Circuit

Connecting LCD Display (LCD1602) to the Raspberry Pi Pico

We will be using parallel interface in 4bit mode. Remaining Pins like D0 to D3 won't be connected.

LCD Pin Wire Pico Pin Notes
VSS
GND Ground
VDD
VBUS (5V) Power Supply
VO
GND or Potentiometer You can use Potentiometer or resistors to adjust the contrast. I placed two 1K resistors in between Ground and VO
RS
GPIO 16 Register Select (0 = command, 1 = data)
RW
GND Read/Write. Set '0' to write to display. If you want to read from display, set '1'
EN
GPIO 17 Enable
D4
GPIO 18 Data Bit 4
D5
GPIO 19 Data Bit 5
D6
GPIO 20 Data Bit 6
D7
GPIO 21 Data Bit 7
A
3V3(OUT) LED Backlight +
K
GND LED Backlight -

lcd1602