Originally Posted by knc1
Might be. I think these serial ports wil do 400K+ speed serial lines.
Flow control is nice to have at those speeds.
Anything that is a "driven ground" (signal output in low state, this is CMOS) might act like a not-so-good ground point.
Do you have access to an O'Scope to check it with?
Maybe we should get someone with a lot of "Google Credits" to look up how to use the PC Audio Mic-In (or Line-in, in this case) jack as a quick-and-dirty O'Scope.
I planned to do that "someday". It is probably AC coupled though. The XO/OLPC (one laptop per child) pc lets you select DC mode for the microphone input, and it has a scope program built-in.
But even AC coupled has its uses for changing signals, but not good for measuring static DC voltage levels.
I have Rigol (hacked, of course)... and a somewhat bulkier analog scope for when a DSO is not the right tool for the job. I think I was maybe 12 when I bought my first scope (AC coupled vacuum tube, back in the day)... ;-)