PIC16C55-10/P - 8-bit OTP MCU, 10MHz, 20 I/O, PDIP-28 | Microchip
MPN: PIC16C55-10/P ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.73 | $5.73 |
| 10 | $5.15 | $51.50 |
| 100 | $4.59 | $459.00 |
| 500 | $4.1 | $2,050.00 |
| 1,000 | $3.65 | $3,650.00 |
PIC16C55-10/P Overview
A microcontroller (MCU) is a single-chip computer containing a CPU core, program memory, working RAM, and peripheral interfaces. Within the semiconductor taxonomy, a microcontroller is a sub-category of integrated circuits (ICs), and the PIC16C5x sits in the OTP-programmable low-end 8-bit segment. The PIC16C5x architecture uses a Harvard layout with separate program and data buses, a two-level deep hardware stack, and direct/indirect/relative addressing modes, enabling compact code density and deterministic interrupt response for simple control loops.
Key features include 12-bit wide instructions, 8-bit data path, seven or eight special-function hardware registers, a two-level hardware stack, a single 8-bit real-time clock/counter (TMR0), and an operating supply range of 4.5 V to 5.5 V. The 10 MHz oscillator speed grade and 4.5 V to 5.5 V VDD range target 5 V industrial and consumer designs that predate the modern 3.3 V MCU ecosystem. The 20 I/O pins are TTL/CMOS-compatible and can source/sink typical CMOS drive currents, making the part drop-in compatible with classic PIC16C5x layouts.
The PIC16C55-10/P uses a classic RISC-like instruction set of approximately 33 single-word/cycle instructions, with most instructions executing in one instruction cycle (4 clock periods). The architecture prioritizes deterministic execution, low cost, and ease of programming through EPROM/OTP, which made it a workhorse in the 1990s for appliances, automotive subsystems, and industrial timers. Compared with later PIC16F parts, this OTP variant is one-time-programmable and cannot be electrically erased, which is an important design consideration for prototype flows.
Typical applications include legacy industrial control boards, simple timer/counter subsystems, LED display drivers, appliance control boards, low-end security keypads, and drop-in replacements for 27-series EPROM microcontrollers in long-life OEM products. The 28-pin PDIP footprint is also convenient for breadboard prototyping, university teaching labs, and hobbyist retrocomputing projects that target the original PIC16C5x instruction set.
When designing with this device, plan the OTP programming workflow early because the part cannot be re-programmed: use a PIC16C5x-compatible programmer such as the MPLAB PM3, and order pre-programmed parts through Microchip's programming service for production. Ensure VDD stays within 4.5 V to 5.5 V and that the 20 I/O pins are not loaded beyond their source/sink ratings; add a 0.1 uF decoupling cap close to the VDD pin.
This page synthesizes distributor pricing, drop-in PIC16C5x family alternatives, and practical OTP-programming design notes not found in the manufacturer datasheet, helping engineers source, replace, and integrate the PIC16C55-10/P with confidence.
Drop-in alternatives for PIC16C55-10/P — 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 PIC16C55-10/P (same form factor and footprint) — differing in Package, Timers, Program Memory Size, Core Architecture, Program Memory Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C55-20/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C55-HS/P
✅ Drop-In✓ In Stock
$3.95 / Unit
View Datasheet →PIC16C55-XT/P
✅ Drop-In✓ In Stock
$4.05 / Unit
View Datasheet →PIC16C55-HSI/P
✅ Drop-In✓ In Stock
$2.6 / Unit
View Datasheet →PIC16F57-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C55/JW
✅ Drop-In✓ In Stock
$10.4 / Unit
View Datasheet →PIC16C55-10/P Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit PIC16C5x (Harvard, RISC-like) |
| Instruction Width | 12-bit |
| Data Path Width | 8-bit |
| Maximum Clock Frequency | 10 MHz |
| Program Memory Type | OTP (One-Time-Programmable) |
| Program Memory Size | 768 bytes (512 x 12) |
| RAM Size | 24 bytes |
| Number of I/O Pins | 20 |
| Timers | 1 x 8-bit (TMR0) |
| Hardware Stack | 2 levels |
| Supply Voltage (VDD) | 4.5 V to 5.5 V |
| Package | PDIP-28 (0.600 in, 15.24 mm) |
| Mounting Type | Through-Hole (THT) |
| Pin Count | 28 |
PIC16C55-10/P Pin Configuration
| Pin 1 | RA0 — Port A bit 0 (bidirectional digital I/O) |
| Pin 2 | RA1 — Port A bit 1 (bidirectional digital I/O) |
| Pin 3 | RA2 — Port A bit 2 (bidirectional digital I/O) |
| Pin 4 | RA3 — Port A bit 3 (bidirectional digital I/O) |
| Pin 5 | RA4/T0CKI — Port A bit 4 / Timer 0 clock input |
| Pin 6 | RB0 — Port B bit 0 (bidirectional digital I/O) |
| Pin 7 | RB1 — Port B bit 1 (bidirectional digital I/O) |
