PIC16C56T-HSI/SS - 8-Bit 20MHz OTP MCU 1.5KB | Microchip
MPN: PIC16C56T-HSI/SS ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.85 | $3.85 |
| 10 | $3.47 | $34.70 |
| 100 | $3.08 | $308.00 |
| 500 | $2.72 | $1,360.00 |
| 1,000 | $2.41 | $2,410.00 |
PIC16C56T-HSI/SS Overview
An 8-bit OTP microcontroller is a single-chip computer with an 8-bit data path and program memory that can be written exactly once during production programming, balancing low unit cost against in-system reprogrammability. Within the broader product hierarchy, this places the PIC16C56 as a microcontroller -> embedded controller -> semiconductor device, ideal for high-volume, fixed-function appliances where firmware is finalized at build time. The PIC architecture uses a RISC instruction set with only 33 single-word instructions, reducing development complexity compared to CISC 8-bit alternatives.
Key features of the PIC16C56T-HSI/SS include a 12-bit instruction word, 8-bit data path, 12 I/O pins arranged as PORT A (RA0-RA3) and PORT B (RB0-RB7), an integrated Watchdog Timer (WDT) for reliable operation, and Power-On Reset (POR) for deterministic startup. The device supports an external high-speed oscillator and operates across a 2.5V to 6.0V supply range with low standby current typical of CMOS implementations.
The PIC16C56 employs a Harvard-style architecture with separate program and data buses, single-cycle instruction execution (except for program branches), and a two-level deep hardware stack. This results in deterministic timing suitable for interrupt-free control loops, an advantage over accumulator-based 8051-class parts in latency-sensitive tasks. The RISC core delivers roughly an order-of-magnitude performance advantage over competing 8-bit microcontrollers in the same price tier.
Typical applications include consumer appliance control (washing machines, microwave ovens, remote controls), automotive sub-system modules (seat controllers, simple sensor interfaces), industrial timer/counter modules, and battery-powered instrumentation. The PIC16C56 is well suited where code is frozen at production and unit cost dominates over in-field reprogrammability. For designs requiring re-programmability or larger memory, designers typically migrate to the PIC16F57 or PIC16F84A flash-based successors.
When designing with this device, note that the OTP memory cannot be erased, so firmware must be fully validated before production programming. Use Microchip's MPLAB PM3 Universal Device Programmer or equivalent gang programmer for high-volume assembly. For new designs, prefer the PIC16F-series flash-based equivalents unless the BOM cost advantage of OTP is decisive.
This page synthesizes distributor pricing, drop-in same-package alternatives drawn from the PIC16C5X family, and practical design notes not consolidated on any single distributor or manufacturer page.
Drop-in alternatives for PIC16C56T-HSI/SS — 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 PIC16C56T-HSI/SS (same form factor and footprint) — differing in Program Memory Size, Program Memory Type, I/O Pins, Package, Operating Temperature Range.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C54T-HSI/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C55T-HSI/SS
✅ Drop-In✓ In Stock
$2.05 / Unit
View Datasheet →PIC16C57T-HSI/SS
✅ Drop-In✓ In Stock
$4.55 / Unit
View Datasheet →PIC16C56T-10E/SS
✅ Drop-In✓ In Stock
$1.42 / Unit
View Datasheet →PIC16C56AT-04E/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C56T-HSE/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C56T-HSI/SS 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) |
| Data RAM | 25 bytes (25 x 8) |
| Maximum CPU Frequency | 20 MHz |
| Instruction Word Width | 12 bits |
| I/O Pins | 12 |
| Supply Voltage (Vdd) | 2.5 V to 6.0 V |
| Oscillator Mode | HS (High-Speed external) |
| Operating Temperature | -40 °C to +85 °C (Industrial) |
| Package | 20-SSOP (5.30 mm body width, 0.65 mm pitch) |
| Mounting Type | Surface Mount |
| Watchdog Timer (WDT) | Yes |
| Power-On Reset (POR) | Yes |
| Hardware Stack Depth | 2 levels |
PIC16C56T-HSI/SS Pin Configuration
| Pin 1 | RA2 — Bidirectional I/O port A bit 2 |
| Pin 2 | RA3 — Bidirectional I/O port A bit 3 |
| Pin 3 | RTCC — Real-Time Clock/Counter input (T0CKI) |
| Pin 4 | MCLR — Master Clear (reset) input, active low |
| 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 | VSS — Ground reference (second VSS pin) |
| Pin 15 | OSC2 — Oscillator output (crystal/resonator connection) |
| Pin 16 | OSC1 — Oscillator input (crystal/resonator connection) |
| Pin 17 | RA0 — Bidirectional I/O port A bit 0 |
| Pin 18 | RA1 — Bidirectional I/O port A bit 1 |
| Pin 19 | VSS — Ground reference (third VSS pin) |
| Pin 20 | VDD — Positive supply voltage (2.5V to 6.0V) |
Typical Applications
PIC16C56T-HSI/SS is suitable for 7 applications: Consumer Appliance Control, Automotive Sub-System Modules, Industrial Timer / Counter Modules, Battery-Powered Instrumentation, LED Display Drivers and Signage, Hobby and Educational Projects, Security Sensor Modules.
