PIC16C55/JW - 8-bit 4MHz 768B EPROM MCU 28-CDIP | Microchip
MPN: PIC16C55/JW β End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $18.5 | $18.50 |
| 10 | $16.75 | $167.50 |
| 100 | $14.2 | $1,420.00 |
| 500 | $12.1 | $6,050.00 |
| 1,000 | $10.4 | $10,400.00 |
PIC16C55/JW Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU, program memory, working RAM, and peripheral I/O onto one piece of silicon. The PIC16C5X family is the original baseline architecture of Microchip's PIC line, predating mid-range and enhanced cores. The 12-bit program word width (vs. 14 or 16 bits on later PIC16 families) is the defining trait of this baseline series. Within the power-management / embedded-control taxonomy, the PIC16C55 sits in the hierarchy: MCU -> 8-bit microcontroller -> baseline PIC16C5X family -> UV-EPROM variant.
Key differentiating features include the JW windowed ceramic package, which is the only form factor in the family that allows UV erasure - making the part suitable for development, education, and low-volume production where firmware iteration is expected. The 512-word program space, 24-byte RAM, and 12-bit instruction width match every other PIC16C55 speed grade (RC, XT, LP, HS), meaning code is portable across oscillator options. The 20 I/O pins support direct LED drive and simple digital interfacing.
Technically, the PIC16C55 uses a Harvard architecture with separate program and data buses, a 2-stage pipeline, and 33 single-word single-cycle instructions. The part is fully static, allowing the clock to be stopped without losing register state. Power consumption is dominated by oscillator choice: an RC oscillator draws roughly 2 mA at 5V/4MHz, while the LP (low-power) crystal option drops active current to well under 1 mA, supporting battery-instrumented designs. There is no internal ADC, no UART, no PWM, and no on-chip oscillator, keeping die area (and price) minimal for simple control loops.
Typical applications include educational development platforms, legacy industrial controllers, simple appliance timers, hobby robotics, and replacement boards in equipment originally designed around the PIC16C5X baseline core. The PIC16C55/JW is most often deployed where the engineering team already has code compiled for this architecture or where a UV window is needed during firmware bring-up. Engineers often migrate the JW into a one-time-programmable (OTP) ceramic or plastic DIP variant for production volume.
When designing with this part, note that the JW windowed package is not hermetically sealed in the conventional sense; the quartz window requires a UV-erasure socket for re-programming. For volume production, choose the equivalent OTP part (PIC16C55/P or PIC16C55-I/P) once code is final, since the JW package carries a substantial cost premium and reduced mechanical robustness. Designers should also budget for a 4 kohm pull-up on the MCLR reset pin and bypass capacitors within 1 cm of VDD/VSS, per Microchip baseline PIC guidelines.
Drop-in alternatives for PIC16C55/JW β 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 PIC16C55/JW (same form factor and footprint) β differing in Core Architecture, I/O Pins, Maximum Clock Frequency, Package, Program Memory Size.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC16C55-LP/JW
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
PIC16C55-XT/JW
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
PIC16C55-RC/JW
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
PIC16C55-HS/JW
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
PIC16C54C/JW
β Drop-Inβ In Stock
$4.95 / Unit
View Datasheet βPIC16C55/JW Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC (baseline) |
| Program Memory Type | UV-Erasable EPROM |
| Program Memory Size | 768 B (512 x 12) |
| RAM | 24 B |
| Maximum Clock Frequency | 4 MHz |
| Instruction Set | 33 single-word instructions, 12-bit width |
| I/O Pins | 20 |
| Timers | 1 x 8-bit (TMR0) |
| Watchdog Timer | Yes |
| ADC | None |
| UART | None |
