Re: Calling all DOS-heads

From: Jim Brain <>
Date: Fri, 30 Mar 2012 20:13:57 -0500
Message-ID: <>
On 3/30/2012 1:33 PM, Ingo Korb wrote:
>> I did send Jim a special firmware that will wait forever for DATA to
>> be acked. But perhaps it's never ACKed in this case since the ROM code
>> expects the circuit to handle it?
> Why do you expect correct operation when the hardware is broken?
Thanks for the suggestion about checking the address lines.

Looking at them, I determined that the code does eventually get to the 
ATN handler, but it takes 900mS or so to get there.

The reason the unconditional wait didn't work is that the sample code 
unconditionally waits for DATA to go low, but eventually something else 
overrode the unconditional wait and timed out the wait.  Outside the 
code loop, the ATN line was brought hi, and when the 900mS were up and 
the code got around to checking ATN, it was high.


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Received on 2012-03-31 02:00:05

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