update: I realized I was looking at the wrong data line for the ft232 to the atmega on the scope. (stupid mistake). Now that I’m looking at the right one, I see that the bit stream is perfect going into the atmega. So I can rule out any errors on the computer side, or the ft232 chip. The problem has to be with the atmega. At 2 bytes, I get no framing errors, at 3 it’s very rare, and at 4+, it’s every time. However, even at 4 bytes, the bitstream is perfect going into the controller, all stop bits and star bits are present, but I still get framing errors, not on every byte though. I’m using peter fleury’s uart library on the atmega, which uses the receive interrupt to place data into a linked list buffer. I have a lot of other interrupts going as well, but the time to process one byte from the receive interrupt should be small. And if that was the problem, I would think I would get buffer overrun errors, not framing errors. Any ideas? Anyone???