PIC16C56-RCI/SO - 8-bit EPROM MCU, 12 I/O, SOIC-18 | Microchip
MPN: PIC16C56-RCI/SO ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.85 | $1.85 |
| 10 | $1.62 | $16.20 |
| 100 | $1.4 | $140.00 |
| 500 | $1.18 | $590.00 |
| 1,000 | $0.99 | $990.00 |
PIC16C56-RCI/SO Overview
An 8-bit CMOS microcontroller (MCU) is a single-chip computer that integrates a CPU, memory, and peripherals on one die. The PIC16C5X family belongs to the high-performance, fully-static EPROM/ROM-based CMOS microcontroller hierarchy, which sits under the broader class of microcontrollers and embedded processors within the semiconductor taxonomy. These devices deliver an order-of-magnitude higher performance than competitors in the same price category thanks to the 12-bit wide instruction set that produces 2:1 code compression over other 8-bit MCUs in its class.
Key features include seven or eight special-function hardware registers, a two-level deep hardware stack, and direct, indirect, and relative addressing modes for both data and instructions. The PIC16C56 integrates an 8-bit real-time clock/counter (TMR0), watchdog timer, and EPROM program memory. The 'RCI' suffix designates the RC oscillator variant with industrial temperature grade, while '/SO' denotes the SOIC-18 package and tube media.
The architecture uses a RISC instruction set with only 33 single-cycle instructions, enabling deterministic interrupt response and tight code density. With 1.5 KB of EPROM program memory and 25 bytes of RAM, the device targets cost-sensitive embedded applications. The EPROM cell technology allows one-time-programmable (OTP) customization at production time, while a JW (windowed) ceramic variant is available for prototype development.
Typical applications include appliance control, low-end automotive subsystems, sensor signal conditioning, and simple embedded logic replacement. The wide operating voltage and RC oscillator tolerance make it well suited to cost-driven white goods, hobby electronics, and educational platforms where an external crystal is undesirable.
When designing with the PIC16C56-RCI/SO, engineers should note that the PIC16C56 family is designated 'Not Recommended for new designs' by Microchip, so it should be specified only for maintenance of legacy systems. New designs should consider the flash-based PIC16F or enhanced mid-range PIC16F1XX families as pin-compatible modern replacements.
This page synthesizes distributor pricing, parametric cross-reference data, and practical design notes drawn from real component databases to support both maintenance engineers sourcing legacy parts and procurement teams validating second-source supply for end-of-life inventory.
Drop-in alternatives for PIC16C56-RCI/SO — 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-RCI/SO (same form factor and footprint) — differing in Core Architecture, Package, RoHS Status, Oscillator Type, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C56-RC/P
✅ Drop-In✓ In Stock
$4.65 / Unit
View Datasheet →PIC16C56-LPI/SO
✅ Drop-In✓ In Stock
$1.31 / Unit
View Datasheet →PIC16C56-LPE/SO
✅ Drop-In✓ In Stock
$2.18 / Unit
View Datasheet →PIC16C56-LP/SO
✅ Drop-In✓ In Stock
$1.82 / Unit
View Datasheet →PIC16C56-HSI/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C56-HS/SS
✅ Drop-In✓ In Stock
$1.62 / Unit
View Datasheet →PIC16C56-RCI/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit PIC16 RISC |
| Instruction Width | 12-bit |
| Program Memory | 1.5 KB EPROM (OTP) |
| RAM | 25 bytes |
| I/O Pins | 12 |
| Operating Voltage | 3.3 V / 5 V |
| Oscillator Type | RC (internal/external RC network) |
| Timer | 8-bit TMR0 with prescaler |
| Stack Depth | 2 levels (hardware) |
| Addressing Modes | Direct, Indirect, Relative |
| Special Function Registers | 7 to 8 hardware registers |
| Package | SOIC-18 (SO) |
| Terminal Form | Gull Wing |
| Operating Temperature | -40 C to +85 C (Industrial) |
| Mounting Type | Surface Mount |
| Tube Packaging | Yes (per FindIC description) |
| Lifecycle Status | Not Recommended for new designs (NRND) |
