PIC16C56-HSI/P - 8-Bit 20MHz 1.5KB OTP MCU 18-PDIP | Microchip
MPN: PIC16C56-HSI/P ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.63 | $2.63 |
| 10 | $2.39 | $23.90 |
| 100 | $2.1 | $210.00 |
| 500 | $1.85 | $925.00 |
| 1,000 | $1.62 | $1,620.00 |
PIC16C56-HSI/P Overview
A microcontroller (MCU) is a single-chip computer containing a CPU core, program memory, data memory, and programmable I/O peripherals, designed for embedded control tasks. The PIC16C5x family uses a Harvard architecture with a 12-bit wide instruction word and 8-bit wide data path, providing roughly 2:1 code compression over competitive 8-bit MCUs of the same era. The PIC16C56-HSI/P fits within the broader taxonomy: microcontroller -> embedded controller -> semiconductor IC, and is designed for cost-sensitive and space-constrained embedded applications.
Key features include a two-level deep hardware stack, direct/indirect/relative addressing modes, an 8-bit real-time clock/counter (TMR0) with 8-bit prescaler, and 12 digital I/O pins. The OTP program memory allows one-time field programming via Microchip device programmers such as MPLAB PM3, while the simple 33-instruction set reduces firmware development time. Seven or eight special-function hardware registers provide register-based peripheral control.
Architecturally, the PIC16C56 separates code and data buses (Harvard architecture) which lets the CPU fetch an instruction and read data in the same cycle, doubling throughput versus single-bus designs. The 12-bit instruction word is highly orthogonal and symmetrical, simplifying assembler programming. The HS oscillator supports external crystal or resonator operation from approximately 4 MHz to 20 MHz, while the 8-bit timer/counter and prescaler handle periodic interrupt generation and event counting.
Typical applications include consumer appliance control, low-end automotive subsystems (body controllers, lighting), industrial automation timers/counters, simple sensor front-ends, LED sequencing, and replacement of discrete logic in legacy designs. The 18-pin PDIP package supports prototyping and through-hole assembly favored in educational, hobbyist, and legacy maintenance environments.
When designing with this part, note that OTP memory cannot be erased - firmware must be fully validated before programming. For new designs, consider PIC16F equivalents with Flash memory for in-circuit reprogrammability. The HS oscillator requires an external crystal or resonator across OSC1/OSC2 with appropriate loading capacitors.
This page synthesizes distributor pricing, drop-in same-package alternatives within the PIC16C5x family, and design considerations not consolidated in the manufacturer datasheet, helping engineers select a pin-compatible replacement or source this legacy part efficiently.
Drop-in alternatives for PIC16C56-HSI/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 PIC16C56-HSI/P (same form factor and footprint) — differing in Package, Program Memory Size, Program Memory Type, Timers, Core Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C55-HSI/P
✅ Drop-In✓ In Stock
$2.6 / Unit
View Datasheet →PIC16C56-HSE/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C56-HS/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C56-LP/P
✅ Drop-In✓ In Stock
$3.39 / Unit
View Datasheet →PIC16C56-RC/P
✅ Drop-In✓ In Stock
$4.65 / Unit
View Datasheet →PIC16C57-HSI/P
✅ Drop-In✓ In Stock
$1.89 / Unit
View Datasheet →PIC16C56-HSI/P Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC, Harvard |
| Instruction Set Width | 12-bit |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 1.5 KB (1K x 12) |
| RAM | 25 bytes |
| Maximum Clock Frequency | 20 MHz |
| Operating Voltage | 4.5 V to 5.5 V |
| I/O Pins | 12 |
| Timers | 1 x 8-bit (TMR0) with 8-bit prescaler |
| Hardware Stack | 2-level |
| Oscillator Type | HS (High-Speed external crystal/resonator) |
| Temperature Grade | Industrial (-40C to +85C) |
| Package | 18-pin PDIP (0.300", 7.62 mm) |
| Mounting Type | Through-Hole |
| RoHS Status | Compliant (lead-free) |
PIC16C56-HSI/P Pin Configuration
| Pin 1 | RA2 — Port A bit 2 (bidirectional I/O) |
| Pin 2 | RA3 — Port A bit 3 (bidirectional I/O) |
| Pin 3 | RA4/T0CKI — Port A bit 4 / Timer0 clock input |
| Pin 4 | MCLR/VPP — Master Clear reset (active low) / Programming voltage |
| Pin 5 | VSS — Ground |
| 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 (4.5 V to 5.5 V) |
| Pin 15 | OSC1 — Crystal/Resonator input (HS mode) |
| Pin 16 | OSC2 — Crystal/Resonator output (HS mode) |
| Pin 17 | RA0 — Port A bit 0 (bidirectional I/O) |
| Pin 18 | RA1 — Port A bit 1 (bidirectional I/O) |
Typical Applications
PIC16C56-HSI/P is suitable for 6 applications: Consumer Appliance Control, LED Sequencing and Lighting Controllers, Industrial Timer and Counter Modules, Automotive Body Electronics (Legacy), Replacement of Discrete Logic (Glue Logic Consolidation), Educational and Hobbyist Prototyping.
