PIC16C56A/JW - 8-Bit 20MHz 1.5KB EPROM MCU | Microchip
MPN: PIC16C56A/JW ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.85 | $9.85 |
| 10 | $8.95 | $89.50 |
| 100 | $7.85 | $785.00 |
| 500 | $6.95 | $3,475.00 |
| 1,000 | $5.95 | $5,950.00 |
PIC16C56A/JW Overview
A PIC microcontroller (Programmable Intelligent Computer, also known as Peripheral Interface Controller) is a Harvard-architecture RISC MCU family in which program and data memories occupy separate address spaces. The PIC16C5x sub-family is the legacy "baseline" tier of PIC microcontrollers, positioned below the PIC16C7x/8x mid-range family and well below the PIC18 enhanced family in the modern Microchip taxonomy. The 'C' suffix denotes CMOS EPROM technology (later replaced by flash-based PIC16F parts), and the JW package is reserved almost exclusively for engineering development because of its quartz window and high cost.
Key features of the PIC16C56A include seven or eight special-function hardware registers, a two-level deep hardware call stack, direct/indirect/relative addressing modes, an 8-bit real-time clock/counter (TMR0) with a programmable prescaler, 12 programmable digital I/O lines, a Power-on Reset (POR) block, and a Watchdog Timer (WDT) for unattended operation. The Harvard architecture separates the 12-bit program bus from the 8-bit data bus, allowing instruction fetch and operand access to occur in the same cycle.
Typical applications include low-cost 8-bit embedded control in industrial timers and counters, appliance controllers, simple sensor front-ends, LED and relay driver boards, and educational/hobbyist platforms where the UV-erasable window allows repeated firmware iteration. The JW windowed CERDIP package is rarely used in production builds because the OTPEPROM can be erased and reprogrammed in-circuit by exposing the die to UV light through the quartz window.
Designers should note that the PIC16C56A is widely regarded as mature/legacy silicon. For new designs, Microchip recommends the flash-based PIC16F54 in a modern SOIC or QFN package. The CERDIP JW variant is best reserved for development, lab work, and legacy board repair. Pricing varies significantly with availability because of limited production runs.
Drop-in alternatives for PIC16C56A/JW — 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/JW (same form factor and footprint) — differing in Program Memory Size, Core Architecture, Program Memory Type, I/O Pins, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C56/JW
✅ Drop-In✓ In Stock
$7.4 / Unit
View Datasheet →PIC16C55/JW
✅ Drop-In✓ In Stock
$10.4 / Unit
View Datasheet →PIC16C554/JW
✅ Drop-In✓ In Stock
$4.69 / Unit
View Datasheet →PIC16C558/JW
✅ Drop-In✓ In Stock
$4.85 / Unit
View Datasheet →PIC16C54/JW
✅ Drop-In✓ In Stock
$4.85 / Unit
View Datasheet →PIC16C56A/JW Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC (Harvard) |
| Program Memory Size | 1.5 KB (1K x 12) EPROM, UV-erasable |
| Data RAM | 25 bytes |
| Data EEPROM | None |
| Instruction Width | 12-bit |
| Data Bus Width | 8-bit |
| Maximum Clock Frequency | 20 MHz |
| Operating Voltage Range | 2.5 V to 6.25 V (commercial) |
| Programmable I/O Pins | 12 |
| Timers | 1 x 8-bit TMR0 with prescaler |
| Hardware Stack Depth | 2 levels |
| Watchdog Timer (WDT) | Yes |
| Power-on Reset (POR) | Yes |
| Package | 18-pin CERDIP with UV window (JW) |
| Mounting Type | Through-Hole |
| Operating Temperature | 0C to +70C (commercial) |
PIC16C56A/JW Pin Configuration
| Pin 1 | RA2 — Port A bit 2 (bidirectional digital I/O) |
| Pin 2 | RA3 — Port A bit 3 (bidirectional digital I/O) |
| Pin 3 | RTCC — TMR0 real-time clock/counter external input |
| Pin 4 | MCLR — Master Clear (reset, active low) |
| Pin 5 | VSS — Ground |
| Pin 6 | RB0 — Port B bit 0 (bidirectional digital I/O) |
| Pin 7 | RB1 — Port B bit 1 (bidirectional digital I/O) |
| Pin 8 | RB2 — Port B bit 2 (bidirectional digital I/O) |
| Pin 9 | RB3 — Port B bit 3 (bidirectional digital I/O) |
| Pin 10 | RB4 — Port B bit 4 (bidirectional digital I/O) |
| Pin 11 | RB5 — Port B bit 5 (bidirectional digital I/O) |
| Pin 12 | RB6 — Port B bit 6 (bidirectional digital I/O) |
| Pin 13 | RB7 — Port B bit 7 (bidirectional digital I/O) |
| Pin 14 | VDD — Positive supply voltage |
| Pin 15 | OSC1/CLKIN — Oscillator input / external clock in |
| Pin 16 | OSC2/CLKOUT — Oscillator output / crystal connection |
| Pin 17 | RA0 — Port A bit 0 (bidirectional digital I/O) |
| Pin 18 | RA1 — Port A bit 1 (bidirectional digital I/O) |
Typical Applications
PIC16C56A/JW is suitable for 6 applications: Industrial Timer and Counter Controller, Appliance Control Board, Educational Microcontroller Training Kit, Sensor Front-End and Signal Conditioning, LED Driver and Display Sequencer, Legacy Board Repair and Obsolete Inventory Sustainment.
