= Attaching a 4 digit 14 segment LED driven by the HT15k33 via I2C

This example code shows how to interface the Raspberry Pi Pico to one HT16K33 driven 4 digit 14 segment LED. The device used for development
uses VCC at 5v, but also allows the I2C voltage to be selected by connecting the vi2c pin to the appropriate voltage, in the Pico case 3v3 as the 
GPIO pins are not 5v tolerant.

NOTE: Other manufacturers make very similar devices with very similar names (e.g. Vinka VK16K33)). These may or may not work!

== Wiring information

Wiring up the device requires 5 jumpers, to connect VCC (3.3v), GND, vi2c (3v3), SDA and SCL. The example here uses I2C port 0, which is assigned to GPIO 4 (SDA) and 5 (SCL) in software. Power is supplied from the 3.3V pin.

WARNING: Some displays of this type are 5v with no option to select 3v3 for the I2c. If you wish to use a 5v display you will need to use level shifters on the SDA and SCL lines to convert from the 3.3V used by the RP2040. 

Connections on Raspberry Pi Pico board, other boards may vary.

   GPIO 4 (pin 6)-> SDA on LED board
   GPIO 5 (pin 7)-> SCL on LED board
   GND (pin 38)  -> GND on LED board
   5v (pin 40)   -> VCC on LED board
   3.3v (pin 36) -> vi2c on LED board

== List of Files

CMakeLists.txt:: CMake file to incorporate the example in to the examples build tree.
ht15k33_i2c.c:: The example code.

== Bill of Materials

.A list of materials required for the example
[[ht15k33_i2c-bom-table]]
[cols=3]
|===
| *Item* | *Quantity* | Details
| Breadboard | 1 | generic part
| Raspberry Pi Pico | 1 | https://www.raspberrypi.com/products/raspberry-pi-pico/
| ht16k33 based LCD panel | 1 | generic part
| M/M Jumper wires | 5 | generic part
|===
