Jhd-2x16-i2c Proteus !link! -

void main() I2C_Init(); I2C_Start(); I2C_Write(I2C_ADDRESS, 0x00); I2C_Write(I2C_ADDRESS, 'H'); I2C_Write(I2C_ADDRESS, 'e'); I2C_Write(I2C_ADDRESS, 'l'); I2C_Write(I2C_ADDRESS, 'l'); I2C_Write(I2C_ADDRESS, 'o'); I2C_Write(I2C_ADDRESS, ' '); I2C_Write(I2C_ADDRESS, 'W'); I2C_Write(I2C_ADDRESS, 'o'); I2C_Write(I2C_ADDRESS, 'r'); I2C_Write(I2C_ADDRESS, 'l'); I2C_Write(I2C_ADDRESS, 'd'); I2C_Stop();

| Problem | Likely Cause | Solution | | :--- | :--- | :--- | | LCD shows dark blocks (row of squares) | Contrast wrong, or LCD not initialized | Adjust pot; ensure lcd.init() and lcd.backlight() called | | No display, backlight only | Missing I2C communication | Check SDA/SCL pull-ups; verify address (0x20 vs 0x27) | | Garbage characters | RW pin floating or wrong 4-bit initialization | Tie RW to GND; use lcd.init() not lcd.begin() | | Proteus I2C debugger shows NACK | Wrong address or PCF8574 not powered | Set address exactly as A0-A2; check VDD | | "I2C Slave not responding" | Pull-ups missing | Add 4.7k resistors on SDA/SCL |

: The module usually defaults to address 0x27 or 0x3F . You can verify this in Proteus by double-clicking the PCF8574 component to check its pin configurations (A0, A1, A2).

// Turn on the backlight (simulation visual effect) lcd.backlight();