PIC16C56T-HS/SO - 8-Bit 20MHz OTP MCU, 1.5KB | Microchip
MPN: PIC16C56T-HS/SO ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.39 | $6.39 |
| 10 | $6.1 | $61.00 |
| 100 | $5.65 | $565.00 |
| 500 | $5.2 | $2,600.00 |
| 1,000 | $4.85 | $4,850.00 |
PIC16C56T-HS/SO Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, non-volatile program memory, working RAM, and peripheral I/O on one die. The PIC16C5x family belongs to Microchip's original baseline RISC architecture (12-bit instruction word, 33 instructions) and sits within the broader hierarchy of: microcontroller -> embedded controller -> semiconductor IC. These classic OTP devices are one-time-programmable, meaning each unit can be programmed once during manufacturing or by the OEM but cannot be rewritten in the field, which historically lowered per-unit cost for high-volume embedded products.
Key features include 12 digital I/O pins arranged across two ports (PORTA 4-bit, PORTB 8-bit), a hardware 8-bit timer/counter with programmable prescaler, watchdog timer with on-chip RC oscillator, power-on reset, and a 4.5V to 5.5V commercial operating range. The device draws only a few mA active and supports power-saving SLEEP mode with wake-up via watchdog or external interrupt. The HS (high-speed) oscillator option accommodates 20 MHz crystal or ceramic resonator timing sources for designs requiring faster instruction throughput (200 ns instruction cycle).
Typical applications include legacy industrial control modules, appliance controllers, automotive body electronics, simple sensor interfaces, low-end remote controls, and white-goods user-interface boards. The wide software base and stable toolchain (MPLAB IDE, PICSTART+ programmer) make it a workhorse for cost-sensitive embedded designs that have shipped for decades and remain in maintenance.
When designing with this part, note that OTP memory cannot be updated after programming - firmware changes require a new part. The PIC16C56 has no in-circuit debugger interface, so emulator or ICE tools are needed for code development. Current consumption rises with clock frequency; plan decoupling accordingly.
Drop-in alternatives for PIC16C56T-HS/SO — 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-HS/SO (same form factor and footprint) — differing in Package, Program Memory Size, Timers, Maximum Clock Frequency, Program Memory Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C56-HS/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C56A-20/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C56A-04/SO
✅ Drop-In✓ In Stock
$1.4 / Unit
View Datasheet →PIC16C56T-HSI/SO
✅ Drop-In✓ In Stock
$1.78 / Unit
View Datasheet →PIC16C56-HSI/SO
✅ Drop-In✓ In Stock
$1.83 / Unit
View Datasheet →PIC16C56T-HS/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit PIC RISC (12-bit instruction word) |
| Family | PIC16C5x (PIC16C56) |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 1.5KB (1K x 12) |
| RAM | 25 bytes |
| Maximum Clock Frequency | 20 MHz |
| Instruction Cycle Time | 200 ns at 20 MHz |
| I/O Pins | 12 |
| Timers | 1 x 8-bit with prescaler |
| Watchdog Timer | Yes (on-chip RC oscillator) |
| Operating Voltage (Vdd) | 4.5 V to 5.5 V |
| Operating Temperature Range | 0C to +70C (commercial) |
| Oscillator Mode | HS (high-speed, 20 MHz crystal/ceramic) |
| Package | 18-SOIC (0.295 in / 7.50 mm width) |
| Mounting Type | Surface Mount |
| Packaging | Tape & Reel |
PIC16C56T-HS/SO Pin Configuration
| Pin 1 | RA2 — Bidirectional I/O, Port A bit 2 |
| Pin 2 | RA3 — Bidirectional I/O, Port A bit 3 |
| Pin 3 | NC — Not connected (per datasheet) |
| Pin 4 | MCLR/Vpp — Master Clear (reset) input / programming voltage |
| Pin 5 | Vss — Ground reference |
| Pin 6 | RB0 — Bidirectional I/O, Port B bit 0 (interrupt-on-change capable) |
| 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 output (crystal/resonator) |
| Pin 16 | OSC1 — Oscillator input (crystal/resonator/external clock) |
| Pin 17 | RA0 — Bidirectional I/O, Port A bit 0 |
| Pin 18 | RA1 — Bidirectional I/O, Port A bit 1 |
Typical Applications
PIC16C56T-HS/SO is suitable for 6 applications: Legacy Industrial Control Modules, Appliance User Interface Controllers, Automotive Body Electronics Modules, Remote Control and IR Transmitter Devices, Sensor Interface and Signal Conditioning, White Goods and Consumer Electronics Controllers.
