I2C LCD1602
An LCD1602 is a 16-column by 2-row character display. The I2C backpack reduces the many LCD parallel pins to four useful module pins.
Part images
What it is
An LCD1602 is a 16-column by 2-row character display. The I2C backpack reduces the many LCD parallel pins to four useful module pins.
How students use it
Students use it to show text, sensor readings, menus, and status messages while keeping Pico GPIO usage low.
Pins and power
GND, VCC, SDA, SCL.
SunFounder labels VCC as 5V. Confirm the I2C pull-up behavior before connecting to Pico GPIO.
SunFounder notes SDA and SCL are pulled up to VCC. Default I2C address is usually 0x27, sometimes 0x3F. A0/A1/A2 pads can change the address.
Voltage and safety
Because the module is labeled 5V and I2C pull-ups connect to VCC, verify Pico-safe pull-up voltage before direct wiring.
Power off before changing address pads or wiring. Avoid shorting the backpack pins.
Module internals
Main component: PCF8574 I2C I/O expander on the LCD backpack, identified by SunFounder.
LCD1602 character LCD, PCF8574 backpack, backlight jumper cap, contrast potentiometer, and address pads A0/A1/A2.
Datasheet notes
SunFounder identifies the I2C backpack chip as PCF8574. The TI PCF8574 datasheet covers the I/O expander behind the LCD module.
Common libraries
Use machine.I2C plus an LCD1602/PCF8574 driver class. The driver should match the module address, usually 0x27 or 0x3F.
Common mistakes
Wrong I2C address, no common ground, swapped SDA/SCL, contrast turned until text disappears, backlight jumper removed, and unsafe 5V pull-ups on Pico I2C lines.