| Interrupt Sources | External (no interrupt-on-change) |
| Supply Voltage (VDD) | 2.5 V to 6.25 V |
| Operating Temperature | 0 C to +70 C (commercial, /JW) |
| Package | 28-pin CDIP (side-brazed with UV window) |
| Mounting Type | Through-Hole |
| RoHS Status | Non-compliant (contains leaded glass window) |
PIC16C55/JW Pin Configuration
| Pin 1 | RA0 β Port A bit 0 (digital I/O) |
| Pin 2 | RA1 β Port A bit 1 (digital I/O) |
| Pin 3 | RA2 β Port A bit 2 (digital I/O) |
| Pin 4 | RA3 β Port A bit 3 (digital I/O) |
| Pin 5 | RA4/T0CKI β Port A bit 4 / Timer 0 clock input |
| Pin 6 | MCLR β Master Clear (active-low reset, requires 4 kohm pull-up) |
| Pin 7 | VSS β Ground reference |
| Pin 8 | OSC1 β Oscillator input (crystal/RC) |
| Pin 9 | OSC2 β Oscillator output (crystal mode) |
| Pin 10 | RB0 β Port B bit 0 (digital I/O) |
| Pin 11 | RB1 β Port B bit 1 (digital I/O) |
| Pin 12 | RB2 β Port B bit 2 (digital I/O) |
| Pin 13 | RB3 β Port B bit 3 (digital I/O) |
| Pin 14 | RB4 β Port B bit 4 (digital I/O) |
| Pin 15 | RB5 β Port B bit 5 (digital I/O) |
| Pin 16 | RB6 β Port B bit 6 (digital I/O) |
| Pin 17 | RB7 β Port B bit 7 (digital I/O) |
| Pin 18 | VDD β Positive supply (2.5-6.25 V) |
| Pin 19 | RC0 β Port C bit 0 (digital I/O) |
| Pin 20 | RC1 β Port C bit 1 (digital I/O) |
| Pin 21 | RC2 β Port C bit 2 (digital I/O) |
| Pin 22 | RC3 β Port C bit 3 (digital I/O) |
| Pin 23 | RC4 β Port C bit 4 (digital I/O) |
| Pin 24 | RC5 β Port C bit 5 (digital I/O) |
| Pin 25 | RC6 β Port C bit 6 (digital I/O) |
| Pin 26 | RC7 β Port C bit 7 (digital I/O) |
| Pin 27 | VSS2 β Secondary ground (substrate, bonded internally) |
| Pin 28 | NC β Not connected (no internal bond, per datasheet) |
Typical Applications
PIC16C55/JW is suitable for 6 applications: Embedded Education and Training Kits, Legacy Industrial Control Replacement, Hobby Robotics and Simple Appliance Timers, UV-EPROM Development Reference Platform, Low-Volume Specialty Instrumentation, Software Defined Radio Companion Controller.
Embedded Education and Training Kits
The PIC16C55/JW is a foundational teaching vehicle in undergraduate embedded systems and microcontroller courses because the UV window lets students re-flash code dozens of times on a single device. With 768 bytes of EPROM (512 x 12 words), 24 bytes of RAM, and 20 I/O pins, the part supports realistic laboratory exercises in instruction-set architecture, register-file mapping, and bit-manipulation I/O without overwhelming beginners with peripherals. The 33-instruction baseline RISC core lets instructors trace every cycle, and the JW package pairs with a standard 28-pin DIP socket for breadboard-friendly labs. The 4 MHz oscillator is fast enough to demonstrate debouncing, polled-key scanning, and simple state machines; slow enough that timing relationships remain visible on an oscilloscope. Compared with newer PIC16F parts, the PIC16C55/JW trades Flash convenience for cycle-deterministic 12-bit instruction behavior that textbook exercises can analyze by hand.
Recommended
Legacy Industrial Control Replacement
The PIC16C55/JW remains in service as a long-life spare for industrial equipment originally shipped in the 1990s, where control firmware was written against the 12-bit baseline PIC16C5X core and is preserved in EPROM. Plants with multi-decade support obligations use the JW windowed package to clone firmware onto refurbished parts during scheduled shutdowns. The 20 general-purpose I/O lines can drive relays, optocouplers, and indicator LEDs directly through current-limit resistors, and the 4 MHz instruction rate sustains simple PID loops at typical thermostatic and pressure-control update rates. Because the PIC16C5X lacks a UART or ADC, legacy systems route analog signals through external 8-bit ADCs and handle inter-MCU communication via bit-banged I/O. The JW package allows field reprogramming for obsolete machine retrofits, but for new production Microchip now ships the equivalent PIC16C55-I/P OTP variant.
