PIC16C56-RC/SO - 8-Bit 4MHz OTP MCU, 1.5KB | Microchip
MPN: PIC16C56-RC/SO β End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.88 | $4.88 |
| 10 | $4.39 | $43.90 |
| 100 | $3.69 | $369.00 |
| 500 | $3.1 | $1,550.00 |
| 1,000 | $2.62 | $2,620.00 |
PIC16C56-RC/SO Overview
A microcontroller (MCU) is a single-chip computer containing a CPU, program memory, working RAM, and configurable I/O peripherals. The PIC16C5X family belongs to Microchip's original baseline RISC 8-bit architecture, employing only 33 single-word/single-cycle instructions to deliver 2:1 code compression over competing 8-bit MCUs in its class. This particular variant uses an RC oscillator input, allowing designers to set the system clock with a simple external resistor and capacitor β a low-cost timing solution for non-critical timing applications.
Key features include a 12-bit-wide instruction word, 8-bit-wide data path, seven or eight Special Function Registers (SFRs), a two-level-deep hardware stack, and direct/indirect/relative addressing modes. An 8-bit Timer0 (TMR0) with a prescaler provides real-time event counting and basic periodic interrupt capability. The 12 I/O pins are arranged as PORTA and PORTB, each capable of driving CMOS or TTL loads. The integrated Power-on Reset (POR), Watchdog Timer (WDT), and code-protection features support reliable standalone operation. The RC oscillator variant ("RC" in the part number) trades the precision of a crystal for a lower BOM cost and faster power-on.
Architecturally, the PIC16C56 employs a Harvard design that separates program and data buses, allowing instruction fetch and data access to occur in the same cycle. This, combined with the 12-bit opcode width and 33-instruction RISC set, results in deterministic interrupt latency and compact code density. The 4 MHz instruction rate (1 MIPS) is sufficient for slow control loops, human-interface button debouncing, sensor sampling at sub-kHz rates, and simple LED multiplexing.
Typical applications include low-cost consumer appliances, appliance remote controls, LED display drivers, simple sensor interfaces, battery-powered toys, and replacement of discrete logic in legacy designs. Designers choose the PIC16C56-RC/SO when cost per unit is the deciding factor, the application tolerates RC-oscillator frequency tolerance, and OTP programming for production is acceptable.
When designing with this part, calculate the worst-case supply current from the datasheet DC characteristics and ensure the external RC component values stay within the manufacturer's recommended ranges for stable oscillation across temperature. Note that the OTP memory can be programmed only once, so production code must be fully validated before device programming.
This page synthesizes distributor pricing, drop-in alternatives within the PIC16C5X family, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for PIC16C56-RC/SO β 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 PIC16C56-RC/SO (same form factor and footprint) β differing in Oscillator Type, Program Memory Type, RAM Size, Connectivity, Maximum Clock Frequency.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC16C56-LP/SO
β Drop-Inβ In Stock
$1.82 / Unit
View Datasheet βPIC16C56-HSI/SO
β Drop-Inβ In Stock
$1.83 / Unit
View Datasheet βPIC16C56T-RC/SO
β Drop-Inπ Reference alternative (not in catalog)
PIC16C56-RCS/SO
β Drop-Inπ Reference alternative (not in catalog)
PIC16C56-RCE/SO
β Drop-Inβ In Stock
$1.85 / Unit
View Datasheet βPIC16C56-RC/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC |
| Program Memory Type | OTP (One-Time-Programmable EPROM) |
| Program Memory Size | 1.5 KB (1K x 12) |
| RAM Size | 25 bytes |
| Maximum CPU Frequency | 4 MHz |
| Instruction Set Width | 12-bit |
| Number of Instructions | 33 |
| I/O Pins | 12 |
| Timers | 1 x 8-bit (TMR0 with prescaler) |
| Stack Depth | 2 levels (hardware) |
| Oscillator Type | External RC |
| Supply Voltage Range | 3.0 V to 6.25 V |
| Operating Temperature Range | -40C to +85C (industrial) |
| Package | 18-pin SOIC (SO) |
| Mounting Type | Surface Mount |
PIC16C56-RC/SO Pin Configuration
| Pin 1 | RA2 β PORTA bit 2 (bidirectional digital I/O) |
| Pin 2 | RA3 β PORTA bit 3 (bidirectional digital I/O) |
| Pin 3 | RA4/T0CKI β PORTA bit 4 / Timer0 clock input (bidirectional digital I/O, open-drain output) |
| Pin 4 | MCLR/Vpp β Master Clear reset input / programming voltage input |
| Pin 5 | VSS β Ground reference |
| Pin 6 | RB0/INT β PORTB bit 0 / external interrupt input (bidirectional digital I/O) |
| Pin 7 | RB1 β PORTB bit 1 (bidirectional digital I/O) |
| Pin 8 | RB2 β PORTB bit 2 (bidirectional digital I/O) |
| Pin 9 | RB3 β PORTB bit 3 (bidirectional digital I/O) |
| Pin 10 | RB4 β PORTB bit 4 (bidirectional digital I/O) |
| Pin 11 | RB5 β PORTB bit 5 (bidirectional digital I/O) |
| Pin 12 | RB6 β PORTB bit 6 (bidirectional digital I/O) |
| Pin 13 | RB7 β PORTB bit 7 (bidirectional digital I/O) |
| Pin 14 | VDD β Positive supply voltage (3.0 V to 6.25 V) |
| Pin 15 | OSC2/CLKOUT β Oscillator output / clock output (Fosc/4) |
| Pin 16 | OSC1/CLKIN β Oscillator input / external clock input (RC network for -RC variant) |
| Pin 17 | RA0 β PORTA bit 0 (bidirectional digital I/O) |
| Pin 18 | RA1 β PORTA bit 1 (bidirectional digital I/O) |
Typical Applications
PIC16C56-RC/SO is suitable for 6 applications: Low-Cost Consumer Appliance Control, Battery-Powered Toy and Hobby Electronics, LED Display and Chaser Drivers, Replacement of Discrete Logic in Legacy Designs, Simple Sensor Interface and Signal Conditioning, IR Remote Control Transmitter.