| Pin 8 | RB2 — Port B bit 2 (bidirectional digital I/O) |
| Pin 9 | RB3 — Port B bit 3 (bidirectional digital I/O) |
| Pin 10 | RB4 — Port B bit 4 (bidirectional digital I/O) |
| Pin 11 | RB5 — Port B bit 5 (bidirectional digital I/O) |
| Pin 12 | RB6 — Port B bit 6 (bidirectional digital I/O) |
| Pin 13 | RB7 — Port B bit 7 (bidirectional digital I/O) |
| Pin 14 | VSS — Ground reference |
| Pin 15 | RC0 — Port C bit 0 (bidirectional digital I/O) |
| Pin 16 | RC1 — Port C bit 1 (bidirectional digital I/O) |
| Pin 17 | RC2 — Port C bit 2 (bidirectional digital I/O) |
| Pin 18 | RC3 — Port C bit 3 (bidirectional digital I/O) |
| Pin 19 | RD0 — Port D bit 0 (bidirectional digital I/O) |
| Pin 20 | RD1 — Port D bit 1 (bidirectional digital I/O) |
| Pin 21 | RD2 — Port D bit 2 (bidirectional digital I/O) |
| Pin 22 | RD3 — Port D bit 3 (bidirectional digital I/O) |
| Pin 23 | RD4 — Port D bit 4 (bidirectional digital I/O) |
| Pin 24 | RD5 — Port D bit 5 (bidirectional digital I/O) |
| Pin 25 | RD6 — Port D bit 6 (bidirectional digital I/O) |
| Pin 26 | RD7 — Port D bit 7 (bidirectional digital I/O) |
| Pin 27 | VDD — Positive supply (4.5 V to 5.5 V) |
| Pin 28 | MCLR/VPP — Master clear reset (active low) / OTP programming voltage |
Typical Applications
PIC16C55-10/P is suitable for 6 applications: Legacy Industrial Control Boards, Simple Timer / Counter Subsystems, LED Display and Multiplexed Driver Boards, Appliance Control Boards, Security Keypad and Access Control Panels, Hobbyist Retrocomputing and Education.
Legacy Industrial Control Boards
The PIC16C55-10/P suits legacy industrial control boards originally designed around 5 V 8-bit PIC16C5x architectures. Its 20 I/O pins map directly to 5-port GPIO, 768B OTP holds typical 8-bit ladder-logic replacements, and 10 MHz execution supports millisecond control loops. The 28-pin PDIP footprint is convenient for replacement of EOL parts in long-life equipment. Designers can drop the OTP part onto existing pads and re-flash the program via MPLAB PM3, with no PCB rework. Compared to migrating to a 16-bit MCU, retaining the PIC16C5x core preserves legacy firmware investment.
Recommended
Simple Timer / Counter Subsystems
The PIC16C55-10/P's integrated 8-bit TMR0 hardware timer and 12-bit instruction set make it a natural fit for simple timer/counter subsystems in vending machines, lighting controllers, and irrigation valves. The 10 MHz clock yields 100 ns instruction cycles, sufficient for sub-microsecond event capture at T0CKI. With 20 I/O, four 8-bit ports (RA-RD) drive LEDs, relays, and zero-cross triac drivers without external glue logic. The OTP memory holds fixed timing schedules that never need firmware update in the field. The part's 4.5 V to 5.5 V range matches legacy 5 V power rails.
Recommended
LED Display and Multiplexed Driver Boards
The PIC16C55-10/P drives multiplexed 7-segment LED displays, dot-matrix panels, and bar-graph indicators using its 20 I/O pins as row/column drivers. With software PWM, it can dim individual LEDs without external driver ICs. The 10 MHz instruction rate supports refresh rates above 100 Hz, eliminating visible flicker on 8-digit displays. The 24-byte RAM is sufficient for storing display buffers in small arrays. The 28-pin PDIP package is convenient for through-hole display boards used in point-of-sale terminals and appliance front panels. OTP memory locks the display pattern at production, preventing field tampering.
Recommended
Appliance Control Boards
The PIC16C55-10/P is widely deployed in consumer appliance control boards (washing machines, microwaves, dishwashers) thanks to its 4.5 V to 5.5 V supply, 20 I/O for keypad/relay/buzzer, and OTP memory for fixed firmware. The 10 MHz speed handles motor-control state machines, sensor reading, and UI polling with margin. The 28-pin PDIP is mechanically robust for through-hole appliance PCBs that endure vibration. Microchip's long-term support commitment keeps the part active for 15+ year appliance lifecycles. Designers can implement wash-cycle profiles, lid-lock interlocks, and diagnostic blink codes in a single chip.
Recommended
Security Keypad and Access Control Panels
The PIC16C55-10/P reads 4x4 matrix keypads via its 20 I/O pins, debounces in software, drives piezo buzzers, and controls electric door strikes. The 10 MHz speed handles 5-10 ms debounce times and 50 ms user-feedback response comfortably. OTP memory prevents code extraction by attackers, a security plus for access control. The 28-pin PDIP is easy to assemble into small security panel PCBs. The 768B OTP accommodates 4-digit PIN comparison, EEPROM emulation in RAM, and tamper detection logic. Many off-the-shelf alarm panels from the late 1990s used the PIC16C5x family for these reasons.