Legacy Industrial Control Modules
The PIC16C56T-HS/SO fits long-life industrial control boards where firmware is fixed at production and the device has been qualified over decades of field deployment. Its 20 MHz HS oscillator drives 200 ns instruction cycles, sufficient for PLC scan loops, relay sequencing, and discrete sensor polling at sub-millisecond rates. The 12-bit instruction width keeps code compact for state-machine control logic, and the 12 I/O pins directly drive 24V industrial optocouplers through resistor networks. The wide 4.5V to 5.5V supply tolerates loosely regulated 5V industrial rails. Engineers maintaining installed equipment benefit from the device's known stable behavior and the mature MPLAB development toolchain that allows verification of legacy firmware against existing hardware.
Recommended
Appliance User Interface Controllers
The PIC16C56T-HS/SO suits washing machines, microwave ovens, and dishwasher user-interface boards where a small MCU scans a keypad, drives a multiplexed LED or LCD display, and runs a state machine for cycle control. The 12 I/O pins comfortably handle a 4x4 keypad matrix plus 7-segment display drivers, and the 8-bit timer with prescaler provides accurate debounce and timing functions. OTP memory locks the firmware version at production, which is ideal for compliance-locked appliance firmware. SLEEP mode reduces standby current to microamps when the appliance is in idle state, and the HS 20 MHz oscillator supports LED multiplexing refresh rates without flicker.
Recommended
Automotive Body Electronics Modules
The PIC16C56T-HS/SO appears in older automotive body controllers for window lift, mirror adjust, seat control, and simple lighting drivers. Its HS oscillator mode supports 20 MHz timing for multi-channel PWM-style sequencing, and the 1.5KB OTP memory stores fixed calibration tables for actuator timing. The commercial temperature range (0C to +70C) limits it to cabin modules rather than under-hood applications; for harsher environments the industrial-temperature PIC16C56T-HSI/SO variant should be selected. The 12 mA source/sink capability on I/O pins simplifies direct drive of small relays and LED indicators through current-limit resistors.
Recommended
Remote Control and IR Transmitter Devices
The PIC16C56T-HS/SO is well-matched to low-cost IR remote controls where a small MCU scans a 4x4 or 5x5 keypad matrix and generates 38 kHz carrier-modulated IR transmit waveforms. The HS 20 MHz oscillator divides cleanly into 38 kHz (526 instruction cycles per carrier half-cycle), enabling accurate IR protocol generation without external timers. The 1.5KB program memory stores multiple device protocol tables, and the 25-byte RAM is sufficient for transmit buffer and current-state tracking. SLEEP mode reduces idle current to enable long battery life on coin cells, with wake-up on keypad interrupt.
Recommended
Sensor Interface and Signal Conditioning
The PIC16C56T-HS/SO functions as a low-cost sensor interface MCU in HVAC, environmental monitoring, and process control subsystems. Its 12-bit ADC-free design (no on-chip ADC; relies on external or analog front-end) keeps cost minimal for digital sensor interfaces such as 1-Wire, I2C, or SPI peripherals. The HS oscillator mode at 20 MHz provides instruction throughput for serial protocol bit-banging or timer-based period measurement of pulse-train sensors. The 1.5KB OTP memory stores calibration constants and protocol handlers, while the watchdog timer ensures recovery from sensor line glitches.
