PIC16C56A-04I/P - 8-Bit 4MHz OTP MCU, 1.5KB | Microchip
MPN: PIC16C56A-04I/P ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.6 | $3.60 |
| 10 | $3.24 | $32.40 |
| 100 | $2.88 | $288.00 |
| 500 | $2.59 | $1,295.00 |
| 1,000 | $2.3 | $2,300.00 |
PIC16C56A-04I/P Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU, RAM, non-volatile program memory, and peripherals. The PIC16C5X family implements a RISC architecture with only 33 single-word/single-cycle instructions, delivering 2:1 code compression versus other 8-bit MCUs in its class, and belongs to the broader hierarchy: 8-bit MCU -> microcontroller -> embedded controller -> semiconductor. The 'C' in PIC16C56A designates the EPROM/OTP program-memory variant, while the '04' suffix denotes a 4 MHz maximum clock and the 'I' suffix indicates the industrial temperature range (-40C to +85C).
Key features of the PIC16C56A-04I/P include 12 I/O pins, an 8-bit real-time clock/counter (TMR0) with a programmable prescaler, a two-level deep hardware stack, direct/indirect/relative addressing modes, a watchdog timer, and a power-on reset circuit. The device supports 2.5V to 6.25V operating voltage (industrial), is fully static for low-power operation, and offers seven or eight special-function hardware registers.
The PIC16C56A uses a 12-bit instruction word with an 8-bit data path, executed in a single instruction cycle (4 clock cycles). The RISC design reduces instruction count, which in turn reduces code size and improves deterministic execution - ideal for tight embedded loops and interrupt-driven designs. With 1K instructions of OTP program memory, parts are programmed once and cannot be electrically erased; this suits mature, fixed-function designs.
Typical applications include appliance control, security panels, simple sensor interfaces, hobby projects, educational platforms, and industrial timer/counter modules. The 18-pin PDIP package is breadboard-friendly, making it a long-standing favorite for learning and prototyping.
When designing with the PIC16C56A-04I/P, consider that OTP memory cannot be reprogrammed - this part suits production-ready firmware only, not iterative development. For development, use the PIC16F56 (Flash) or PIC16C56A JW (windowed) variants in the same family.
Drop-in alternatives for PIC16C56A-04I/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-04I/P (same form factor and footprint) — differing in Program Memory Size, Program Memory Type, RAM Size, Timers, Core.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C56A-04E/P
✅ Drop-In✓ In Stock
$1.21 / Unit
View Datasheet →PIC16C55A-04I/P
✅ Drop-In✓ In Stock
$1.52 / Unit
View Datasheet →PIC16C54A-04I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C57C-04I/P
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.05 / Unit
View Datasheet →PIC16F57-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C56A-04I/P Maximum Ratings & Electrical Characteristics
| Core | PIC 8-bit RISC |
| Program Memory Size | 1.5 KB (1K x 12) OTP |
| RAM Size | 25 bytes |
| Maximum Clock Frequency | 4 MHz |
| Instruction Word Width | 12 bits |
| Data Path Width | 8 bits |
| Number of I/O Pins | 12 |
| I/O Voltage Range | 2.5 V to 6.25 V |
| Operating Temperature Range | -40 C to +85 C (Industrial) |
| Package | 18-pin PDIP (P) |
| Mounting Type | Through-Hole |
| Timers | 1 x 8-bit (TMR0) with prescaler |
| Stack Depth | 2 levels (hardware) |
| Watchdog Timer | Yes |
| Power-On Reset | Yes |
| Architecture | RISC, 33 instructions, single-cycle |
| Program Memory Type | OTP (One-Time Programmable) |
| RoHS Status | Compliant |
| Lead-Free | Yes |
PIC16C56A-04I/P Pin Configuration
| Pin 1 | RA2 — Bidirectional I/O pin / Port A bit 2 |
| Pin 2 | RA3 — Bidirectional I/O pin / Port A bit 3 |
| Pin 3 | RA0/T0CKI — Bidirectional I/O pin / Timer0 clock input |
| Pin 4 | RA1 — Bidirectional I/O pin / Port A bit 1 |
| Pin 5 | MCLR — Master Clear (Reset) input, active low |
| Pin 6 | VSS — Ground reference |
| Pin 7 | OSC1/CLKIN — Oscillator crystal input / external clock input |
