dcb: Is the reset pin bit 6 of Port C?... I thought the only part of the program that looped was the void loop() section... Oh, but every time I set PC6 low, the program resets and executes the code over again. Hahah...
mem: That's great that you think I should stick with using digitalWrite, but I don't really want to. I'd like to understand and be able to work with this device at a deeper level, so when I run into a problem that can be solved more effectively by direct port manipulation, I'll know how to tackle it.
I can see now that I should be setting the bits more carefully.
PORTD &= B00000011;
This will turn bits D7..2 Off, while leaving D1 and D0 alone (serial Rx, Tx).
PORTD |= B11111100;
Likewise, using the OR operator, I can turn bits D7..2 On.