Low-Cost Consumer Appliance Control
The PIC16C56-RC/SO is purpose-built for high-volume, cost-sensitive consumer appliances where its 1.5 KB of OTP memory easily accommodates fixed-function firmware: washing-machine timer logic, microwave keypad decoding, fan-speed control, rice-cooker thermal sequencing, and similar appliance embedded control loops. The 12 I/O pins directly drive relay coils, triac gate interfaces, LED indicators, and matrix keypads. The external RC oscillator eliminates the crystal, lowering BOM cost by ~USD 0.20-0.30 per unit, which is meaningful at appliance production volumes above 100k pieces per year. According to the Microchip PIC16C5X datasheet, the 4 MHz instruction rate is sufficient for slow control loops at sub-millisecond resolution.
Recommended
Battery-Powered Toy and Hobby Electronics
Toy and hobby applications benefit from the PIC16C56-RC/SO's ability to run from two alkaline cells (3.0 V nominal) with the supply range extending down to 3.0 V. The 25-byte RAM and 1.5 KB OTP are sufficient to implement motor PWM, sound playback bit-banging, LED chasing patterns, and IR remote control transmitters. The low pin count (12 I/O) keeps the PCB compact β ideal for thin-form-factor toys, educational kits, and hobby robotics controllers. The RC oscillator's typical Β±20% frequency tolerance is acceptable for sound and motor timing because human perception tolerates the resulting pitch and speed jitter.
Recommended
LED Display and Chaser Drivers
The PIC16C56-RC/SO is well-suited to LED chaser and marquee driving because its 12 I/O pins can drive 12 LEDs directly (each capable of sourcing 20 mA per the Microchip datasheet) or scan a larger multiplexed matrix. With software-driven Charlieplexing, a single PIC16C56 can address up to ~30 LEDs using just 6 I/O pins, leaving the remaining pins for mode buttons and brightness sensing. The 4 MIPS-instruction-budget supports smooth animation at 30-60 Hz refresh rates even when bit-banging multiple PWM channels. The compact 18-SOIC package fits easily into slim LED-strip controller enclosures.
Recommended
Replacement of Discrete Logic in Legacy Designs
Engineers modernizing legacy discrete-TTL or CMOS logic designs can replace dozens of 74-series gates with a single PIC16C56-RC/SO, reducing PCB area, power consumption, and assembly cost. The 33-instruction RISC set is far easier to maintain than hand-traced logic diagrams, and the OTP memory allows factory-programmed configuration per product SKU without DIP-switch or jumper customization. The 18-SOIC footprint is footprint-compatible with many legacy 74HC-series 20-SOIC designs (with appropriate trace rework), and the 3.0V to 6.25V supply range accommodates both 3.3V and 5V legacy rails without level translators.
Recommended
Simple Sensor Interface and Signal Conditioning
For simple sensor interfacing β thermistor voltage dividers, photoresistor light sensors, mechanical switch debouncing, Hall-effect sensors, and reed switches β the PIC16C56-RC/SO provides 12-bit-equivalent timing precision at 4 MHz, an 8-bit Timer0 for periodic sampling, and direct digital I/O for sensor readout. Although this baseline part lacks an integrated ADC, designers can implement single-slope or delta-sigma AD converters in firmware using one analog comparator pin and a known RC timing reference. The 25-byte RAM accommodates rolling-average filters for noise reduction, and the Watchdog Timer protects unattended installations.
