9 Sep
2005
9 Sep
'05
10:15 a.m.
Hi,
Does anyone happen to have any data on the GPIB state machine, or perhaps a
GPIB slave interface implemented in LSTTL? I'm trying to rig up a CPLD to
take some of the load off the microprocessor in one of my projects, but the
GPIB is troublesome to say the least.
I've got a copy of the HP "Tutorial guide to HPIB" and "PET and the
IEEE488
Bus", but none of them cover the state machine...
Thanks.
--
Phil. | Acorn RiscPC600 SA220 64MB+6GB 100baseT
philpem at philpem.me.uk | Athlon64 3200+ A8VDeluxe R2 512MB+100GB
http://www.philpem.me.uk/ | Panasonic CF-25 Mk.2 Toughbook
... I may not always be perfect, but I'm always me.
9 Sep
9 Sep
11:53 a.m.
On 9/9/05, Philip Pemberton <philpem at dsl.pipex.com> wrote:
Hi,
Does anyone happen to have any data on the GPIB state machine, or perhaps a
GPIB slave interface implemented in LSTTL?
TNW made a serial interface for the PET that did not contain a
microprocessor. Perhaps you could search for schematics on that.
I've got a copy of the HP "Tutorial guide
to HPIB" and "PET and the IEEE488
Bus", but none of them cover the state machine...
With that as a guide, if you don't find an existing state machine,
there's plenty of information to generate one of your own. You could
even prototype one in software.
-ethan
8:44 p.m.
Hi,
Does anyone happen to have any data on the GPIB state machine, or perhaps a
I built a GPIB interface from TTL years ago, from what I remember it was
quite simple. Let me see if I can find schematics if you don't get more
useful replies.
I also designed a GPIB listener state machine in a GAL. Again I should
have the equations somewhere...
GPIB slave interface implemented in LSTTL? I'm
trying to rig up a CPLD to
take some of the load off the microprocessor in one of my projects, but the
GPIB is troublesome to say the least.
I've got a copy of the HP "Tutorial guide to HPIB" and "PET and the
IEEE488
Bus", but none of them cover the state machine...
Be _very_ careful if you use designs intended for the PET. The PET was
very forgiving in the timing of the peripherals. I have a commercial PET
RS232 interface that contains a UART chip, RS232 buffers, a few TTL chips
as SR latches to hold the talk and listen states, an EPROM as the code
converter (PERSCI-ASCII) and talk/listen address detector) and another
EPROM as the handshake control logic. Due to the fact there are no
latches in the latter section, the timing goes all over the place. It
works on the PET, it doesn't work on any HP machine I've tried it with.
-tony
10 Sep
10 Sep
10:25 a.m.
In message <m1EDtUI-000IytC at p850ug1>
ard at p850ug1.demon.co.uk (Tony Duell) wrote:
I built a GPIB interface from TTL years ago, from what
I remember it was
quite simple. Let me see if I can find schematics if you don't get more
useful replies.
That's great - thanks. I've dug up a copy of the TMS9914 datasheet, which
seems to be 8 pages of "this register bit does {X}, this one does {Y}".
Either I'm missing part of the datasheet, or it doesn't cover the GPIB states
at all.
I also designed a GPIB listener state machine in a
GAL. Again I should
have the equations somewhere...
I think I saw that somewhere.. A PET GPIB to Centronics adapter, right?
Be _very_ careful if you use designs intended for the
PET. The PET was
very forgiving in the timing of the peripherals. I have a commercial PET
RS232 interface that contains a UART chip, RS232 buffers, a few TTL chips
as SR latches to hold the talk and listen states, an EPROM as the code
converter (PERSCI-ASCII) and talk/listen address detector) and another
EPROM as the handshake control logic. Due to the fact there are no
latches in the latter section, the timing goes all over the place. It
works on the PET, it doesn't work on any HP machine I've tried it with.
Well, if it only just works on a 2MHz 6502, it's a sure bet it'll probably
fail at 8MHz.
I only wanted the IEEE488 part of the interface anyway - the CPU interfacing
gubbins2
Thanks,
--
Phil. | Acorn RiscPC600 SA220 64MB+6GB 100baseT
philpem at philpem.me.uk | Athlon64 3200+ A8VDeluxe R2 512MB+100GB
http://www.philpem.me.uk/ | Panasonic CF-25 Mk.2 Toughbook
... I'm in shape ... Round is a shape isn't it?
4:43 p.m.
I also
designed a GPIB listener state machine in a GAL. Again I should
have the equations somewhere...
I think I saw that somewhere.. A PET GPIB to Centronics adapter, right? Be _very_ careful if you use designs intended for
the PET. The PET was
very forgiving in the timing of the peripherals. I have a commercial PET
RS232 interface that contains a UART chip, RS232 buffers, a few TTL chips
as SR latches to hold the talk and listen states, an EPROM as the code
converter (PERSCI-ASCII) and talk/listen address detector) and another
EPROM as the handshake control logic. Due to the fact there are no
latches in the latter section, the timing goes all over the place. It
works on the PET, it doesn't work on any HP machine I've tried it with.
Well, if it only just works on a 2MHz 6502, it's a sure bet it'll probably
fail at 8MHz.
I only wanted the IEEE488 part of the interface anyway - the CPU interfacing
gubbins2
11 Sep
11 Sep
9 a.m.
In message <m1EECCS-000IyXC at p850ug1>
ard at p850ug1.demon.co.uk (Tony Duell) wrote:
Actaully, a PERQ centronics interface, but I can't
see any good reason
why it wouldn't work with a PET (although it doesn't do any kind of code
conversion.
That's the one! A couple of 16V8s and a 20V8, right?
No, you misunderstood me. There is no CPU involved in
this serial
adapter. The EPROM is the logic for the GPIB handashake. It's the GPIB
timing that's way out. It works with a PET as the other side of the link
because the PET does all the handshaking in software, so it's pretty
forgiving about timing problems. But this seiral adapter will _not_ with,
say, a 9914 as the other device on the bus..
Ah. Probably better to use that as an example of how not to design a GPIB
interface, I guess.
Thanks.
--
Phil. | Acorn RiscPC600 SA220 64MB+6GB 100baseT
philpem at philpem.me.uk | Athlon64 3200+ A8VDeluxe R2 512MB+100GB
http://www.philpem.me.uk/ | Panasonic CF-25 Mk.2 Toughbook
... Multitasking causes schizophrenia..
1:38 p.m.
Actaully, a
PERQ centronics interface, but I can't see any good reason
why it wouldn't work with a PET (although it doesn't do any kind of code
conversion.
That's the one! A couple of 16V8s and a 20V8, right? 
10 Sep
10 Sep
12:48 p.m.
I don't think page has been mentioned:
http://www.physics.brocku.ca/~edik/gpib/
There's a reference manual (254 pages!) for
a Nat. Semi. equivalent to the TMS9914.
I also have a copy of IEEE 488.2 somewhere,
email me if you think it mught be useful.
There's alo a GPIB FAQ around out there somewhere.
HTH,
Antonio
--
Antonio carlini
arcarlini at iee.org
6867
days inactive
6869
days old
7 comments
4 participants
participants (4)
-
arcarlini＠iee.org -
ard＠p850ug1.demon.co.uk -
ethan.dicks＠gmail.com -
philpem＠dsl.pipex.com