Weird IEEE behaviour
Date: 2006-09-16 21:29:44

Hallo allemaal,

Some time ago I reported about some problems with IEEE interfaces for the 
C64 in combination with my CBM-HD emulator. Today I met Dirk Klettke in 
Kerkrade and he brought his IEC2IEEE inteface with him, please see 
<>. He wanted to demonstrate the device but had no IEEE drive of 
his own with him. I only had my 8296D with me and tried that one. That 
worked fine. First finding: in contrary to the C64 a CBM doesn't block the 
IEEE bus. Very nice :)  So we connected CBM-HD as well. The IEC2IEEE didn't 
see CBM-HD :( Worse, it didn't see the 8250 of the 8296D either. 
Disconnecting the cable to my PC restored things to normal. So our 
conclusion was: my piece of hardware was blocking the bus in one or another 

But now the astonishing thing: after reconnecting the cable, the 8296D had 
no troubles at all accessing his onboard drive as well as my emulated ones 
!!!! I even connected my cable to another, unmodified, LPT-port, set its 
controlport as it should be IMHO, and the same happened again: 8296D works 
fine, IEC2IEEE doesn't work.

Only looking at this case I would say the Atmel is not able to drive the 
LPT-bus. But what about the interfaces I mentioned before? These had TTL 
and even original IEEE drivers! (Sorry, had no time to check the other 
intefaces in combination with the 8296D, but will certainly do that when 
I'm back from my course)

Any idea, comment is more then welcome !!!

PS: I'm on a course from tommorow on and won't be able to react until 

   / __|__
  / /  |_/     Groetjes, Ruud
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