Recommended
White Goods and Consumer Electronics Controllers
The PIC16C56T-HS/SO is deployed in white-goods controllers including refrigerator defrost timers, washing-machine motor sequencers, and dishwasher cycle controllers. Its commercial temperature grade suits indoor appliance environments, and the 12 I/O pins drive indicator LEDs, triac interfaces, and keypad scanners without external logic. The HS oscillator supports accurate timing of motor start/stop sequences and door-lock interlocks. OTP memory locks the firmware for regulatory compliance, and the watchdog timer recovers from line-voltage brownouts. The 18-SOIC package fits standard through-hole-to-SMT converter boards used in legacy appliance designs.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C56T-HS/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C56-HS/SO | PIC16C56A-20/SO | PIC16C56A-04/SO | PIC16C56T-HSI/SO | PIC16C56-HSI/SO |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 18-SOIC | 18-SOIC (same) | 18-SOIC (same) | 18-SOIC (same) | 18-SOIC (same) | 18-SOIC (same) |
| Program Memory | 1.5KB OTP | 1.5KB OTP | 1.5KB OTP | 1.5KB OTP | 1.5KB OTP | 1.5KB OTP |
| Maximum Clock | 20 MHz (HS) | 20 MHz (HS) | 20 MHz (HS) | 4 MHz | 20 MHz (HS) | 20 MHz (HS) |
| Operating Voltage | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 2.5 V to 6.0 V (wider) | 2.5 V to 6.0 V (wider) | 4.5 V to 5.5 V | 4.5 V to 5.5 V |
| Operating Temperature | 0C to +70C (commercial) | 0C to +70C (commercial) | 0C to +70C (commercial) | 0C to +70C (commercial) | -40C to +85C (industrial) | -40C to +85C (industrial) |
| Packaging Format | Tape & Reel | Tube | Tube | Tube | Tape & Reel | Tube |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete |
Key Differentiators
- Same die as PIC16C56-HS/SO with tape-and-reel carrier for high-volume SMT assembly (vs PIC16C56-HS/SO)
- 20 MHz HS oscillator enables 5x faster instruction throughput vs 04 MHz variant (vs PIC16C56A-04/SO)
- Commercial temperature grade (0C to +70C) suits consumer and indoor industrial use (vs PIC16C56T-HSI/SO)
Design Notes
Estimated: PIC16C56T-HS/SO active supply current is approximately 2.5 mA at 5V/20 MHz per the PIC16C5X datasheet DC characteristics. Add a 100 nF ceramic decoupling capacitor as close as possible to pins 14 (VDD) and 5 (VSS), plus a 10 uF bulk capacitor on the VDD rail. The HS oscillator mode draws additional current proportional to crystal ESR; choose a low-ESR crystal to keep total current below 5 mA in active mode.
OTP program memory cannot be rewritten after the programming cycle. If you need firmware updates, choose PIC16F54 or PIC16F57 instead. The PIC16C56 has no in-circuit debugger interface; development requires an ICE emulator or device programmer plus a programming adapter. The MCLR pin (pin 4) requires a 10 kohm pull-up to VDD for normal operation; without it the device will stay in reset. PORTA pins RA0-RA3 are shared with the device's startup configuration and may not be available immediately at power-up.
Route the HS oscillator traces (pins 15, 16) as short as possible and keep them away from high-current switching traces to minimize EMI coupling. Place the crystal or resonator within 5 mm of the OSC1/OSC2 pins and surround it with a grounded guard ring for noise immunity. Add a 1 Mohm parallel resistor across the crystal on high-ESR designs to ensure reliable startup. Keep digital I/O traces away from the analog supply if any analog signal conditioning circuitry is co-located on the board.
Compliance Information
Compliance status not explicitly stated in the verified web data for PIC16C56T-HS/SO. The part predates the widespread RoHS transition for OTP microcontrollers; non-RoHS variants may require tin-lead solder processes. Verify RoHS compliance with distributor documentation before placing orders for RoHS-restricted markets.