Industrial Timer and Counter Controller
The PIC16C56A/JW's 8-bit TMR0 with programmable prescaler makes it a natural fit for industrial timer and pulse-counter boards. Its 1.5 KB EPROM holds compact state-machine code for sequencing relays, while the 12 digital I/O lines drive seven-segment displays, keypad scans, and buzzer outputs directly. At 20 MHz the instruction cycle is 200 ns, which is fast enough to debounce mechanical contacts in firmware and count quadrature encoder pulses in real time. The Watchdog Timer recovers the MCU from firmware lockups in unattended factory installations, and Power-on Reset guarantees a defined startup after brown-out events on noisy 24V industrial rails. The CERDIP JW windowed package is ideal for development because UV erasure allows rapid firmware iteration during prototyping.
Recommended
Appliance Control Board
Low-cost appliance controllers - washing machines, microwave ovens, dishwashers - benefit from the PIC16C56A/JW's small footprint, low power consumption, and integrated peripherals. The 25-byte RAM and 1.5 KB EPROM are sufficient for simple wash-cycle state machines, while the 12 I/O pins drive relays, triac interfaces, and seven-segment LED displays without external mux logic. The 2.5 V to 6.25 V operating range tolerates unregulated supply rails common in white goods. The Watchdog Timer prevents the appliance from hanging in an unsafe state, and the PIC RISC core executes deterministic instruction cycles that simplify safety-software certification. The JW package is reserved for development; production builds use the plastic CERDIP or PDIP OTP variants.
Recommended
Educational Microcontroller Training Kit
The PIC16C56A/JW is widely used in university embedded-systems courses and self-study kits because of its simple Harvard architecture, transparent instruction set, and small 1.5 KB EPROM that students can fully master in a single semester. The JW windowed CERDIP package lets students erase their code with a UV lamp and re-program the part dozens of times, mirroring the iterative learning workflow of classic EPROM development boards. The 18-pin through-hole package is breadboard-friendly, and the 20 MHz maximum clock is fast enough to demonstrate real-time control loops. Reference designs in Microchip application notes drive LEDs, read switches, and generate PWM with nothing but the internal TMR0 peripheral.
Recommended
Sensor Front-End and Signal Conditioning
Simple sensor front-ends - temperature, humidity, and proximity - can be built around the PIC16C56A/JW with nothing more than a few op-amps and a UART or I/O bit-banged interface to the host. The 12-bit instruction width and 25-byte RAM are sufficient to implement linearization lookup tables for thermocouples and thermistors, while the 8-bit ADC-less I/O pin scheme supports external sigma-delta or integrating ADCs via TMR0 capture. The 2-level hardware stack keeps interrupt latency deterministic, which is critical for time-multiplexed sensor scanning. The Watchdog Timer is essential in remote sensor nodes that must recover autonomously from ESD events or supply transients.
