PIC16C55-RCI/P - 8-bit CMOS MCU 0.75KB ROM 20 I/O | Microchip
MPN: PIC16C55-RCI/P ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.95 | $9.95 |
| 10 | $8.95 | $89.50 |
| 100 | $7.5 | $750.00 |
| 500 | $6.2 | $3,100.00 |
| 1,000 | $5.1 | $5,100.00 |
PIC16C55-RCI/P Overview
A PIC microcontroller is a compact, self-contained computer-on-a-chip that integrates a CPU, non-volatile program memory, working RAM, digital I/O, and one or more timers onto a single die. The PIC16C5X family uses a 12-bit-wide instruction word and an 8-bit data path, achieving roughly 2:1 code compression versus typical 8-bit CISC microcontrollers. Within the broader taxonomy, this part belongs to microcontrollers -> 8-bit MCUs -> embedded controllers -> semiconductors, and serves as a predecessor to the modern flash-based PIC16F family.
Key features include an 8-bit real-time clock/counter (TMR0), a two-level hardware stack, direct/indirect/relative addressing, seven or eight special-function hardware registers, and a programmable code-protection bit. The device operates from a wide 2.5 V to 6.25 V supply, supports clock speeds up to 20 MHz (4 MHz RC variant), and offers power-saving Sleep mode with Wake-on-pin-change. The 28-pin PDIP footprint delivers 20 usable I/O lines after reserving VDD, VSS, OSC1, OSC2, MCLR, and the timer-0 pin.
The architecture is based on a RISC-style Harvard design with separate program and data buses, enabling simultaneous instruction fetch and operand access. Instruction pipelining overlaps fetch and execute cycles, so most instructions complete in one oscillator cycle except for program branches. The RC oscillator option eliminates the cost of an external crystal or resonator, reducing BOM cost for cost-sensitive appliance, toy, and consumer-electronics designs.
Typical applications include appliance controllers, HVAC fan and damper drivers, automotive body-electronics modules, simple sensor signal conditioning, RC servo drivers, and legacy industrial control boards. The wide operating voltage range and industrial temperature grade make it suitable for environments where regulated power and stable thermal behavior are required.
When designing with this device, plan for its 2-level stack - deeply nested subroutines will overflow the hardware stack, so engineers typically keep call depth shallow or convert to iterative code. For modern designs, consider migration to the flash-based PIC16F54 or PIC16F57, which offer the same 18-20 I/O count and 28-pin PDIP footprint but provide reprogrammability.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for PIC16C55-RCI/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-RCI/P (same form factor and footprint) — differing in Instruction Word Width, Package, Timers, Watchdog Timer, Core.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C55-RCE/P
✅ Drop-In✓ In Stock
$4.68 / Unit
View Datasheet →PIC16C55-HSI/P
✅ Drop-In✓ In Stock
$2.6 / Unit
View Datasheet →PIC16C55-LPI/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F54-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C55-10I/P
✅ Drop-In✓ In Stock
$2.58 / Unit
View Datasheet →PIC16C55-RCI/P Maximum Ratings & Electrical Characteristics
| Core | 8-bit PIC16C5X RISC |
| Program Memory | 0.75 KB ROM |
| RAM | 24 bytes |
| I/O Pins | 20 |
| Package | PDIP-28 (P) |
| Mounting Type | Through-Hole |
| Supply Voltage | 2.5 V to 6.25 V |
| Maximum Clock Frequency | 20 MHz |
| Instruction Word Width | 12 bits |
| Data Bus Width | 8 bits |
| Timers | 1 x 8-bit (TMR0) |
| Hardware Stack | 2 levels |
| Oscillator Mode | RC (external resistor/capacitor) |
| Operating Temperature | -40 C to +85 C (industrial) |
| Code Protection | Programmable |
| Sleep Mode | Yes |
| Watchdog Timer | No (this device) |
| ADC | None |
| RoHS Status | Non-compliant (PDIP, contains lead) |
PIC16C55-RCI/P Pin Configuration
| Pin 1 | RA2 — Port A bit 2 (digital I/O) |
| Pin 2 | RA3 — Port A bit 3 (digital I/O) |
| Pin 3 | T0CKI — Timer 0 clock input |
| Pin 4 | MCLR — Master Clear (reset, active low) |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0 — Port B bit 0 (digital I/O, interrupt-on-change) |
| Pin 7 | RB1 — Port B bit 1 (digital I/O, interrupt-on-change) |
| Pin 8 | RB2 — Port B bit 2 (digital I/O, interrupt-on-change) |
| Pin 9 | RB3 — Port B bit 3 (digital I/O, interrupt-on-change) |
| Pin 10 | RB4 — Port B bit 4 (digital I/O, interrupt-on-change) |
| Pin 11 | RB5 — Port B bit 5 (digital I/O, interrupt-on-change) |
| Pin 12 | RB6 — Port B bit 6 (digital I/O, interrupt-on-change) |
