PIC16C56A-04/P - 8-Bit 4MHz OTP MCU 1.5KB | Microchip
MPN: PIC16C56A-04/P ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.95 | $2.95 |
| 10 | $2.66 | $26.60 |
| 100 | $2.3 | $230.00 |
| 500 | $2.05 | $1,025.00 |
| 1,000 | $1.85 | $1,850.00 |
PIC16C56A-04/P Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, program memory, data RAM, and peripheral I/O on one die. The PIC16C5X family belongs to the PIC (Peripheral Interface Controller) lineage and sits within the broader taxonomy: 8-bit MCU -> microcontroller -> embedded processor -> semiconductor. The "RISC" architecture of the PIC16C5X uses only 33 single-word, single-cycle instructions, simplifying code generation and enabling deterministic instruction timing — a hallmark of PIC mid-range and baseline cores.
Key differentiating specifications include: 33 single-word/single-cycle RISC instruction set, two-level deep hardware stack for subroutine nesting, one 8-bit real-time counter/timer (TMR0), Power-on Reset (POR), Watchdog Timer (WDT) with on-chip RC oscillator for reliable system recovery, and a wide 2.5 V to 6.25 V supply voltage range that allows battery and 5 V-rail designs. The OTP memory, four oscillator selections (RC, XT, HS, LP), and direct/indirect/relative addressing modes give designers flexibility in cost-optimized control loops.
Typical applications span automotive body controllers, appliance controls, security keypads, simple sensor interfaces, low-end consumer products, and replacement of discrete logic with programmable intelligence. Because the PIC16C56A-04/P is offered in commercial and automotive grades, it is also used in under-hood and dashboard subsystems where OTP and known-good silicon are preferred over flash.
A critical design consideration is that OTP parts cannot be reprogrammed in-circuit: firmware must be fully validated before programming. Engineers should plan for a programmer socket or a parallel-programmable strategy using the MPLAB PM3, and reserve the WDT for fail-safe recovery from code lockups.
This page synthesizes verified distributor pricing, same-family and cross-brand drop-in alternatives, and practical design notes that go beyond the manufacturer datasheet excerpt, helping procurement and embedded engineers evaluate the PIC16C56A-04/P against modern 8-bit replacements.
Drop-in alternatives for PIC16C56A-04/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 PIC16C56A-04/P (same form factor and footprint) — differing in Program Memory Size, Package, Timers, Watchdog Timer, Mounting Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C56A-04I/P
✅ Drop-In✓ In Stock
$2.3 / Unit
View Datasheet →PIC16C56A-20/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C56-04/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C55A-04/P
✅ Drop-In✓ In Stock
$2.18 / Unit
View Datasheet →PIC16C56A-04/P Maximum Ratings & Electrical Characteristics
| Manufacturer | Microchip Technology |
| Series | PIC 16C |
| Core Processor | PIC |
| Core Size | 8-Bit |
| Speed | 4 MHz |
| Program Memory Type | OTP (One-Time Programmable EPROM) |
| Program Memory Size | 1.5 KB (1K x 12) |
| RAM Size | 25 bytes |
| Number of I/O | 12 |
| Supply Voltage (Vcc) | 4.5 V to 5.5 V (extended 2.5 V to 6.25 V across family) |
| Number of Timers | 1 (TMR0, 8-bit) |
| Oscillator Type | External (RC / XT / HS / LP options) |
| Operating Temperature | 0C to +70C (commercial) |
| Package / Case | 18-PDIP (DIP-18, 2.54 mm pitch) |
| Mounting Type | Through-Hole |
| Instruction Set | 33 single-word/single-cycle instructions (RISC) |
| Stack Depth | 2 levels (hardware) |
| Watchdog Timer | Yes (with dedicated on-chip RC oscillator) |
| Power-on Reset | Yes |
| Connectivity | GPIO-only (no UART, SPI, I2C on this baseline device) |
PIC16C56A-04/P Pin Configuration
| Pin 1 | RA2 — Bidirectional I/O port A bit 2 |
| Pin 2 | RA3 — Bidirectional I/O port A bit 3 |
| Pin 3 | RC0 — Bidirectional I/O port C bit 0 |
| Pin 4 | /RESET — Active-low reset input |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0 — Bidirectional I/O port B bit 0 |
| Pin 7 | RB1 — Bidirectional I/O port B bit 1 |
| Pin 8 | RB2 — Bidirectional I/O port B bit 2 |
| Pin 9 | RB3 — Bidirectional I/O port B bit 3 |
| Pin 10 | RB4 — Bidirectional I/O port B bit 4 |
| Pin 11 | RB5 — Bidirectional I/O port B bit 5 |
| Pin 12 | RB6 — Bidirectional I/O port B bit 6 |
| Pin 13 | RB7 — Bidirectional I/O port B bit 7 |
| Pin 14 | VDD — Positive supply voltage |
| Pin 15 | OSC2 — Oscillator crystal/clock output |
| Pin 16 | OSC1 — Oscillator crystal/clock input |
| Pin 17 | RA0 — Bidirectional I/O port A bit 0 |
| Pin 18 | RA1 — Bidirectional I/O port A bit 1 |
Typical Applications
PIC16C56A-04/P is suitable for 6 applications: Automotive Body and Dashboard Controllers, Appliance Control Boards, Security Keypads and Access Control, Discrete Logic Replacement and Glue Logic, Sensor Interface and Signal Conditioning Nodes, Low-End Consumer Electronics and Toys.
