Improving row pin configuration flexbility. #23
When I was wiring up my atreus, I decided to use whatever pins were physically convenient. However, the firmware previously assumed all row pins were on PORTD, and I had one row pin on PORTC. This patch makes it easier to reconfigure pin settings for rows. As-is, it should be functionally identical if you wired as per the instructions; I'd appreciate if you could test it.
As a bonus feature, with this change the firmware doesn't clobber other pins while activating rows. This should facilitate use of any extra pins (I plan to use one for toggling LED backlighting on my board).