RE: Weird behavior of C64 IEEE interfaces

From: Anders Carlsson (anders.carlsson_at_sfks.se)
Date: 2006-07-31 16:51:48

On Mon, 31 Jul 2006, ruud.baltissen@abp.nl wrote:

> maybe then I can find out what the starting address is.

As you already have figured out by now, it is SYS 45065. The first few
bytes are vectors to $B009 (start) and $B076 (restore), followed by
$42 $30 $EA $EA $EA. To me it looks like a CBM80 signature partly
padded out, like Commodore at an early stage had planned to autostart
the IEEE-488 interface, but decided against it.

For comparison, here is the EPROM dump from the Handic IEEE interface.
It also maps to $B000, but starts at 45056. Only the first 2K are
significant, the rest is garbage.

http://www.cbm.sfks.se/files/ieeerom.bin

Maybe someone finds it interesting to compare the VIC-1112 ROM dump
to this other interface and see if they have anything in common.

-- 
Anders Carlsson

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