Recommended
Hobby Robotics and Simple Appliance Timers
Hobby robotics projects and consumer appliance timers - dishwasher delay modules, fan controllers, irrigation valves - rely on the PIC16C55/JW for its predictable timing and I/O density. The single 8-bit TMR0 counter plus software loops produces PWM and software-serial output adequate for RC-servo control or IR remote encoding. The 20 I/O pins can drive seven-segment displays, keypads, buzzer drivers, and triac-fired loads without external logic. The commercial temperature grade (0 to +70 C) and 2.5-6.25 V supply range suit indoor consumer devices; battery-powered versions use the LP oscillator to drop active current below 1 mA. The JW window allows makers to iterate firmware in-circuit with a UV eraser; once a design stabilizes the same code moves to the cheaper PIC16C55-I/P or PIC16C55T-I/SS SMD variant for permanent installations.
Recommended
UV-EPROM Development Reference Platform
The PIC16C55/JW is the canonical reference target for companies validating UV-EPROM programmer sockets, eraser exposure times, and 12-bit baseline firmware flows before committing to higher-density PIC16C55 OTP variants. The transparent window makes it possible to confirm that programming and erasure are functioning across all 512 instruction words in a single device cycle. Engineering teams use the JW part on development boards where programmers (MPLAB PM3, Xeltek SuperPro, Dataman 48Pro) are debugged; once the production programmer is calibrated the same firmware image programs onto PIC16C55-I/P OTP plastic DIP parts for high-volume manufacturing. The windowed variant also helps calibrate UV eraser exposure intensity and timer curves in contract-manufacturing facilities.
Recommended
Low-Volume Specialty Instrumentation
Low-volume specialty instruments - laboratory data loggers, museum environmental sensors, agricultural irrigation controllers - deploy the PIC16C55/JW where small BOM cost, deterministic firmware, and long-term availability of source code outweigh the convenience of modern Flash microcontrollers. The Harvard architecture with separate program and data buses prevents data-memory corruption from code-fetch glitches, an advantage in electrically noisy installations such as greenhouse or barn environments. The 4 MHz clock and 12-bit instruction word support single-precision math in firmware with predictable cycle counts. The commercial 0 to +70 C range is acceptable for indoor instrumentation; for outdoor use the PIC16C55-I/JW (-40 to +85 C) or PIC16C55-E/JW (-40 to +125 C) industrial / extended grades are substituted into the same JW 28-CDIP footprint.
Recommended
Software Defined Radio Companion Controller
In educational Software Defined Radio (SDR) platforms the PIC16C55/JW frequently serves as a front-panel controller that handles button debouncing, LED indicators, LCD enable lines, and rotary-encoder quadrature decoding while the actual signal processing is performed by a dedicated DSP or FPGA. The 20 I/O lines suffice for a 4 x 4 keypad, an HD44780 16x2 LCD, three rotary encoders, and a status-LED bank. The deterministic instruction cycle allows accurate timing of encoder sampling without timer overflow drift, an issue more common in larger Flash MCUs with multi-cycle interrupt entry. The single 8-bit TMR0 is enough for sample-based debouncing and slow serial output. The JW windowed package supports frequent firmware updates during SDR algorithm tuning; once a working build is locked, the code transitions to an OTP PIC16C55-I/P for permanent radio installations.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C55/JW β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C55-LP/JW | PIC16C55-XT/JW | PIC16C55-RC/JW | PIC16C55-HS/JW | PIC16C54C/JW |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-CDIP (JW, windowed) | 28-CDIP (JW, windowed) - same | 28-CDIP (JW, windowed) - same | 28-CDIP (JW, windowed) - same | 28-CDIP (JW, windowed) - same | 28-CDIP (JW, windowed) - same |