Consumer Appliance Control
The PIC16C56T-HSI/SS suits fixed-function consumer appliances such as microwave ovens, washing-machine control boards, and remote-control transmitters where firmware is frozen at production and BOM cost dominates. Its 1.5 KB OTP comfortably holds user-interface state machines, timer logic, and simple PID loops; 12 I/O pins drive 7-segment displays, keypads, and triac-based load switches. The 20 MHz CPU at 200 ns per instruction handles multiplexed display refresh and zero-crossing detection within tight 1-2 ms control windows. Compared with flash-based PIC16F84A successors, the OTP PIC16C56 saves $0.10-$0.30 per unit in million-unit appliance runs, which is decisive in commodity appliances.
Recommended
Automotive Sub-System Modules
Within automotive body-electronics modules (seat controllers, mirror positioners, simple sensor interfaces), the PIC16C56T-HSI/SS industrial-grade temperature rating and OTP one-time-programming fit well with high-volume fixed-function modules. The 12-bit instruction width and deterministic 200 ns instruction cycle at 20 MHz allow reliable motor-control PWM and switch-debounce handling without real-time OS overhead. Automotive designs requiring AEC-Q100 qualification should migrate to the PIC16F-series flash-based Q-graded parts (e.g., PIC16F1829-I/SS); the PIC16C56 OTP is not AEC-Q100 qualified and the industrial -40 to +85 °C range suffices only for cabin modules, not under-hood ECUs.
Recommended
Industrial Timer / Counter Modules
The PIC16C56T-HSI/SS serves as the controller for industrial timer relays, event counters, conveyor pulse-counting modules, and machine-cycle beacons. The integrated Watchdog Timer (WDT) automatically recovers the controller from software lockup caused by EMI in factory-floor environments. Power-On Reset (POR) ensures deterministic startup after power interruptions without external reset circuitry. The HS oscillator mode supports precise timing references up to 20 MHz; for sub-millisecond event counting the PIC16C56T-HSI/SS executes single-cycle increment instructions, making it cost-competitive against dedicated counter ICs in production volumes above 5k units per year.
Recommended
Battery-Powered Instrumentation
For battery-powered sensors and metering endpoints the PIC16C56T-HSI/SS offers low CMOS standby current typical of the PIC16C5X family, with the HS oscillator gated off during sleep for wake-on-timer operation. Operating across 2.5V to 6.0V Vdd, it runs directly from 2xAA, 3xAA, or single lithium-cell stacks. The 25-byte RAM accommodates small sensor-state buffers without dynamic-memory allocation overhead. For designs targeting sub-1 µA sleep current and active-mode currents in the hundreds-of-µA range, the PIC16C56 is competitive with newer low-power MCUs only when its sub-$3 unit cost is preserved across production volumes.
Recommended
LED Display Drivers and Signage
The PIC16C56T-HSI/SS is widely used as the controller in small LED-matrix signage, scoreboards, and animated decorative lighting fixtures where fixed patterns are pre-loaded into OTP at production. Its 12 I/O pins can drive a 4-digit 7-segment display via BCD-decoder/driver ICs, or matrix-multiplex up to 8x8 LED arrays with charlieplexing. At 20 MHz the CPU can refresh 64-LED matrices at >100 Hz, eliminating visible flicker. The 1.5 KB OTP holds bitmap fonts and animation sequences without external EEPROM; pair with constant-current LED drivers (e.g., TLC5940) for PWM dimming of larger arrays.