Recommended
Hobbyist Retrocomputing and Education
The PIC16C55-10/P is a popular teaching tool in university embedded systems courses and hobbyist retrocomputing projects, because its 28-pin PDIP fits breadboards, the 12-bit instruction set is fully documented, and the part is widely available at low cost. Students learn RISC pipelining, OTP programming via MPLAB PM3, and 8-bit GPIO basics on a forgiving through-hole package. The 10 MHz speed grade matches textbook timing examples. Compared to modern Curiosity Nano boards, the PIC16C55-10/P teaches register-level programming without abstraction layers, building foundational embedded knowledge.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C55-10/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C55-20/P | PIC16C55-HS/P | PIC16C55-XT/P | PIC16C55-HSI/P | PIC16F57-I/P | PIC16C55/JW |
|---|---|---|---|---|---|---|---|
| Package | PDIP-28 | PDIP-28 - same | PDIP-28 - same | PDIP-28 - same | PDIP-28 - same | PDIP-28 - same | CERDIP-28 (windowed) - pin-compatible |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Core | 8-bit PIC16C5x | 8-bit PIC16C5x | 8-bit PIC16C5x | 8-bit PIC16C5x | 8-bit PIC16C5x | 8-bit PIC16F5x (flash) | 8-bit PIC16C5x |
| Max Clock Frequency | 10 MHz | 20 MHz | 20 MHz | 4 MHz | 20 MHz | 20 MHz | 20 MHz |
| Program Memory | 768 B (512 x 12) OTP | 768 B (512 x 12) OTP | 768 B (512 x 12) OTP | 768 B (512 x 12) OTP | 768 B (512 x 12) OTP | 2 KB (1k x 14) Flash | 768 B (512 x 12) UV EPROM |
| RAM | 24 B | 24 B | 24 B | 24 B | 24 B | 72 B | 24 B |
| I/O Pins | 20 | 20 | 20 | 20 | 20 | 20 | 20 |
| Memory Type | OTP (one-time programmable) | OTP | OTP | OTP | OTP | Flash (reprogrammable) | UV-erasable EPROM (windowed) |
| Supply Voltage | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 2.0 V to 5.5 V | 4.5 V to 5.5 V |
| Oscillator Mode | External (XT/HS compatible) | External | External HS | External XT | Internal RC | External or internal RC | External |
Key Differentiators
- Same-package drop-in with 2x higher clock speed (vs PIC16C55-20/P)
- Flash memory for development and in-field updates (vs PIC16F57-I/P)
- UV-erasable windowed variant for prototype iteration (vs PIC16C55/JW)
Design Notes
The PIC16C55-10/P must be powered from a regulated 4.5 V to 5.5 V rail. Place a 0.1 uF ceramic decoupling capacitor as close as possible to the VDD pin (pin 27) with a short trace, plus a 10 uF bulk capacitor near the regulator. The MCLR/VPP pin (pin 28) should be tied to VDD through a 10 kohm pull-up for normal operation, and a 100 nF cap to ground for noise filtering on the reset line. Estimated: IIDLE approx. 5 uA and IDD active approx. 2 mA at 10 MHz per the PIC16C5x datasheet typical curves.
The PIC16C55-10/P uses One-Time-Programmable (OTP) memory, so once programmed the firmware cannot be changed. Plan the development flow with a PIC16C55/JW windowed CERDIP part (or PIC16F57-I/P flash equivalent) for development, then move to PIC16C55-10/P for production. Also note that the 4.5 V to 5.5 V supply is mandatory - the part will not operate reliably below 4.5 V. The 20 I/O pins have a source/sink current of typically 20 mA per pin, but the total package dissipation must not exceed 800 mW.
Use a 4-layer PCB if possible, with a continuous ground plane beneath the IC and short traces on the oscillator pins (pins 15-16 for OSC1/OSC2 on the PIC16C5x). Keep the clock traces away from high-current switching signals and add a guard ring around the crystal. Place the VDD bypass cap (0.1 uF) within 5 mm of pin 27, and add a ferrite bead on the supply rail if the design is in a noisy industrial environment. The 28-pin PDIP footprint matches standard 0.600 in row spacing - no special footprint rules apply.
The PIC16C55-10/P has no internal oscillator, so the external crystal or resonator must be chosen to match the 10 MHz speed grade. A 10 MHz AT-cut fundamental-mode crystal with 20 pF load capacitance is the typical choice for the -10 (XT) variant. If using a ceramic resonator, account for its wider initial tolerance (+/- 0.5%) versus crystal (+/- 50 ppm). The T0CKI pin (pin 5) can be used for external event counting - add a 100 ohm series resistor to limit ringing on fast edges.
Compliance Information
PIC16C55-10/P is the SnPb lead-finish variant; Microchip offers a lead-free /P variant (e.g., -10E/P suffix) for RoHS-compliant designs. AEC-Q100 qualification is not applicable for this 5 V industrial-grade part.
