Hi all!
I am designing my own Arduboy using an ATMega32u4 (basing as much of my schematic of the ‘official arduboy’ as possible) and have a quick question, what is the purpose of the following LED’s, Are they necessary for the function of the Arduboy?:
Kindest regards,
Wheezer 
Others will know better than me, but the first three seem to be mostly decorative “fun” lights used next to the screen, and can be controlled by games. I’ve seen some games use them, but rarely as part of gameplay. They look cool shining behind the clear cover, it lights up the whole device. It’s kind of fun when you complete a level and the lights all flash.
The last two are, I’m pretty sure, related to indicating transferring data (they’re yellow and green I think?). The bootloader will light them up when the host device is reading or writing (respectively). They’re helpful to know the device isn’t just locked up, as the bootloader is generally unresponsive during host data transfers.
Someone else, please correct me if I’m wrong!
The red, green and blue LEDs are actually the individual LEDs in a single common anode RGB LED. Software written for the Arduboy can use the RGB LED for any purpose. The pins they are attached to can all provide PWM analog output, so many colours and intensities can be produced.
The RX and TX LEDs are the standard ones provided on the Arduino Leonardo, which the Arduboy is based on. As @haloopdy said, they are used to indicate when data is being transmitted and received over the USB port. However, they can also be controlled by user programs. For example the Arduboy2 Library’s nextFrameDEV() function uses the TX LED to indicate that the program can’t keep up with the desired frame rate (for development purposes).
Note that the new Arduboy Mini won’t include the TX and RX LEDs but the signals are brought out to pads so that they could be added fairly easily, if desired.
Okay awesome! so it seems like none of them are entirely essential to the function of the device. I would like to test one of the games that utilizes the RBG function, can you recommend one?
Thanks very much!!
Road Trip by PPOT is nice. When you start the race it should flash red → amber → green (code is here).
To test all the different LEDs, I also like to use Arduboy Assistant by @crait.
How about the RGBled example program included with the Arduboy2 library? If using the Arduino IDE:
File > Examples > Arduboy2 > RGBled