Recommended
Hobby and Educational Projects
The PIC16C56T-HSI/SS is a popular entry-level microcontroller in hobbyist and educational curricula because of its small 20-SSOP footprint, low cost, and the well-documented PIC16C5X instruction set taught in textbooks. Student projects using it include line-following robots, simple audio synthesizers, and DIY remote controls. However, the OTP requirement forces hobbyists to program each chip once, so educators often substitute the pin-compatible PIC16F84A or PIC16F57 (flash-based) for re-programmable prototyping; the PIC16C56 OTP remains the production part once firmware is finalized.
Recommended
Security Sensor Modules
In PIR motion-sensor modules, smoke-detector control boards, and door/window contact transmitters, the PIC16C56T-HSI/SS manages sensor signal-conditioning, debounce, and alarm-logic state machines within its 1.5 KB OTP. The Watchdog Timer guards against firmware hang-up from sensor-induced transients, and Power-On Reset ensures correct initialization after battery swaps. The industrial temperature range covers indoor security installations across most climates. For new designs requiring encryption or wireless interfaces, migrate to PIC16F or PIC18 families; the PIC16C56 OTP is appropriate only for low-cost standalone sensor modules where cost is the primary constraint.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C56T-HSI/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C54T-HSI/SS | PIC16C55T-HSI/SS | PIC16C57T-HSI/SS | PIC16C56T-10E/SS |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 20-SSOP | 20-SSOP (same) | 20-SSOP (same) | 20-SSOP (same) | 20-SSOP (same) |
| Program Memory | 1.5 KB (1K x 12) OTP | 512 x 12 OTP (-50%) | 512 x 12 OTP (-50%) | 2K x 12 OTP (+100%) | 1K x 12 OTP (same) |
| Maximum CPU Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 10 MHz (-50%) |
| Data RAM | 25 bytes | 25 bytes | 25 bytes | 72 bytes (+188%) | 25 bytes |
| I/O Pins | 12 | 12 | 20 (+67%) | 20 (+67%) | 12 |
| Oscillator Mode | HS (High-Speed) | HS | HS | HS | HS |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete |
Key Differentiators
- Industry-standard PIC16C5X family pin-compatible for drop-in upgrade/downgrade (vs PIC16C54T-HSI/SS)
- Larger code memory than PIC16C55 in same package (vs PIC16C55T-HSI/SS)
- 20 MHz maximum CPU clock at industrial temperature (vs PIC16C56T-10E/SS)
Design Notes
OTP memory cannot be erased - any firmware bug shipped to the PIC16C56T-HSI/SS becomes a permanent hardware defect requiring scrap and re-programming. Establish a firmware validation gate using a flash-based PIC16F-series development board (e.g., PIC16F84A-I/P) and lock down the production firmware image only after full EMC, timing, and unit-acceptance testing. Allocate at least 15-20% code-margin in the 1.5 KB OTP for last-minute bug fixes, otherwise migrate to PIC16C57T-HSI/SS (2K x 12) which shares the same SSOP-20 footprint.
The PIC16C56T-HSI/SS specifies 2.5V to 6.0V Vdd; below 4.5V the HS oscillator accuracy degrades and the brown-out detection (if enabled via configuration) may trigger unexpectedly. For designs powered by 3xAA alkaline cells, add a bulk decoupling capacitor of 10 µF tantalum or ceramic plus a 100 nF decoupling cap within 5 mm of VDD pin 20. Estimate: HS-mode operating current at 20 MHz and 5V is typically 2-5 mA, so a 3xAA pack (4.5V nominal, 3.3V end-of-life) has limited run-time at full clock - consider the LP or RC oscillator variants for battery designs.
Place the HS-mode crystal or ceramic resonator within 5 mm of OSC1 (pin 16) and OSC2 (pin 15), and route the oscillator traces over a continuous ground plane to minimize EMI pickup. Keep high-current switching traces (relay drivers, triac snubbers) at least 5 mm away from the oscillator traces to prevent clock distortion. The SSOP-20 exposed-pad is not present on this package - thermal dissipation is via the 20 gull-wing leads, which is adequate for the sub-50 mA operating current of this CMOS-OTP MCU.
Compliance Information
Compliance status not stated in retrieved distributor snippets as of 2026-09-17. The PIC16C5X family predates many RoHS declarations; verify against the lot certificate of conformance or contact Microchip for an authoritative declaration. Device is not AEC-Q100 qualified (industrial grade only, -40 to +85 °C).
