6 | RA5/SS — PORTA bit 5 / SPI slave select |
| Pin 7 | VSS — Ground reference |
| Pin 8 | OSC1/CLKI — External oscillator input |
| Pin 9 | OSC2/CLKO — External oscillator output |
| Pin 10 | RB0/INT — PORTB bit 0 / external interrupt |
| Pin 11 | RB1 — PORTB bit 1 |
| Pin 12 | RB2 — PORTB bit 2 |
| Pin 13 | RB3 — PORTB bit 3 |
| Pin 14 | RB4 — PORTB bit 4 |
| Pin 15 | RB5 — PORTB bit 5 |
| Pin 16 | RB6 — PORTB bit 6 |
| Pin 17 | RB7 — PORTB bit 7 |
| Pin 18 | RC0 — PORTC bit 0 |
| Pin 19 | RC1 — PORTC bit 1 |
| Pin 20 | RC2 — PORTC bit 2 |
| Pin 21 | RC3 — PORTC bit 3 |
| Pin 22 | RC4 — PORTC bit 4 |
| Pin 23 | RC5 — PORTC bit 5 |
| Pin 24 | RC6 — PORTC bit 6 |
| Pin 25 | RC7 — PORTC bit 7 |
| Pin 26 | RD0 — PORTD bit 0 |
| Pin 27 | RD1 — PORTD bit 1 |
| Pin 28 | RD2 — PORTD bit 2 |
| Pin 29 | RD3 — PORTD bit 3 |
| Pin 30 | RD4 — PORTD bit 4 |
| Pin 31 | RD5 — PORTD bit 5 |
| Pin 32 | RD6 — PORTD bit 6 |
| Pin 33 | RD7 — PORTD bit 7 |
| Pin 34 | RE0 — PORTE bit 0 |
| Pin 35 | RE1 — PORTE bit 1 |
| Pin 36 | RE2 — PORTE bit 2 |
| Pin 37 | RE3 — PORTE bit 3 |
| Pin 38 | RE4 — PORTE bit 4 |
| Pin 39 | RE5 — PORTE bit 5 |
| Pin 40 | RE6 — PORTE bit 6 |
| Pin 41 | RE7 — PORTE bit 7 |
| Pin 42 | VSS — Ground reference |
| Pin 43 | VDD — Positive supply (5V nominal) |
| Pin 44 | NC — Not connected (per datasheet) |
| Pin 45 | RF0 — PORTF bit 0 |
| Pin 46 | RF1 — PORTF bit 1 |
| Pin 47 | RF2 — PORTF bit 2 |
| Pin 48 | RF3 — PORTF bit 3 |
| Pin 49 | RF4 — PORTF bit 4 |
| Pin 50 | RF5 — PORTF bit 5 |
| Pin 51 | RF6 — PORTF bit 6 |
| Pin 52 | RF7 — PORTF bit 7 |
| Pin 53 | RG0 — PORTG bit 0 |
| Pin 54 | RG1 — PORTG bit 1 |
| Pin 55 | RG2 — PORTG bit 2 |
| Pin 56 | RG3 — PORTG bit 3 |
| Pin 57 | RG4 — PORTG bit 4 |
| Pin 58 | VSS — Ground reference |
| Pin 59 | VDD — Positive supply (5V nominal) |
| Pin 60 | SCL — I2C clock (open-drain) |
| Pin 61 | SDA — I2C data (open-drain) |
| Pin 62 | SCK — SPI clock |
| Pin 63 | SDI — SPI data in |
| Pin 64 | SDO — SPI data out |
| Pin 65 | TX/CK — UART transmit / clock |
| Pin 66 | RX/DT — UART receive / data |
| Pin 67 | RH0 — PORTH bit 0 |
| Pin 68 | RH1 — PORTH bit 1 |
| Pin 69 | RH2 — PORTH bit 2 |
| Pin 70 | RH3 — PORTH bit 3 |
| Pin 71 | RH4 — PORTH bit 4 |
| Pin 72 | RH5 — PORTH bit 5 |
| Pin 73 | RH6 — PORTH bit 6 |
| Pin 74 | RH7 — PORTH bit 7 |
| Pin 75 | RI0 — PORTI bit 0 |
| Pin 76 | RI1 — PORTI bit 1 |
| Pin 77 | RI2 — PORTI bit 2 |
| Pin 78 | RI3 — PORTI bit 3 |
| Pin 79 | MCLR/VPP — Master clear reset / EPROM programming voltage |
| Pin 80 | VDD — Positive supply (5V nominal) |
| Pin 81 | VSS — Ground reference |
| Pin 82 | NC — Not connected (per datasheet) |
| Pin 83 | NC — Not connected (per datasheet) |
| Pin 84 | NC — Not connected (per datasheet) |
Typical Applications
PIC17C766/CL is suitable for 6 applications: Industrial Automation Controller, HVAC System Controller, Point-of-Sale Terminal, Security Access Control System, Automotive Body Electronics, Legacy Industrial Embedded Board.
