I tried CR/LF instead of just CR
I tried LF instead of CR
No change. On either of the 2 cables.
Then when switching cables I accidentally put the serial cable onto the header backward. Ground on the left. And I got local echo!
No status from the controller on return, or CR/LF, or LF ... but it echoed all of my characters.
So I did the same thing with the other cable. Umm .. same result?
Hyperterminal comes up with a terminal emulator of VT100 for me (likely because of some setting somewhere). Could that be affecting something?
Does using TX as GND make for some interesting voltage reference issues on the GND pin?
I think that the times when I saw jibberish on the screen with the older hex file that I may have had the header on the controller installed backward. When either cable is installed correctly now - there has never been a local echo, or the status line that the controller should be putting out.