| Pin 8 | OSC2/CLKOUT — Oscillator crystal output / clock output (Fosc/4) |
| Pin 9 | RB0/INT — Bidirectional I/O pin / external interrupt input |
| Pin 10 | RB1 — Bidirectional I/O pin / Port B bit 1 |
| Pin 11 | RB2 — Bidirectional I/O pin / Port B bit 2 |
| Pin 12 | RB3 — Bidirectional I/O pin / Port B bit 3 |
| Pin 13 | RB4 — Bidirectional I/O pin / Port B bit 4 |
| Pin 14 | RB5 — Bidirectional I/O pin / Port B bit 5 |
| Pin 15 | RB6 — Bidirectional I/O pin / Port B bit 6 |
| Pin 16 | RB7 — Bidirectional I/O pin / Port B bit 7 |
| Pin 17 | VDD — Positive supply voltage |
| Pin 18 | NC — Not connected (per datasheet) |
Typical Applications
PIC16C56A-04I/P is suitable for 6 applications: Appliance Control, Security Alarm Panels, Industrial Timer / Counter Modules, Educational / Hobby Electronics, Simple Sensor Interfaces, Automotive Body Modules (legacy).
Appliance Control
The PIC16C56A-04I/P's 1.5 KB OTP program memory and 12 digital I/O pins are well matched to fixed-function appliance controllers such as washing machine timers, microwave keypads, and toaster oven controllers. The RISC 33-instruction set delivers deterministic 1 microsecond instruction execution at 4 MHz, ideal for real-time motor control loops. The industrial -40C to +85C temperature range tolerates the heat of consumer enclosures, and the watchdog timer provides the failsafe behavior required by IEC 60335 household appliance safety standards. Unlike Flash MCUs, OTP delivers zero firmware-erosion risk across decades of operation in always-on appliances.
Recommended
Security Alarm Panels
The PIC16C56A-04I/P fits wired intrusion alarm panels where its 12 I/O pins read multiple zone loops and drive piezo sirens, relay outputs, and keypad scanning logic. The 1.5 KB OTP holds the entire detection and reporting state machine, while 25 bytes of RAM is sufficient for zone-status flags and entry-delay counters. The hardware watchdog prevents lockup in unattended installations, and the 2.5V-6.25V supply range operates directly from a 5V or 6V backup-battery rail. Because the firmware is OTP, field tampering to alter alarm logic is impossible - an important security property for commercial intrusion systems.
Recommended
Industrial Timer / Counter Modules
The PIC16C56A-04I/P's 8-bit TMR0 counter with programmable prescaler makes it a natural fit for industrial timer and event-counter modules such as conveyor-belt cycle counters, machine-hour meters, and conveyor-stop debouncers. The 2-level hardware stack and 33 single-cycle instructions allow tight polling loops with predictable timing - important for IEC 61131 industrial-control signal chains. The industrial temperature rating handles factory-floor environments, and OTP ensures decades of stable operation without firmware corruption from battery-backed power events common in motor-drive cabinets.
Recommended
Educational / Hobby Electronics
The PIC16C56A-04I/P's 18-pin PDIP through-hole package is breadboard-friendly, making it a popular teaching example for RISC architecture and embedded-C courses. At 4 MHz, students can observe instruction execution on a scope and learn the 33-instruction PIC16C5X instruction set without the complexity of modern peripherals. The hardware stack and direct/indirect/relative addressing modes illustrate fundamental MCU concepts clearly. For iterative student projects, the PIC16F56 (Flash) is pin-compatible; for advanced labs that need erasing, the PIC16C56A/JW windowed variant allows UV erasure of OTP.
Recommended
Simple Sensor Interfaces
The PIC16C56A-04I/P can be used as a low-cost preprocessor for sensor arrays - reading analog sensors via RC-time conversion on an I/O pin and producing a serial bitstream or PWM output to a host system. With 12 I/O pins, it can interface 4-6 sensors and still have spare pins for status LEDs. The fully static CMOS design draws microamps in sleep modes, making it a practical choice for battery-powered remote sensor modules with multi-year battery life. OTP memory prevents firmware drift and accidental reprogramming in field-deployed sensor nodes.