Industrial Automation Controller
The PIC17C766/CL fits industrial automation controllers because its 66 I/O pins directly drive multi-axis stepper drivers, opto-isolated inputs, and relay outputs without external I/O expanders. The 32KB EPROM stores ladder-logic-equivalent state machines for PLC-style sequencing, while the 902-byte RAM buffers sensor telemetry between UART and SPI peripherals. At 33MHz the 8.25 MIPS throughput sustains deterministic scan loops below 1 ms, meeting IEC 61131-3 timing for small-scale control cabinets. The I2C and SPI masters interface with digital temperature sensors, EEPROM parameter stores, and HMI displays simultaneously. Designers building conveyor, packaging, or pump controllers benefit from the proven PIC17C core, though new builds should evaluate PIC18F8520 for flash-based field firmware updates and CAN bus integration required by modern factory networks.
Recommended
HVAC System Controller
The PIC17C766/CL fits HVAC system controllers because its 66 I/O pins interface with multi-zone temperature sensors, damper actuators, and three-speed fan relays without external logic. The 32KB EPROM accommodates multi-stage control algorithms including PID loops, defrost cycles, and error recovery state machines. The UART/USART peripheral streams telemetry to a building management system over RS-485, while SPI drives a graphic LCD showing zone status. At 33MHz the core executes 8.25 MIPS, ensuring closed-loop temperature regulation stays under 100 ms even with 16 active zones. The EPROM memory is ideal for long-life HVAC deployments where firmware rarely changes, and the 84-CERQUAD package supports field serviceability through UV erasure during commissioning.
Recommended
Point-of-Sale Terminal
The PIC17C766/CL fits point-of-sale terminals because its 66 I/O pins drive a 4x4 keypad matrix, four-character 7-segment displays, and cash-drawer solenoids concurrently. The 32KB EPROM stores transaction state machines and price-lookup tables for small retail deployments. I2C interfaces with an external EEPROM that holds daily transaction logs, while the UART connects to a thermal receipt printer. The 902-byte RAM is sufficient to buffer 50-character product names and 16-digit totals without external memory. At 33MHz the MCU sustains the polling loop for keypad debouncing, display multiplexing, and printer handshaking inside one 121 ns instruction cycle. Although EPROM limits field updates, fixed-price retail kiosks benefit from the deterministic boot time and long-term code retention.
Recommended
Security Access Control System
The PIC17C766/CL fits security access control panels because its 66 I/O pins support 16-zone alarm inputs, 8 relay-controlled door strikes, and keypad readers across multiple doors. The 32KB EPROM stores credential tables for up to 1000 users along with audit trail logic, while the 902-byte RAM buffers time-stamped event records between log flushes. The I2C bus interfaces with a real-time clock for accurate timestamping, and SPI drives a 128x64 graphical LCD displaying door status. At 33MHz the 8.25 MIPS throughput scans all 16 zones within 10 ms, ensuring alarm response latency stays under 50 ms per IEC 62642 alarm-system timing recommendations. The /CL windowed package supports secure field re-credentialing via UV erasure, useful for high-security sites requiring periodic credential rotation.
Recommended
Automotive Body Electronics
The PIC17C766/CL fits automotive body electronics modules because its 66 I/O pins drive window lift motors, mirror adjusters, seat-position sensors, and lighting relays without external multiplexer ICs. The 32KB EPROM stores the seat-memory and keyless-entry state machines, while the 902-byte RAM buffers CAN-style message handling loops implemented over UART for legacy vehicles. At 33MHz the 8.25 MIPS throughput services 16 simultaneous PWM outputs for HVAC blend doors and mirror actuators, achieving 10-bit effective resolution at 100 Hz refresh. The EPROM's 20-year data retention exceeds typical vehicle service life, reducing warranty risk. Modern designs targeting post-2010 vehicles should evaluate PIC18F8520 or dsPIC33EP64MC504 for AEC-Q100 stress-test compliance and native CAN bus support.
