AVR-Chat

On Thu, 17 Mar 2005 17:45:39 -0500
 wg0z@aol.com wrote:
> To the best of my memeory, DDC makes a transceiver device
> that will interface fairly
> easily to most 16-bit or better microcontrollers. 

One site I found:
http://www.interfacebus.com/Design_Connector_1553.html

says this -
The data code shall be Manchester II bi-phase level. A
logic one shall be transmitted as a bipolar coded signal
1/0 (i.e., a positive pulse followed by a negative pulse).
A logic zero shall be a bipolar coded signal 0/1 (i.e., a
negative pulse followed by a positive pulse). A transition
through zero occurs at the midpoint of each bit time.. 
The transmission bit rate on the bus shall be 1.0 megabit
per second with a combined accuracy and long-term stability
of ± 0.1 percent (i.e., ±1000 hertz (Hz)). 

You would be pretty hard pressed to bit-bang 1MBit/second
in an AVR running 24MHz and converting manchester into a
serial bit stream. Some sort of PLD implementation probably
could do it. Didn't see any ICs right off. You would
definitely need a transceiver though an RS422/485
transceiver could probably do it since it is balanced and
does not have to be transformer coupled. The same web page
lists some IC sources.

Jim
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