Idea for a Charlieplex Kit 2.0 (6 I/O, 30 LEDs)

[chip273]

I did not really get why the charlieplex kit only uses 5 of the 6 I/O pins of the digispark. This gives us only 20 LEDs to write text, instead of the 30LEDs that would be possible with a 6 Pin Charlieplex shield.
So I have (quick and dirty) created a Eagle layout for a 6 pin Charlieplex Shield. I am not really into making/designing PCBs, so can anyone that knows about designing PCBs please look into it and tell me if I did any big mistakes ?

[semicolo]

Maybe because Voltage on PB5 is 3V instead of 5V, or because of PB3 1.5K onboard pullup?
Which pin isn't used on the official charlieplex shield?

[chip273]

I did not know it has a 1,5k pullup. P5 labeled with P5 D/A is unused on the charlieplex board, as well as all the 3 pins on the supply side.

[Bluebie]

If there's an unused pin, it might be cool to use it as IO to send strings in to the display! SoftwareSerial would do the job alright!

[semicolo]

Now that I read the datasheet a bit more to make the pinout diagram I know that P5 has a weak drive, it can only sink/source a few milli amps, so it's not a good candidate for charlieplexing.