Mostly just contains a ROM holding the text to be printed, and some logic to print the reset sequence and cursor position changes.
Connect up a character LCD according to the pinout, set the clock and hit reset. Run using an extra slow clock, as there is no internal clock divider. It’ll send data to the display as fast as it’s able to. After that, it should initialize the display and start printing stuff. Also, connect LEDs to LED0 and LED1 if you want some blinkenlights.
A 20x4 character LCD.
| # | Input | Output |
|---|---|---|
| 0 | CLK | RS |
| 1 | RST | E |
| 2 | EF0 | D4 |
| 3 | EF1 | D5 |
| 4 | EF2 | D6 |
| 5 | NC | D7 |
| 6 | NC | LED0 |
| 7 | NC | LED1 |