LiquidCrystal_I2C Library Compatibility
PCF8574 I2C character LCD backpack. The pinned johnrickman API uses init().
- Pinned version
- 1.1.2
- Last matching compile evidence
- 2026-10-25
- Toolchain
- avr-gcc-wasm@0.2.0
- Primary headers
- LiquidCrystal_I2C.h
Dependencies and practical limits
PCF8574 I2C character LCD backpack. The pinned johnrickman API uses init().
Confirm the backpack address and pin mapping. A similarly named desktop library can expose a different API.
Use the exact pinned example and its Wire dependency before changing initialization calls.
Pinned direct dependencies: Wire
For a missing header, first compare the include to the example below. For an undeclared identifier, inspect the first diagnostic and selected board rather than changing every library version.
Board compile matrix
These are recorded compile/link results for the current build and exact source hash. UNTESTED means no matching proof, not an assumed pass. Memory values belong to the listed example and exclude runtime stack/heap or dynamic buffers.
| Board/profile | Result | Flash bytes | Static SRAM bytes | Last tested |
|---|---|---|---|---|
| Arduino Uno R3 — ATmega328P | PASS | 4006 | 275 | 2026-10-25 |
| Arduino Nano V3 — ATmega328P (new bootloader) | PASS | 4006 | 275 | 2026-10-25 |
| Arduino Nano V3 — ATmega328P (old bootloader) | PASS | 4006 | 275 | 2026-10-25 |
| ATmega328PB — 16 MHz | PASS | 4192 | 275 | 2026-10-25 |
| Arduino Mega 2560 — ATmega2560 | PASS | 4648 | 275 | 2026-10-25 |
| Arduino Leonardo — ATmega32U4 · native USB | PASS | 7378 | 416 | 2026-10-25 |
| Arduino Micro — ATmega32U4 · native USB | PASS | 7380 | 416 | 2026-10-25 |
| Arduino Pro Mini — 5 V · 16 MHz | PASS | 4006 | 275 | 2026-10-25 |
| Arduino Pro Mini — 3.3 V · 8 MHz | PASS | 4002 | 275 | 2026-10-25 |
Build: e0f6d304cce4ae0a0989a9b1300cbc1a21a595e5e3e7f57ed0ab3468ecf7940b. Library source hash: 9d9ff100cf467bd2c2e431f52ded41f0c2682b2b0fe41f1355c0578e6ecd3424. Compilation does not certify physical peripherals, timing or USB upload.
I2C LCD Hello World example
This is the actual pinned example available in Circuitera. Pin choices and wiring in a general example use Uno unless otherwise stated; review the selected board reference for other targets.
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2); // johnrickman 1.1.2 API; scan for your address.
void setup() { lcd.init(); lcd.backlight(); lcd.setCursor(0, 0); lcd.print("Hello, maker!"); }
void loop() { lcd.setCursor(0, 1); lcd.print(millis() / 1000); }
Projects using LiquidCrystal_I2C
Upstream source and documentation ↗
Pinned source archive (1.1.2) ↗
Read the test methodology →