If you run the simulation and the LCD remains blank (blue or green blocks, or nothing at all), here is the exclusive Proteus fix:
When working with the JHD2x16 (16x2 Character LCD) in Proteus, the standard parallel interface is straightforward but consumes a massive amount of microcontroller pins (at least 6 IO lines). The solution is the I2C Backpack (PCF8574). However, simulating this in Proteus often leads to frustration because the physical hardware behaves slightly differently than the software model. jhd2x16i2c proteus exclusive
Here is an exclusive deep dive into getting the JHD2x16 I2C configuration running perfectly in Proteus, covering the schematic, the hidden addressing logic, and the code. If you run the simulation and the LCD
Proteus sometimes requires explicit pull-up resistors on SDA & SCL (4.7kΩ each to +5V) for stable simulation, especially with multiple I2C devices. Proteus sometimes requires explicit pull-up resistors on SDA