ok, I see now, the timing is out. I uploaded blink to both the arduino and the tiny. then powered them up at the same time. They slowly go in and out of sync.how do I "read them back and verify them?"?Is this the next step I have to take?
OSCCAL = OSCCAL + 1;
Of course in your case what you really want to do is calibrate the oscillator to give reliable serial transmissions, so the Tiny Tuner is probably the most appropriate method for your situation.
If they slowly go in and out of sync, then it sounds like they are running at the "same" speed, one is just a bit faster. If the clock is off by 8 or 15MHz, the LED would blink way more slowly. It would be hugely obvious that one was twice as fast or even eight or sixteen times as fast. They wouldn't be close at all.
Yes just a wire, it keeps the Atmega in constant reset.The alternative is to remove the chip from the UNO, but I find that too risky.