Character LCDs are a fun and easy way to have your microcontroller project talk back to you. They are also common, and easy to get, available in tons of colors and sizes. At Adafruit they have written tutorials on using character LCDs with an Arduino (or similar microcontroller) but found out that the number of pins necessary to control the LCD can be restrictive, especially with ambitious projects. They wanted to make a 'backpack' (add-on circuit) that would reduce the number of pins without a lot of expense.
By using simple I2C and SPI input/output expanders the number of pins have been reduced, while still making it easy to interface with the LCD. Only 2 pins are needed for I2C, 3 for SPI. For Arduino and CircuitPython/Python users, an easy-to-use library is provided that is backwards compatible with projects using the '6 pin' wiring. This backpack comes with a 2-pin and 3-pin terminal block as shown (you can snap it together to make a 5-pin terminal and then solder it to the backpack for easy wiring).
This backpack will work with any 'standard' character LCD, from 8x1 to 20x4 sizes! As long as they have a 16-pin single-line connection header at the top. Note that it does not work with 16x2 OLED displays.
You can try to connect our RGB 16x2 or 20x4 LCDs, but this backpack will not control the RGB backlight so you'll have to use the backpack only for the 14 digital IO pins (pins #1-14) and connect the backlight pins (#15-#18) directly to your microcontroller with 4 extra wires for color/PWM control as if they were just an RGB LED.
NEW! As of February 8, 2023 - This backpack now comes with a big re-spin that makes lots of improvements:
Adafruit added a 3-5V boost circuit so you can use this backpack to control 5V LCDs even with 3V power and logic.
The contrast potentiometer is a lot nicer and easier to twist using a small screwdriver
Added SparkFun qwiic compatible STEMMA QT connectors for the I2C bus so you don't even need to solder the I2C and power lines. Just wire up to your favorite micro using a STEMMA QT adapter cable.
Functionality and size/shape are the same - mechanically and code-wise it is a drop-in replacement.
Advanced users can repurpose the backpack for general purpose I/O expansion: the MCP23008 has 8 i/o pins (7 are connected) with optional pull-ups, the SPI 74HC595 has 7 connected outputs.
Dit is een mooie upgrade voor standaard 16x2 LCD's. In plaats van alleen één kleur heeft deze LCD full colour RGB karakters op een donkere achtergrond!
Dit is een mooie upgrade voor standaard 20x4 LCD's. In plaats van alleen één kleur heeft deze LCD full colour RGB karakters op een donkere achtergrond!