Recommended
LED Driver and Display Sequencer
LED chaser boards, scoreboard displays, and architectural lighting fixtures are simple applications for the PIC16C56A/JW. The 12 I/O pins can drive 12 LEDs directly, or matrix-multiplex a larger array via external transistors, and the 20 MHz clock supports software PWM at frequencies above the flicker fusion threshold. The 1.5 KB EPROM holds long animation sequences, and the 25-byte RAM acts as the frame buffer for matrix refresh. Brown-out and Power-on Reset guarantee clean startup on hot-pluggable USB or wall-wart supplies. The Watchdog Timer recovers the MCU if a software bug stalls the LED refresh loop.
Recommended
Legacy Board Repair and Obsolete Inventory Sustainment
Many industrial and aerospace boards shipped in the 1990s and 2000s use the PIC16C56A in CERDIP and windowed CERDIP packages. The JW variant is specifically used by repair depots to replace damaged OTP parts with re-programmed windowed units, because UV erasure allows the depot to load the original firmware image onto a fresh windowed part before soldering it onto the board. The PIC16C56A/JW is also stocked by legacy-component brokers who sustain installed-base equipment with discontinued or NRND silicon. This application niche has limited but real demand, and is the primary reason the JW variant continues to be manufactured in low volumes.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C56A/JW — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C56/JW | PIC16C55/JW | PIC16C54/JW | PIC16C554/JW | PIC16C558/JW |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 18-CERDIP with UV window (JW) | 18-CERDIP with UV window (JW) - same | 18-CERDIP with UV window (JW) - same | 18-CERDIP with UV window (JW) - same | 18-CERDIP with UV window (JW) - same | 18-CERDIP with UV window (JW) - same |
| Program Memory | 1.5 KB (1K x 12) EPROM | 1.5 KB (1K x 12) EPROM | 768 B (512 x 12) EPROM | 768 B (512 x 12) EPROM | 896 B (512 x 14) EPROM | 3.5 KB (2K x 14) EPROM |
| Instruction Width | 12-bit | 12-bit | 12-bit | 12-bit | 14-bit | 14-bit |
| Maximum Clock | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Data RAM | 25 bytes | 25 bytes | 25 bytes | 25 bytes | 80 bytes | 128 bytes |
| I/O Pins | 12 | 12 | 12 | 12 | 13 | 13 |
| Watchdog Timer | Yes | Yes | Yes | Yes | Yes | Yes |
Key Differentiators
- Modern silicon revision with extended voltage range over original PIC16C56 (vs PIC16C56/JW)
- Largest baseline-family EPROM in the same 18-pin JW windowed package (vs PIC16C54/JW / PIC16C55/JW)
- True drop-in replacement with same package and pinout vs modern flash-based PICs (vs PIC16F54-I/P)
Design Notes
The JW windowed CERDIP cannot be reprogrammed in-circuit - erasure requires 20+ minutes of UV exposure through the quartz window. Do not use JW parts in production; choose the OTPEPROM equivalent (PIC16C56A-04/P or /SO) for production builds and keep JW only for development and legacy repair workflows.
Estimated: at 20 MHz and 5V supply, the PIC16C56A/JW typically draws 5-10 mA active and a few hundred microamps in sleep mode. Add a 100 nF decoupling capacitor as close as possible to VDD (pin 14) and a 10 uF bulk capacitor at the regulator output to handle inrush when the MCU exits sleep and clocks up to 20 MHz.
The 18-pin CERDIP JW package is through-hole with 2.54 mm (0.1 inch) pin pitch, so it fits standard breadboard and veroboard patterns. Keep the MCLR pull-up (typically 10 kohm) close to pin 4 to avoid spurious resets, and place the decoupling capacitor within 5 mm of VDD (pin 14). The crystal or resonator on OSC1/OSC2 should sit within 10 mm of pins 15-16 to minimize stray capacitance.
The 2-level hardware stack means the PIC16C56A/JW cannot nest more than 2 subroutines deep. Writing more than 2 CALL layers will corrupt the return PC and crash the firmware. Plan the call graph carefully, or refactor deeply nested code into iterative state machines. This is a well-known PIC16C5x baseline-family limitation versus the 8-level stack of PIC16F mid-range parts.
Compliance Information
RoHS, REACH, lead-free, and halogen-free status not present in the verified web data and should be confirmed with Microchip directly. AEC-Q100 is not applicable - the PIC16C56A/JW is not qualified for automotive safety use.
