Re: ATN questions on the serial bus

From: Marko Mäkelä (
Date: 2003-06-07 19:34:38

Hallo Ruud,
> EOI is used in three places:
> 1) sending the last byte under ATN
> 2) marking the last character of the filename (in 'LOAD"PARADROID",8 for
> example)
> 3) marking the end of a file 

I was confused by the fact that CIOUT has an one-byte buffer, and the last
byte (with EOI) is sent by the routine at $ee1c, which sends a byte under
ATN.  (In other words, this routine can send the deferred byte under EOI,
followed by the first command byte under ATN.)  This approach works, because
the CIOUT data streams are always "terminated" by an UNLISTEN command.

> I'm not sure if I detect the EOI marker in 1) but I surely make use of it
> with 2) and 3).

It could be that no EOI handshaking takes place if the ATN command consists
of a single byte.  I'll know this better, once I have implemented the commands
in the C2N232 firmware.  I already soldered a serial bus cable to a few unused
AT90S2313 pins on my first C2N232 prototype.


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