Re: ATN questions on the serial bus

From: Marko Mäkelä (
Date: 2003-06-09 10:00:55

Hello Nick,

> It should be remembered though that not all programs behave as
> nicely as the kernal.

True.  I'm going to make the C2N232 firmware addition as dummy as
possible, to achieve maximal flexibility.

By setting a breakpoint in the EOI handshake code in VICE, I found out
that no EOI handshake takes place when the bytes are sent under ATN.
This makes sense, because a low-to-high transition of the ATN line will
signal the end of transmission in that case.  Have you found any program
that performs EOI handshaking while sending bytes under ATN?

BTW, Jens Schönfeld provided me with some PLA equations.  I verified
them against the already archived copies, and also against the
64-kilobyte truth table dumps he sent me.  There are three additions:
1551, CBM II high profile (a.k.a. CBM 700 series), and P500 (not
decoded yet).  I have yet to check the 8296 equations made by André Fachat
against the truth table dumps made by Jens.


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