Acorn IEEE488 interface

Tony Duell ard at p850ug1.demon.co.uk
Sun Dec 11 13:19:33 CST 2005


> 
> On 12/11/2005 at 4:54 PM Jules Richardson wrote:
> 
> >Eelco Huininga wrote:
> >> Does anyone have any documentation or software (other than IEEEFS 0.5 
> >> and NIEEE 0.2) for Acorn's IEEE488 interface for the beeb? 
> 
> On a slight tangent--is there really anything else required for
> medium-speed HPIB support other than a bidirectional 8-bit port with a few
> handshaking lines?  It seems to me that th Victor 9000 advertised IEEE-488

>From waht I rememebr you can do almost all the IEEE-488 stuff purely in 
software (the handshake is interlocked, in that something is changed by 
one device. then the other device changes some other line, then the first 
device can change a line, etc. THere's no chance of missing anything). I 
did say 'almost all' -- IIRC there's one thing you can't do like that, 
you need to do it in hardware. But it only takes a couple of gates.

Commodoe, and even HP, did do the HPIB interface in software in some of 
their machines. For example the HP82169 HPIL - HPIB interface contains a 
custom HPIB buffer chip, but it is just a buffer. The actual logic is 
handled by the microcontroller (8049 IIRC).

> capability with little more than a "dumb" parallel port.

IIRC, (and I don't haev the schematic in front of me) the Sirius (Victor 
9000) used a 6522 with some propper HPIB buffers (75160, etc). This was 
used for the Centronics parallel port, but with the right cable and 
software it could be used as an IEEE-488 port. Alas I've never seen the 
'right software'

-tony




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