| RoHS Status | Compliant (per icsuns listing) |
PIC16C56-RCI/SO Pin Configuration
| Pin 1 | RA2 — Port A bit 2 / bidirectional I/O |
| Pin 2 | RA3 — Port A bit 3 / bidirectional I/O |
| Pin 3 | RTCC — Real-Time Clock/Counter input (TMR0) |
| Pin 4 | MCLR — Master Clear reset (active low) |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0 — Port B bit 0 / bidirectional I/O |
| Pin 7 | RB1 — Port B bit 1 / bidirectional I/O |
| Pin 8 | RB2 — Port B bit 2 / bidirectional I/O |
| Pin 9 | RB3 — Port B bit 3 / bidirectional I/O |
| Pin 10 | RB4 — Port B bit 4 / bidirectional I/O |
| Pin 11 | RB5 — Port B bit 5 / bidirectional I/O |
| Pin 12 | RB6 — Port B bit 6 / bidirectional I/O |
| Pin 13 | RB7 — Port B bit 7 / bidirectional I/O |
| Pin 14 | VDD — Positive supply voltage (3.3V or 5V) |
| Pin 15 | OSC2 — Oscillator output / RC network connection |
| Pin 16 | OSC1 — Oscillator input / RC network connection |
| Pin 17 | RA0 — Port A bit 0 / bidirectional I/O |
| Pin 18 | RA1 — Port A bit 1 / bidirectional I/O |
Typical Applications
PIC16C56-RCI/SO is suitable for 6 applications: White Goods Appliance Control, Low-End Automotive Body Subsystems, Hobby Electronics and Educational Platforms, Sensor Signal Conditioning and Threshold Detection, Industrial Logic Replacement and Sequencers, Simple Embedded Logic Replacement (Glue Logic MCU).
White Goods Appliance Control
The PIC16C56-RCI/SO suits white-goods appliance control boards where cost dominates design decisions and 12 I/O pins are sufficient for switch sensing, relay drivers, and LED indicators. Its 1.5 KB EPROM holds typical washing-machine, dishwasher, or microwave firmware that drives a TRIAC for the load and reads mechanical buttons. Operating from 3.3V or 5V with RC oscillator tolerance simplifies the analog supply design because no crystal is required, lowering BOM cost.
Recommended
Low-End Automotive Body Subsystems
The PIC16C56-RCI/SO fits low-end automotive body controllers such as simple lighting timers, seat-position encoders, and auxiliary accessory drivers where 1.5 KB of code is sufficient. Its RC oscillator tolerance accommodates battery-voltage variation during cranking, and the industrial temperature grade covers under-dash environments. Migration to flash-based PIC16F5X parts is recommended for any new automotive design win because of Microchip's NRND classification for the EPROM C5X family.
Recommended
Hobby Electronics and Educational Platforms
The PIC16C56-RCI/SO is well suited to hobby electronics and educational microcontroller training boards that demonstrate embedded concepts without the complexity of modern peripherals. Its 12-bit wide instruction set and 33-instruction RISC core provide an approachable architecture for teaching register-level programming, while the 1.5 KB EPROM holds representative coursework projects. The RC oscillator option eliminates crystal cost, which keeps educational lab kit prices low for student adoption.
Recommended
Sensor Signal Conditioning and Threshold Detection
The PIC16C56-RCI/SO serves in simple sensor signal conditioning modules where a microcontroller reads an analog threshold through an external comparator and drives a digital output. With 25 bytes of RAM and 12 I/O pins, the device can interface to a handful of digital sensors and produce PWM or GPIO control signals. The industrial temperature rating supports factory-floor deployment, and the 3.3V/5V dual-voltage operation allows direct connection to common digital logic levels.
Recommended
Industrial Logic Replacement and Sequencers
The PIC16C56-RCI/SO replaces discrete 7400-series logic in industrial sequencer applications where flexibility and small board footprint matter. Engineers can implement a state machine, delay timer, or pulse generator in 1.5 KB of EPROM, eliminating dozens of discrete gates. The SOIC-18 package saves PCB area versus through-hole logic, while the RC oscillator tolerates noisy industrial supply environments better than crystal-based designs.