Recommended
Legacy Industrial Embedded Board
The PIC17C766/CL fits legacy industrial embedded boards because its 84-CERQUAD J-lead footprint is shared with the PIC17C756A, PIC17C762, and PIC17C752 family members, allowing in-place memory upgrades or downgrades during board rework. The 32KB EPROM stores the firmware revision in non-volatile memory that survives 20+ years without battery backup, ideal for utility metering, factory-floor controllers, and railway signal modules that must boot reliably after long idle periods. The 902-byte RAM is sufficient for protocol stacks such as Modbus RTU over UART and basic sensor polling. At 33MHz the core provides 8.25 MIPS throughput, adequate for legacy deterministic control loops. Repair depots benefit from the windowed CERQUAD package because UV erasure allows firmware re-flashing without removing the MCU from the board's socket.
Recommended
Recommended Products Summary
Engineering reference data for PIC17C766/CL — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC17C762-33I/PT | PIC17C762-16I/PT | PIC17C756A-33E/PT | PIC17C756A-16I/PT | PIC17C752-33/PT |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 84-CERQUAD windowed (29.21x29.21 mm) | 84-pin CERQUAD / PT - same footprint | 84-pin CERQUAD / PT - same footprint | 84-pin CERQUAD / PT - same footprint | 84-pin CERQUAD / PT - same footprint | 84-pin CERQUAD / PT - same footprint |
| Program Memory | 32 KB (16K x 16) EPROM | 16 KB EPROM (-50%) | 16 KB EPROM (-50%) | 32 KB EPROM (same) | 32 KB EPROM (same) | 32 KB EPROM (same) |
| RAM Size | 902 bytes | 902 bytes (same) | 902 bytes (same) | 902 bytes (same) | 902 bytes (same) | 902 bytes (same) |
| Maximum Clock | 33 MHz | 33 MHz (same) | 16 MHz (-51%) | 33 MHz (same) | 16 MHz (-51%) | 33 MHz (same) |
| I/O Pins | 66 | 66 (same) | 66 (same) | 66 (same) | 66 (same) | 66 (same) |
| Serial Interfaces | I2C, SPI, UART/USART | I2C, SPI, UART/USART (same) | I2C, SPI, UART/USART (same) | I2C, SPI, UART/USART (same) | I2C, SPI, UART/USART (same) | I2C, SPI, UART/USART (same) |
| Package Type | Windowed CERQUAD (UV-erasable) | Plastic TQFP / CERQUAD | Plastic TQFP / CERQUAD | Plastic TQFP / CERQUAD | Plastic TQFP / CERQUAD | Plastic TQFP / CERQUAD |
Key Differentiators
- Full 32KB EPROM in the 84-CERQUAD package (vs PIC17C762-33I/PT)
- 33MHz full-speed operation (vs PIC17C756A-16I/PT)
- Highest-density pinout in the legacy PIC17C family (vs PIC17C752-33/PT)
Design Notes
The PIC17C766/CL is a windowed CERQUAD part intended for prototype development using UV erasure. For production builds, migrate to PIC17C756A-16I/PT or PIC18F8520 in plastic packaging to reduce cost and improve mechanical robustness. Estimate cost differential: windowed CERQUAD parts typically run 3-4x the price of plastic OTP equivalents at qty 1000.
When designing a PCB to accept the PIC17C766 family, use a Textool 84-pin CERQUAD socket (e.g., 3M Textool 284-84) for development so the part can be UV-erased and re-programmed without desoldering. Add 100nF ceramic decoupling capacitors on each VDD/VSS pair within 5mm of the pins, plus a 10uF tantalum bulk capacitor at the board entry point. The 33MHz clock trace from the crystal to OSC1/OSC2 should be kept under 10mm and routed over a continuous ground plane.
The PIC17C766's external oscillator input is sensitive to noise above 33MHz; route the crystal traces symmetrically with equal-length paths to OSC1 and OSC2, and place a ground guard ring around the oscillator cell. Estimated: at 33MHz fundamental, the third harmonic (99MHz) can radiate EMI if traces exceed 8mm. Use a 4-layer PCB with a solid ground plane beneath the oscillator area to suppress common-mode radiation. Verify oscillator start-up margin with the manufacturer-supplied oscillator validation spreadsheet.
Compliance Information
Windowed CERQUAD package is typically non-RoHS because of the gold-plated ceramic body and quartz window. Lead-free status 'no' reflects traditional CERQUAD construction; check distributor data sheets for current specific compliance certifications. AEC-Q100 not qualified - use PIC18F8520 or dsPIC33EP64MC504 for automotive.