Consumer Appliance Control
The PIC16C56-HSI/P fits consumer appliance controllers (washing machines, microwave ovens, coffee makers, dishers) because its 1.5 KB OTP, 25-byte RAM, and 12 I/O pins handle switch scanning, relay drive, and timing functions at minimal cost. The 20 MHz HS oscillator provides responsive control-loop timing for motor speed, heater PWM via software, and user-interface debounce. Industrial temp grade supports kitchen/laundry environments. The 18-pin PDIP simplifies hand-assembly for low-volume white goods and field-serviceable legacy units.
Recommended
LED Sequencing and Lighting Controllers
The PIC16C56-HSI/P drives LED sequencing, marquee, and decorative lighting controllers using its 12 I/O pins to multiplex up to 12 LEDs directly (or drive larger arrays via external drivers). The 8-bit TMR0 with prescaler generates precise timing for chase patterns, PWM dimming via software, and color-mixing RGB sequences. At 20 MHz the instruction cycle is 200 ns, providing smooth transitions at refresh rates exceeding 100 Hz. The HS oscillator and 5V supply directly drive LED arrays without level shifters.
Recommended
Industrial Timer and Counter Modules
The PIC16C56-HSI/P serves as the core of industrial timer/counter modules, conveyor controllers, and process-interval timers where its 8-bit TMR0 with 8-bit prescaler supports up to 256-step timing resolution at high frequencies. Industrial temperature grade (-40C to +85C) ensures operation in factory environments. The 20 MHz HS oscillator drives precise event counting and time-delay generation, while 12 I/O pins interface with relays, optocouplers, and 7-segment displays. OTP memory locks production firmware against field tampering.
Recommended
Automotive Body Electronics (Legacy)
The PIC16C56-HSI/P powers legacy automotive body controllers (interior lighting, seat-position memories, mirror adjusters, simple alarm systems) where its 12 I/O pins drive relay and LED loads, and its 20 MHz HS oscillator handles multiplexed switch scanning at high speed. Industrial temp grade supports under-dash environments. OTP memory secures the production firmware against unauthorized modification. For new automotive designs, AEC-Q100 qualified PIC16F or dsPIC variants are mandatory; the PIC16C56 remains a maintenance part for installed vehicles.
Recommended
Replacement of Discrete Logic (Glue Logic Consolidation)
The PIC16C56-HSI/P replaces 74-series TTL/CMOS glue logic in legacy board designs where its 12 I/O pins and software-driven state machine eliminate multiple 74HC gates, timers, and counters. The 33-instruction RISC set supports state-table encoding and lookup tables in 1.5 KB OTP, while 25 bytes RAM handles debounced inputs and latched outputs. This consolidation reduces PCB area, lowers BOM cost, and enables design changes via firmware rather than board respins. Industrial temp grade supports telecom, instrumentation, and factory floor retrofits.