| Pin 13 | RB7 — Port B bit 7 (digital I/O, interrupt-on-change) |
| Pin 14 | VDD — Positive supply voltage (2.5 V to 6.25 V) |
| Pin 15 | OSC2/CLKOUT — Oscillator output / clock output |
| Pin 16 | OSC1/CLKIN — Oscillator input / external clock input |
| Pin 17 | RA0 — Port A bit 0 (digital I/O) |
| Pin 18 | RA1 — Port A bit 1 (digital I/O) |
| Pin 19 | RA4 — Port A bit 4 (digital I/O) |
| Pin 20 | RA5 — Port A bit 5 (digital I/O) |
| Pin 21 | RA6 — Port A bit 6 (digital I/O) |
| Pin 22 | RA7 — Port A bit 7 (digital I/O) |
| Pin 23 | RB0 — Port B bit 0 alternate (digital I/O) |
| Pin 24 | RB1 — Port B bit 1 alternate (digital I/O) |
| Pin 25 | RB2 — Port B bit 2 alternate (digital I/O) |
| Pin 26 | RB3 — Port B bit 3 alternate (digital I/O) |
| Pin 27 | RB4 — Port B bit 4 alternate (digital I/O) |
| Pin 28 | RB5 — Port B bit 5 alternate (digital I/O) |
Typical Applications
PIC16C55-RCI/P is suitable for 6 applications: Appliance Control Boards, Automotive Body Electronics, HVAC Fan and Damper Control, RC Servo and Toy Controllers, Industrial Sensor Signal Conditioning, LED Display and Sign Controllers.
Appliance Control Boards
The PIC16C55-RCI/P suits washing-machine timer controllers, microwave oven user-interface boards, and dishwasher cycle controllers because its 0.75 KB ROM and 24 bytes RAM are sufficient for fixed-sequence state machines. Its industrial -40 C to +85 C temperature range and wide 2.5 V to 6.25 V supply let it run directly from a rectified 5 V or 3.3 V rail. The 20 mA source/sink on each of the 20 I/O pins drives LEDs, relays, and triac interfaces directly without buffer transistors, simplifying BOM and reducing cost. RC oscillator mode eliminates the crystal, further reducing bill-of-materials cost. Compared with a discrete 555-timer + CMOS-logic design, this single-chip MCU replaces dozens of components and adds programmability for product differentiation.
Recommended
Automotive Body Electronics
Inside interior lighting controllers, simple window-lift modules, and seat-position memory, the PIC16C55-RCI/P's 20 I/O pins interface with switches, LEDs, and H-bridge MOSFET drivers. Its industrial temperature grade handles under-dash thermal conditions, and its wide operating voltage survives load-dump transients on the 12 V automotive bus when paired with an external TVS diode. The two-level hardware stack keeps interrupt latency deterministic for safety-critical signaling. For new automotive designs the AEC-Q100-qualified PIC16F54-I/P would be the modern replacement, but the legacy PIC16C55-RCI/P remains in millions of vehicles on the road.
Recommended
HVAC Fan and Damper Control
In heating, ventilation, and air-conditioning systems, the PIC16C55-RCI/P runs the multi-speed blower controller and motorized damper logic that distributes conditioned air through ducts. Its RC oscillator eliminates crystal cost in cost-sensitive residential HVAC equipment. The hardware timers and interrupt-on-change wake-up from Sleep mode deliver responsive user-interface feedback while keeping standby current below 1 mA, important for ENERGY STAR-rated thermostats. The 0.75 KB code space hosts a complete control loop, keypad scan, and seven-segment display driver, replacing legacy 8051 designs at lower cost.
Recommended
RC Servo and Toy Controllers
RC servos, electronic speed controllers for toy-grade drones, and animatronic figures rely on the PIC16C55-RCI/P's precise TMR0 counter to generate 50 Hz PWM pulses with 1-2 ms pulse-width control. The 20 I/O pins drive multiple servos simultaneously, and the wide 2.5-6.25 V supply lets the device run directly from a 4-cell NiMH or 2S Li-ion pack. The RC oscillator calibrates via firmware timing loops, reducing per-unit crystal cost across high-volume toy production runs. With 768 bytes of code the MCU can implement stabilization, mixing, and simple failsafe behaviors in a single chip.
Recommended
Industrial Sensor Signal Conditioning
For limit-switch debouncers, photoelectric-sensor pulse counters, and conveyor tachometers, the PIC16C55-RCI/P provides reliable counting and on/off control in a 28-pin PDIP that mounts easily on DIN-rail backplane boards. Its industrial -40 C to +85 C operating temperature ensures stable operation in factory floors and outdoor enclosures. The wide supply tolerance tolerates unregulated 24 V industrial rails when paired with a 7805 regulator. Code protection prevents reverse-engineering of proprietary counting algorithms, while the two-level hardware stack keeps interrupt latency low for high-speed pulse counting above 50 kHz.
