Re: Mark IV Electronics Design

[Tom Droege <droege@wwa.com>]

Chris,

As outlined some time ago, this has long been done.  The problem was
to design an interface that was data push.  The receiving end has no 
control.  I did not want the read out from the chip to vary in speed as
would be the case with any computer interface.  i.e. from time to time
the computer wants the interface and holds things up.  So the design
is a straight byte parallel interface designed to go at up to a 20 MB or
so rate (for a short cable).  So it is not any standard interface.

Tom Droege

At 05:27 PM 1/8/98 -0800, you wrote:
>Tom Droege wrote:
>> 
>> This is mostly a reply to Grzegorz Pojmanski who is interested in using the
>> Mark IV electronics.  I am posting it to the group as there may be general
>> interest.   The status today is that there are rough drawings for
everything.
>> The connector details have not been worked out. 
>
>If you have not yet worked out the cable that feeds the
>memory board would you make it look like a printer
>interface.  Modern printer ports are bi-directional
>and very fast. (Just look at what a ZIP drive can do.) 
>If camera data could look like data comming
>back from a printer (or parallel interface ZIP drive)
>then at some point down the line
>we could just pull the memory card and plug the cable
>into an EPP printer port.  You've likely got the required
>signals already. Likely just need to get the pinout
>correct.  I think it is simple: ready, ack, and data. 
>One advantage of dropping the card is cost, but also, the
>PC gains access to the pixels quicker by several tens
>of seconds.  May help when you are tring to focus.
>
>I think the new ports bypass the ISA buss which should
>help, but also you don't need to write software to read
>from a standard port.
>
>Any rate if you copy the printer port pinout someone can
>experiment later.
>
>
>--Chris Albertson
>
>  chris@topdog.logicon.com                Voice:  818-351-0089  X127
>  Logicon RDA, Pasadena California          Fax:  818-351-0699
>
>