Automotive Body and Dashboard Controllers
The PIC16C56A-04/P suits automotive body controllers, dashboard indicators, and simple sensor interface nodes where OTP memory provides code security and a 4 MHz clock is sufficient for polled I/O loops. Its 12 GPIO pins drive LEDs, read switches, and multiplex small displays without an external bus. The wide 2.5 V to 6.25 V supply tolerance handles 12 V automotive rails after regulation, and the Watchdog Timer provides fail-safe recovery from electrical transients. The 18-pin PDIP package suits hand-assembled prototypes and low-volume aftermarket modules where through-hole soldering is preferred over SMT. Automotive-grade PIC16C56A-04E variants extend the operating range to +125C for under-hood deployment.
Recommended
Appliance Control Boards
The PIC16C56A-04/P is widely deployed in white-goods appliance control boards such as washing-machine timers, microwave keypads, and dishwasher sensor interfaces. Its 33-instruction RISC core, 8-bit TMR0 counter, and GPIO-driven matrix scanning handle button debouncing, relay sequencing, and buzzer patterns without external peripherals. OTP memory locks the firmware so end customers cannot reflash or clone the controller, protecting OEM intellectual property. The Watchdog Timer recovers from motor noise and brown-out events common in appliance environments, and the 25-byte RAM supports modest state machines for cycle counters and mode flags. Commercial-grade temperature range fits indoor appliance enclosures.
Recommended
Security Keypads and Access Control
The PIC16C56A-04/P fits security keypads, RFID access readers, and simple alarm-panel nodes where OTP memory prevents code extraction and 4 MHz is adequate for debounced matrix scanning. Its 12 GPIO lines drive 4x4 key matrices directly, and the Watchdog Timer protects against lockup attempts that attempt to disable security response. The 25-byte RAM holds temporary PIN buffers and tamper flags, while the 1K x 12 program memory stores encryption routines and state-machine logic for entry sequencing. The baseline PIC16C5X core's deterministic single-cycle execution ensures predictable response times to keypad events. Industrial-temperature PIC16C56A-04I variants suit outdoor keypads.
Recommended
Discrete Logic Replacement and Glue Logic
The PIC16C56A-04/P replaces 74HC-series glue logic, decoder arrays, and small state machines with programmable intelligence that integrates multiple logic functions into a single chip. Its 12 GPIO pins replace 2-4 discrete logic ICs at lower board cost and BOM count. The RISC instruction set executes 4 MIPS at 4 MHz, sufficient to bit-bang custom protocols, drive 7-segment displays, or sequence relay matrices. The 1K x 12 OTP memory stores state-transition tables and timing constants that would otherwise require ROM-based logic. The 18-pin PDIP package is pin-compatible with standard DIP sockets used in legacy logic-replacement designs.
Recommended
Sensor Interface and Signal Conditioning Nodes
The PIC16C56A-04/P serves as a low-cost sensor interface node for thermistor bridges, simple analog front ends, and discrete-sensor multiplexer hubs in industrial and consumer systems. Its TMR0 counter measures pulse widths from flow meters, tachometers, and frequency-output sensors, while the GPIO lines drive multiplexer select lines and read comparator outputs. The 4 MHz clock provides 1 microsecond instruction timing, enabling polled scanning of up to 12 sensor channels without missing events. OTP memory locks calibration coefficients into the firmware for tamper-resistant field deployment. Industrial-temperature variants operate in factory-floor environments from -40C to +85C.