Recommended
IR Remote Control Transmitter
Consumer IR remote controls (TVs, set-top boxes, fans, lighting, and audio equipment) are a classic PIC16C56-RC/SO application. The 4 MHz instruction rate generates standard 38 kHz / 40 kHz / 56 kHz carrier frequencies via bit-banged PWM with precise timing. The 25-byte RAM holds the most recent button-press state and protocol frame buffer; the 1.5 KB OTP accommodates NEC, RC5, SIRC, and proprietary protocol encoders. Battery life benefits from the 3.0V operation on two coin cells or alkaline AAs, and the 12 I/O pins scan a 3x4 or 4x4 keypad matrix with diode isolation.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C56-RC/SO β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C56-LP/SO | PIC16C56-HSI/SO | PIC16C56T-RC/SO | PIC16C56-RCS/SO | PIC16C56-RCE/SO |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 18-SOIC | 18-SOIC - same | 18-SOIC - same | 18-SOIC - same | 18-SOIC - same | 18-SOIC - same |
| Program Memory | 1.5 KB OTP | 1.5 KB OTP | 1.5 KB OTP | 1.5 KB OTP | 1.5 KB OTP | 1.5 KB OTP |
| RAM Size | 25 bytes | 25 bytes | 25 bytes | 25 bytes | 25 bytes | 25 bytes |
| Maximum Clock Frequency | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz |
| Oscillator Type | External RC | External LP crystal | External HS crystal | External RC (identical to this part) | External RC | External RC |
| Supply Voltage Range | 3.0 V to 6.25 V | 2.0 V to 6.25 V (wider, low-power) | 3.0 V to 6.25 V | 3.0 V to 6.25 V | 3.0 V to 6.25 V | 3.0 V to 6.25 V |
| Operating Temperature Range | -40C to +85C (industrial) | -40C to +85C (industrial) | -40C to +85C (industrial) | -40C to +85C (industrial) | -40C to +85C (industrial) | -40C to +125C (extended) |
| Typical Supply Current (active @ 4 MHz, 5 V) | ~2 mA (RC variant) | ~1 mA (low-power die) | ~2 mA | ~2 mA (same die) | ~2 mA | ~2 mA |
Key Differentiators
- External RC oscillator reduces BOM cost vs crystal-based -XT/-HS variants (vs PIC16C56-XT/SO)
- Drop-in compatibility with the entire PIC16C5X 18-SOIC family (vs PIC16F506-I/SL)
- Industrial temperature grade -40C to +85C standard (vs PIC16C56-RCE/SO)
Design Notes
Place the external RC timing components (resistor from Vdd to OSC1/CLKIN and capacitor from OSC1/CLKIN to Vss) as physically close to pins 16 and 5 as possible, with short, direct traces. Keep the RC traces away from any high-current switching nodes, relay coils, or oscillator pins of other ICs to avoid clock-frequency modulation by stray coupling. Add a 100 nF decoupling capacitor from Vdd (pin 14) to Vss (pin 5), routed with a wide, short trace and placed within 5 mm of the Vdd pin. According to the Microchip PIC16C5X datasheet, the recommended RC values are typically 3-100 kΞ© and 20 pF or greater, but consult the datasheet's RC oscillator table for the exact R/R range corresponding to your target frequency.
Estimated: The PIC16C56-RC/SO can only be programmed once β OTP memory cannot be erased. Use a windowed PIC16C56 (PIC16C56/JW, ceramic-windowed CERDIP package, which is on the XAIPART Site MPN list) for prototype development so you can erase with UV light. Do not exceed Vdd of 6.25 V (the absolute-maximum rating per the Microchip datasheet) β even brief over-voltage transients above ~7 V can permanently damage the device. Add a clamping TVS or Zener on Vdd if the supply is unregulated, and always include bulk decoupling. Finally, ensure the MCLR pin (pin 4) is tied to Vdd through a 10 kΞ© resistor for normal operation; leaving MCLR floating can result in intermittent resets from noise.
The PIC16C56-RC oscillator's frequency tolerance is typically Β±20% to Β±30% over the full industrial temperature range and across the 3.0V to 6.25V supply range, per the Microchip PIC16C5X datasheet RC-oscillator characterization curves. If your application requires tighter timing (UART bit timing, infrared carrier frequency, or audio tone accuracy), choose the -XT (crystal) or -HS (high-speed crystal) variant instead β these deliver Β±0.005% or better accuracy with a properly specified crystal. For UART emulation via software bit-banging, the RC tolerance translates directly into bit-error rate; budget at least 10% of the bit period as jitter and add start-bit oversampling to recover.
Compliance Information
RoHS, REACH, lead-free, and halogen-free status are not listed in the verified distributor data for PIC16C56-RC/SO. The PIC16C5X family pre-dates widespread RoHS adoption; engineers should request a compliance certificate directly from Microchip. AEC-Q100 qualification is not applicable for this industrial-grade baseline MCU; the -RCE extended-temperature variant is the closest automotive option but is still not formally AEC-Q100 qualified.