If you are writing a program on the Peggy 2, you can indeed use the standard commands– pinMode and digitalWrite –to take individual pins high or low. We also have a Peggy 2 library for Arduino that provides functions for lighting up individual LED locations. You can find the article about that– along with the rest of the Peggy 2 documentation –on our wiki: http://wiki.evilmadscientist.com/Peggy_2
However, I’m guessing (and please let me know if this is the case) you’re asking about is not actually writing programs on the Peggy 2 in the usual way, but instead sending serial commands that are designed to work with Firmata firmware. If that is what you want to do, you’ll need to upload the Firmata program to the Peggy 2 before you use it, and use the commands supported by Firmata.