Recommended
Educational and Hobbyist Prototyping
The PIC16C56-HSI/P is widely used in university microcontroller courses, hobbyist projects, and DIY electronics because the 18-pin PDIP is breadboard-friendly and through-hole solderable, the 33-instruction PIC16C5X ISA is the simplest PIC family to learn, and the 20 MHz HS oscillator allows demonstration of timing-critical concepts (PWM, frequency generation, serial bit-banging). The legacy status means used development boards (PICSTART Plus, MPLAB PM3) are abundant. Industrial temp grade ensures student projects work in non-climate-controlled environments.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C56-HSI/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C55-HSI/P | PIC16C56-HSE/P | PIC16C56-HS/P | PIC16C56-LP/P | PIC16C56-RC/P |
|---|---|---|---|---|---|---|
| Package | 18-PDIP (0.300") | 18-PDIP (0.300") - same | 18-PDIP (0.300") - same | 18-PDIP (0.300") - same | 18-PDIP (0.300") - same | 18-PDIP (0.300") - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| OTP Program Memory | 1.5 KB (1K x 12) | 512 x 12 (smaller) | 1K x 12 (same) | 1K x 12 (same) | 1K x 12 (same) | 1K x 12 (same) |
| RAM | 25 bytes | 24 bytes | 25 bytes (same) | 25 bytes (same) | 25 bytes (same) | 25 bytes (same) |
| Max Clock Frequency | 20 MHz | 20 MHz (same) | 20 MHz (same) | 20 MHz (same) | ~200 kHz (lower) | ~4 MHz (lower) |
| Oscillator Type | HS (High-Speed crystal/resonator) | HS (same) | HS (same) | HS (same) | LP (Low-Power crystal) | RC (resistor/capacitor) |
| Temperature Grade | Industrial (-40C to +85C) | Industrial (same) | Extended | Standard (0C to +70C) | Industrial (same) | Industrial (same) |
| I/O Pins | 12 | 12 (same) | 12 (same) | 12 (same) | 12 (same) | 12 (same) |
| Operating Voltage | 4.5 V to 5.5 V | 4.5 V to 5.5 V (same) | 4.5 V to 5.5 V (same) | 4.5 V to 5.5 V (same) | 2.5 V to 6.25 V (wider) | 3.0 V to 6.25 V (wider) |
| Lifecycle Status | Active (legacy) | Active (legacy) | Active (legacy) | Active (legacy) | Active (legacy) | Active (legacy) |
Key Differentiators
- Identical 1K x 12 OTP memory and 25-byte RAM with industrial temp grade (vs PIC16C55-HSI/P)
- Industrial temperature grade (-40C to +85C) versus standard 0C to +70C (vs PIC16C56-HS/P)
- HS high-speed crystal oscillator supports 4-20 MHz operation (vs PIC16C56-LP/P)
- Crystal-accurate HS timing versus RC-network timing tolerance (vs PIC16C56-RC/P)
Design Notes
PIC16C56-HSI/P operates from 4.5 V to 5.5 V. Add a 100 nF decoupling capacitor as close as possible to VDD (pin 14) and VSS (pin 5), plus a 10 uF bulk capacitor on the supply rail. The HS oscillator draws additional current during crystal startup - allow 10-50 ms for the crystal to stabilize after power-up before asserting code execution timing. MCLR (pin 4) must be tied to VDD through a 10 kohm pull-up resistor for normal operation; during programming, MCLR receives VPP (typically 13-14 V).
OTP (One-Time-Programmable) memory cannot be erased - any firmware bug that gets programmed into the device is permanent for that IC. Always validate firmware in a Flash-based equivalent (PIC16F84A, PIC16F630) or in MPLAB SIM before committing to OTP production programming. Also note that PIC16C5X has only a 2-level hardware stack - deeply nested subroutines will overwrite the return address, causing erratic behavior. Use assembly-language programming discipline and avoid deep call chains.
Keep the HS crystal (typically 4-20 MHz) and its loading capacitors physically close to OSC1 (pin 15) and OSC2 (pin 16). Place the crystal case ground tab to a ground plane via short trace. Avoid routing digital switching signals (relay coils, motor drives, PWM outputs) parallel to the crystal traces - this injects noise and can cause oscillator instability or frequency shift. For long MCLR trace length, add a 100 nF capacitor from MCLR to VSS to filter reset noise.
Compliance Information
RoHS compliant lead-free per LCSC and Heisener listings as of 2026-09-16. Not AEC-Q100 qualified - this is a legacy industrial-grade part; for new automotive designs, use PIC16F or dsPIC variants with AEC-Q100 qualification. Halogen-free status not explicitly stated in available data.