Recommended
LED Display and Sign Controllers
Small scrolling LED message boards, scoreboard controllers, and 7-segment panel drivers use the PIC16C55-RCI/P to multiplex 8-16 digits of LEDs while scanning a 4x4 keypad for user input. The 20 mA source/sink per I/O pin directly drives common-anode LED cathodes through current-limiting resistors, eliminating driver transistors. Multiplexed refresh rates above 100 Hz appear flicker-free to the human eye. Code-protection locks the message-storage algorithm to prevent unauthorized modification. RC oscillator mode allows the board to operate from any supply between 2.5 V and 6.25 V without precision timing reference.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C55-RCI/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C55-RCE/P | PIC16C55-HSI/P | PIC16C55-LPI/P | PIC16F54-I/P | PIC16C55-10I/P |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | PDIP-28 | PDIP-28 - same | PDIP-28 - same | PDIP-28 - same | PDIP-28 - same | PDIP-28 - same |
| Program Memory | 0.75 KB ROM | 0.75 KB ROM | 0.75 KB ROM | 0.75 KB ROM | 0.5 KB Flash (reprogrammable) | 0.75 KB ROM |
| RAM | 24 bytes | 24 bytes | 24 bytes | 24 bytes | 25 bytes | 24 bytes |
| I/O Pins | 20 | 20 | 20 | 20 | 18 | 20 |
| Maximum Clock | 4 MHz (RC mode) | 4 MHz (RC mode) | 20 MHz (HS crystal mode) | 200 kHz (LP crystal mode) | 20 MHz | 10 MHz |
| Operating Voltage | 2.5 V to 6.25 V | 2.5 V to 6.25 V | 2.5 V to 6.25 V | 2.5 V to 6.25 V | 2.0 V to 5.5 V | 2.5 V to 6.25 V |
| Memory Type | One-Time-Programmable ROM | One-Time-Programmable ROM | One-Time-Programmable ROM | One-Time-Programmable ROM | Flash (reprogrammable, 1000 cycles) | One-Time-Programmable ROM |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Active (recommended for new designs) | Obsolete |
Key Differentiators
- Flash reprogrammability on same footprint (vs PIC16F54-I/P)
- Higher clock rate on same footprint (vs PIC16C55-HSI/P)
- Lower-power operation on same footprint (vs PIC16C55-LPI/P)
- Production-ready active lifecycle (vs PIC16F54-I/P)
Design Notes
PIC16C55-RCI/P supply voltage range is 2.5 V to 6.25 V with internal brown-out not available on this baseline family. Place a 100 nF decoupling capacitor within 5 mm of the VDD pin (pin 14) and a 10 uF bulk capacitor at the PCB power-entry point. For battery applications, RC oscillator calibration must compensate for VDD variation because RC frequency shifts 5-10 percent across the supply range, requiring software-trimmed timing loops rather than fixed delays.
PIC16C55 has only a 2-level hardware stack. Subroutines nested deeper than 2 levels will overwrite the return PC and cause code to execute at unpredictable addresses. Restructure nested calls as iterative loops or unroll them inline. Additionally, the OPTION register TRM0 source selection controls whether TMR0 increments from the internal instruction clock or the external T0CKI pin (pin 3); incorrect configuration silently disables timer interrupts without fault indication.
Route the MCLR (pin 4) trace directly to the reset circuit with no stubs. Place the MCLR pull-up resistor (typically 10 kohm) within 5 mm of pin 4. If using an RC oscillator, keep the R/C network leads short and away from switching traces to minimize EMI injection into the clock; the RC oscillator is more sensitive to coupling than a crystal-based design. Add a 100 nF bypass on VDD near pin 14 and a guard ring around the oscillator node.
Each PIC16C55 I/O pin can source or sink 20 mA continuously but the total VDD current is limited to 150 mA across all pins. When driving 8+ LEDs directly, calculate the worst-case per-pin sum and confirm it stays below 150 mA, otherwise LEDs will dim and the die will heat. For higher drive, buffer with a ULN2803 or discrete transistor array. PORTB interrupt-on-change pins (RB0-RB7) require software-debounced inputs to avoid spurious interrupts from mechanical switches.
Compliance Information
PDIP-28 package contains lead (SnPb or pure Sn lead finish depending on date code); not RoHS-compliant in the strict sense. REACH compliant per Microchip product disclosures. Not AEC-Q100 qualified - choose PIC16F54-I/P or PIC16C55A variants for automotive applications.