| Program Memory | 768 B (512 x 12) | 768 B (512 x 12) - same | 768 B (512 x 12) - same | 768 B (512 x 12) - same | 768 B (512 x 12) - same | 512 B (512 x 12) - 33% smaller |
| RAM | 24 B | 24 B - same | 24 B - same | 24 B - same | 24 B - same | 24 B - same |
| Max Clock Frequency | 4 MHz | 200 kHz (LP oscillator grade) | 4 MHz (XT oscillator grade) | 4 MHz (RC oscillator grade) | 4 MHz (HS oscillator grade) | 4 MHz |
| Supply Voltage | 2.5 V to 6.25 V | 2.5 V to 6.25 V - same | 2.5 V to 6.25 V - same | 2.5 V to 6.25 V - same | 2.5 V to 6.25 V - same | 2.5 V to 6.25 V - same |
| I/O Pins | 20 | 20 - same | 20 - same | 20 - same | 20 - same | 20 - same |
| Memory Type | UV-EPROM (windowed) | UV-EPROM (windowed) - same | UV-EPROM (windowed) - same | UV-EPROM (windowed) - same | UV-EPROM (windowed) - same | UV-EPROM (windowed) - same |
| Operating Temperature | 0 C to +70 C (commercial) | 0 C to +70 C - same | 0 C to +70 C - same | 0 C to +70 C - same | 0 C to +70 C - same | 0 C to +70 C - same |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete |
Key Differentiators
- UV-erasable window for firmware iteration (vs PIC16C55-I/P (OTP plastic DIP))
- Largest EPROM density in the PIC16C5X baseline family (vs PIC16C54C/JW)
- Fully static CMOS design allows clock stop (vs Dynamic-logic 8051-class MCUs)
Design Notes
Do not assume PIC16C55/JW firmware is portable to PIC16F54 or PIC16F55 - the instruction-set width differs (12-bit baseline vs. 14-bit mid-range), and the PIC16F54 uses a 4-clock instruction cycle versus 2 on the baseline. Recompile from source. Also, do not design new products around the JW windowed package for volume production; the ceramic side-brazed CDIP is 4-6x the price of the equivalent PIC16C55-I/P OTP plastic DIP and has poorer mechanical shock tolerance. Migrate to the OTP variant once firmware stabilizes.
Power consumption is dominated by oscillator configuration. Estimated: at VDD = 5 V and 4 MHz, the part draws roughly 2 mA active in XT mode and approximately 1.6 mA in RC mode. For battery-powered designs, select the LP oscillator variant (PIC16C55-LP/JW) which drops active current to under 1 mA at 200 kHz. Place a 0.1 uF decoupling capacitor within 1 cm of VDD (pin 18) and VSS (pin 7); add a bulk 10 uF electrolytic on the same rail. The MCLR pin (pin 6) requires a 4 kohm pull-up to VDD - omitting it prevents reliable reset on power-up.
For UV erasure compatibility mount the PIC16C55/JW in a precision 28-pin DIP socket with a textured, open-frame top (e.g., Aries 28-6552-10) so the quartz window is exposed to UV light without removing the part. Avoid conformal coating over the window - it blocks erasure. If the design must tolerate field shock and vibration, use pin-staked DIP sockets (Mill-Max 110-13-328-41-001000) or migrate the JW prototype to a JW-equivalent plastic-DIP windowed variant when available. Route crystal traces on the same PCB side as OSC1/OSC2 with short, ground-guard traces to minimize oscillator noise coupling into analog or RF sections of the board.
The PIC16C55/JW is a digital-only device with no analog peripherals, so noise-isolation layout concerns are minor. The only critical layout constraint is the oscillator section: keep OSC1 (pin 8) and OSC2 (pin 9) traces under 1 cm, surround them with a ground pour, and place the crystal/ceramic resonator and its load capacitors (typically 15-33 pF each) within 5 mm of the IC. Avoid routing any high-frequency switching signal (relay coils, triac gate drives) within 5 mm of the oscillator loop. Add a 100 ohm series resistor between the MCU and any I/O pin driving more than 10 cm of cable to limit ringing.
Compliance Information
JW ceramic-DIP package contains a leaded-glass window and is therefore non-RoHS-compliant; the silicon die is lead-free but the package prohibits use in RoHS-only assemblies. REACH SVHC declarations for the die materials have been filed by Microchip. Not qualified to AEC-Q100; for automotive designs the active-production PIC16F57 or PIC16F1939 baseline-compatible parts should be considered instead.