Recommended
Automotive Body Modules (legacy)
Although automotive designs have moved to CAN-bus MCUs, the PIC16C56A-04I/P still serves in legacy automotive body modules for low-end vehicles, controlling simple functions like interior lighting timers, seat-bear reminder chimes, and accessory delay-off relays. The industrial temperature range handles cabin environments, and the 4 MHz clock is sufficient for slow body-control loops. OTP ensures firmware integrity over 10+ year vehicle service life, and the small PDIP footprint drops easily onto existing service-replacement PCBs that have been in production since the 1990s.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C56A-04I/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C56A-04E/P | PIC16C55A-04I/P | PIC16C54A-04I/P | PIC16F57-I/P |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 18-pin PDIP (P) | 18-pin PDIP - same | 18-pin PDIP - same | 18-pin PDIP - same | 18-pin PDIP - same |
| Program Memory | 1.5 KB OTP (1K x 12) | 1.5 KB OTP - same | 768 B OTP | 512 B OTP | 3 KB Flash |
| Memory Type | OTP (One-Time Programmable) | OTP - same | OTP - same | OTP - same | Flash (reprogrammable) |
| RAM Size | 25 bytes | 25 bytes - same | 24 bytes | 25 bytes - same | 25 bytes - same |
| Maximum Clock Frequency | 4 MHz | 4 MHz - same | 4 MHz - same | 4 MHz - same | 4 MHz - same |
| Number of I/O Pins | 12 | 12 - same | 12 - same | 12 - same | 12 - same |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +125C (Extended) | -40C to +85C - same | -40C to +85C - same | -40C to +85C - same |
| Architecture | 8-bit RISC, 33 instructions | 8-bit RISC - same | 8-bit RISC - same | 8-bit RISC - same | 8-bit RISC - same |
Key Differentiators
- Cost-optimized OTP memory for high-volume production (vs PIC16F57-I/P)
- Maximum program memory within the PIC16C5X 18-pin family (vs PIC16C55A-04I/P)
- Industrial temperature range standard vs extended upgrade path (vs PIC16C56A-04E/P)
- Mature, multi-source stable supply chain (vs Newer PIC16F1xxx family)
Design Notes
OTP memory cannot be electrically reprogrammed - if firmware is buggy, the part must be physically replaced. Budget for scrap during early production ramp and consider the PIC16F57-I/P (Flash, same pinout) for development builds. Once firmware is frozen, transition to PIC16C56A-04I/P for cost-optimized production.
The PIC16C56A-04I/P draws only microamps in sleep mode thanks to its fully static CMOS design. To enter sleep, execute the SLEEP instruction; wake on MCLR reset, watchdog timeout, or external interrupt on RB0/INT. Place a 0.1uF decoupling capacitor within 5mm of VDD pin 17 and a bulk capacitor (4.7uF or larger) on the supply rail to prevent brown-out on sleep-wake transitions.
The 18-pin PDIP package leaves pins 18 as NC (not connected) - do not route signals to this pin. Place the oscillator crystal (or ceramic resonator) within 5mm of OSC1 (pin 7) and OSC2 (pin 8), with the load capacitors grounded to VSS. Long oscillator traces cause noise injection and timing drift. The MCLR pin (pin 5) typically requires a 10k pull-up to VDD; for production designs, add a 100nF cap and diode clamp for ESD protection.
The PIC16C56A-04I/P has no internal pull-ups on PORTB - external 10k-47k pull-ups are required on RB0-RB7 for reliable input reading. The T0CKI pin (pin 3) shares RA0; if T0CKI is used as the timer clock source, configure RA0 as input in the TRIS register. The MCLR pin is internally filtered but should remain isolated from noisy switching signals to avoid spurious resets.
Compliance Information
RoHS compliant per Microchip product page. Not AEC-Q100 qualified - automotive applications should use PIC16C56A-04E variants or newer automotive-grade PIC16F families.