The LCD Keypad input and output expansion board uses 2 lines of 16-character LCD, with adjustment and backlight, using 1 analog port to complete the input of 5 buttons, 1 reset button, and the unused IO ports are extended for backup. Make full use of the IO port.Occupied digital ports: PIN4 (DB4), 5 (DB5), 6 (DB6), 7 (DB7), 8 (), 9 (E), 10 (backlight control), analog key port A0. (LCD color is not specified, it will be shipped randomly.)Debugging of modules:Plug the LCD Keypad to the controller, then you need to download the LCD4Bit_mod.h (right-click and save as) library file to 0015/hardware/libraries, then compile the following test and download it to , for the first time using the LCD Keypad , First observe whether the LCD has displayed characters. If there are no characters displayed, the may be incorrect. You can use a flat-blade screwdriver to adjust RP1 (rotate clockwise) until clear characters appear.1602LCD maintechnical parameters:1.display capacity:16x2characters2.chip work ingvoltage:4.5-5.5V3.current:2.0mA(5.0V)4.module workingvoltage:5.0VLCD display: color random, 't accept the specified colorColour:black+greenMaterial:PCB + electronic componentsPackage Contents:1 x LCD Module Display ScreenOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.