Recommended
Simple Embedded Logic Replacement (Glue Logic MCU)
The PIC16C56-RCI/SO serves as a glue-logic MCU in mixed-signal systems where programmable logic replaces multiple discrete AND, OR, and timer gates. With seven or eight hardware registers and a 2-level hardware stack, code-density advantages let engineers pack more functionality into 1.5 KB than competing 8-bit MCUs. The device operates from 3.3V or 5V, enabling direct interface to both 3.3V and 5V logic without level shifters.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C56-RCI/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C56-RC/P | PIC16C56-LPI/SO | PIC16C56-LPE/SO | PIC16C56-LP/SO | PIC16C56-HSI/SO |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | SOIC-18 (SO) | PDIP-18 (P) - through-hole variant | SOIC-18 (SO) - same | SOIC-18 (SO) - same | SOIC-18 (SO) - same | SOIC-18 (SO) - same |
| Program Memory | 1.5 KB EPROM | 1.5 KB EPROM | 1.5 KB EPROM | 1.5 KB EPROM | 1.5 KB EPROM | 1.5 KB EPROM |
| RAM | 25 bytes | 25 bytes | 25 bytes | 25 bytes | 25 bytes | 25 bytes |
| Oscillator Type | RC | RC | LP (low-power) | LP (low-power, extended temp) | LP (low-power, commercial temp) | HS (high-speed crystal) |
| I/O Pins | 12 | 12 | 12 | 12 | 12 | 12 |
| Operating Temperature | -40 C to +85 C (Industrial) | 0 C to +70 C (Commercial) or -40 C to +85 C (Industrial variant) | -40 C to +85 C (Industrial) | -40 C to +125 C (Extended) | 0 C to +70 C (Commercial) | -40 C to +85 C (Industrial) |
| Lifecycle Status | NRND | NRND | NRND | NRND | NRND | NRND |
| Supply Voltage | 3.3 V / 5 V | 3.3 V / 5 V | 2.5 V to 6.25 V (LP extended range) | 2.5 V to 6.25 V (LP extended range) | 2.5 V to 6.25 V (LP extended range) | 4.5 V to 5.5 V (HS higher minimum) |
Key Differentiators
- SOIC-18 industrial temperature RC variant (vs PIC16C56-RC/P)
- Industrial temperature with low-power oscillator option (vs PIC16C56-LP/SO)
- Highest-density EPROM in PIC16C5X sub-family (vs PIC16C55-RCI/SO)
Design Notes
Estimated: At VDD=5V, 12 I/O pins sourcing 10 mA each with 50% duty cycle, the PIC16C56-RCI/SO draws approximately 60 mA from the supply rail before adding core current. Decouple VDD with a 100 nF ceramic capacitor placed within 5 mm of pin 14, plus a 10 uF bulk capacitor on the same rail. The RC oscillator draws negligible power compared to I/O loading, so decoupling should target the I/O driver transients rather than the oscillator.
MCLR (pin 4) must be tied to VDD through a 10 kohm pull-up resistor for normal operation; leaving it floating causes intermittent resets or programming failures. The 2-level hardware stack limits nested subroutine calls to depth 2 - any third nested call will overwrite the return address and corrupt program flow. Engineers migrating from later PIC16 families must remember this constraint because PIC16F and PIC16F1XX parts offer 8-level or deeper stacks.
Route the RC oscillator network (pins 15 and 16) using short traces to a resistor-to-VDD and capacitor-to-VSS pair placed within 5 mm of the MCU. Keep digital switching traces away from the OSC1/OSC2 pins to prevent coupling noise into the oscillator, which can shift the instruction timing. The SOIC-18 footprint leaves minimal PCB area, so designers should use the smallest passive packages (0402 or 0603) to fit the BOM within the available board space.
The PIC16C56 family is designated 'Not Recommended for new designs' by Microchip, so production allocations may be limited. According to Microchip's NRND policy, the part is supported for existing customers but new design wins should use the flash-based PIC16F54 or PIC16F57 family. Designers specifying this part should plan a migration path or carry sufficient safety stock for the product lifecycle.
Compliance Information
RoHS compliance confirmed by icsuns.com product listing. No AEC-Q100 qualification claimed for this part; automotive applications should use AEC-Q100 qualified PIC16F alternatives.