Recommended
Low-End Consumer Electronics and Toys
The PIC16C56A-04/P powers low-end consumer electronics and battery-operated toys where low unit cost, OTP code security, and minimal external components are decisive. The 25-byte RAM and 1K x 12 program memory store toy sound-effect sequences, LED chase patterns, and simple game logic without external memory. The 2.5 V to 6.25 V supply range supports 2xAA, 3xAA, or single 9 V battery packs directly. The Watchdog Timer prevents lockup when battery voltage sags, and the sleep-mode current in microamps extends battery life in idle states. The 18-pin PDIP package is well suited to through-hole toy and hobby-grade designs.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C56A-04/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C56A-04I/P | PIC16C56A-04/SO | PIC16C56A-20/P | PIC16C56-04/P | PIC16C55A-04/P |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 18-PDIP (through-hole) | 18-PDIP (through-hole) - same | 18-SOIC (surface mount) - different | 18-PDIP (through-hole) - same | 18-PDIP (through-hole) - same | 18-PDIP (through-hole) - same |
| Max Clock Speed | 4 MHz | 4 MHz | 4 MHz | 20 MHz | 4 MHz | 4 MHz |
| Program Memory | 1K x 12 OTP (1.5 KB) | 1K x 12 OTP (1.5 KB) | 1K x 12 OTP (1.5 KB) | 1K x 12 OTP (1.5 KB) | 1K x 12 OTP (1.5 KB) | 512 x 12 OTP (0.75 KB) |
| Data RAM | 25 bytes | 25 bytes | 25 bytes | 25 bytes | 25 bytes | 25 bytes |
| GPIO Count | 12 | 12 | 12 | 12 | 12 | 12 |
| Operating Temperature | 0C to +70C (commercial) | -40C to +85C (industrial) | 0C to +70C (commercial) | 0C to +70C (commercial) | 0C to +70C (commercial) | 0C to +70C (commercial) |
| Silicon Revision | A (second-generation, low power) | A (industrial temperature) | A | A (20 MHz speed grade) | Original (pre-A, higher power) | A (smaller memory variant) |
| Unit Price (qty 1) | $2.95 | $3.20 | $2.85 | $3.10 | $2.80 (legacy, may be NRND) | $2.65 |
Key Differentiators
- Industrial temperature option in same 18-pin PDIP footprint (vs PIC16C56A-04I/P)
- 20 MHz clock upgrade option in same package (vs PIC16C56A-20/P)
- Half-memory lower-cost alternative (vs PIC16C55A-04/P)
Design Notes
The PIC16C56A-04/P uses One-Time Programmable (OTP) memory, so firmware bugs cannot be corrected after programming - the chip must be discarded. Always program pre-production devices in low quantities and run full validation before committing to volume. For development cycles, use a windowed UV-erasable PIC16C56/JW or the flash-based PIC16F-series pin-compatible upgrade (e.g., PIC16F88) to iterate firmware before locking OTP production units.
Decouple VDD (pin 14) with a 100 nF ceramic capacitor placed within 5 mm of the supply pin, plus a 10 uF bulk capacitor on the board. The PIC16C56A-04/P is a baseline PIC16C5X device without internal brown-out reset (BOR), so supply droops below 4.0 V can cause code execution errors. Use an external MCP100 supervisor or design a power-on-reset network if the application operates near the VDD minimum.
Route the oscillator traces (OSC1 pin 16, OSC2 pin 15) as short as possible and keep them away from switching noise sources such as relay coils or PWM traces. For XT mode (4 MHz crystal), add a 22 pF load capacitor on each oscillator pin to ground. For RC mode, select a resistor value between 10 kohm and 100 kohm and a capacitor that yields the target frequency per the datasheet's RC oscillator graph. Place a ground guard ring around the oscillator pins if the board has noisy digital signals.
The 18-pin PDIP package requires a 2.54 mm pitch through-hole footprint with a standard DIP-18 socket recommended for development. Provide a 5 mm keep-out under the MCU for through-hole pin clearance on double-sided boards. If migrating to surface mount, the PIC16C56A-04/SO offers identical logic in 18-SOIC. Do not mix PIC16C5X baseline pinout with PIC16F-series mid-range pinouts - the GPIO port mapping differs and firmware must be rewritten.
Compliance Information
RoHS and REACH status not explicitly stated in verified data - marked unknown. Automotive grade PIC16C56A variants are available but not formally AEC-Q100 qualified per Microchip documentation.
