Re: [avr-gcc-list] ADB-Project: USART and half duplex?

[Patrick Mächler v/o Valio]

Russell Shaw wrote:
> You should ask this question on avr-chat or some
> other hardware list.

Yes. I realised that I shouldn´t have asked here, but much too late :-(
The reason for was that I found a related topic from March 02 ("Student 
Needs Help With GCC Test 7 (UART) and the ATMEGA 128.") in the mailing 
list archive when I was searching for "Atmega128 UART". As I was a bit 
in a hurry I didn´t recognise that the main purpose of this list was for 
the gcc compiler (*selfpaddle*, it should have been really obvious).
I´m really sorry for this.


Ned Konz wrote:
> Then you will know that half duplex communications merely means that
> you aren't transmitting and receiving at the same time. Which is a
> constrained case of full-duplex, which the USART can handle quite 
well > because you can get an interrupt when the output buffer is empty
> (transmitting) and when the input buffer is full (receiving).

I was not sure if there there might be any interference if I would use 
the same line for uart input as for uart output...

> And I'm sure that you have read Apple's page on it, which says that
> you must obtain a license and device ID handler ID from them, and
> gives an address to write to (the license comes with a copy of the
> Apple Desktop Bus Specification):
> http://developer.apple.com/documentation/mac/Devices/Devices-204.html

Hm. AFAIK our project doesn´t concern this as we don´t intend to 
manufacture a device, but "to emulate" the macintosh ADB-Handling with a 
keyboard on a Crossbow MicaZ (so we give the mote inputs via the 
keyboard). I admit that it was not that clear in my first mail.


Thanks for all answers, files and links. They already helped us a lot.
I´ll start a new thread in "avr chat", if we need some more help.

Sincerely
Patrick Maechler
CS student Uni Basel (CH)

PS: For a german blog of the project see http://blog.stephansteiger.net