25 Mar
2002
25 Mar
'02
2:59 p.m.
From: Hans Franke <Hans.Franke(a)mch20.sbs.de>
I think Pete is right here. there was a wire you had
to add if
you used a 4118 (or 6116) instead of the 2114s. I have to grab
the kit documentation to veryfy this.
After checking the schematic I find that there is a link. "Use L1 for 1K
RAM, use L2 for 2K RAM." This tells me that when a 4118 or two 2114s are
used (or a 6116???) there is no need to change the jumper -- it's only
required when using a 2KB 2016 or equivalent.
Digging thru my ZX Stuff I found an _original_
"ZX81 2-K RAM" Kit *G*
Well, it is at least original over here, since it has
been sold by ISS,
the official distributor of ZX81 stuff in Germany.
Wow -- did you ever use the kit?
The kit konsists of a 24 pin socket and a NEC D446C-2
RAM
I'd guess this is the same as the 2016, and that you need to change the
link to L2 for it to work.
Glen
0/0
25 Mar
25 Mar
10:19 p.m.
> I think Pete is right here. there was a wire you
had to add if
> you used a 4118 (or 6116) instead of the 2114s. I have to grab
> the kit documentation to veryfy this.
After checking the schematic I find that there is a
link. "Use L1 for 1K
RAM, use L2 for 2K RAM." This tells me that when a 4118 or two 2114s are
used (or a 6116???) there is no need to change the jumper -- it's only
required when using a 2KB 2016 or equivalent.
Well, my instruction reads that L1 has to be set as soon as you have
a 4118 (or the otehr way around, it is only to be left out if you have
two 2114). Please check also the scanned assembly instructions at the
ZX Team pages (English Version)
http://home.t-online.de/home/p.liebert/f_zx81_e.htm
go to page 3, read the IMPORTANT paragraph
Digging thru
my ZX Stuff I found an _original_ "ZX81 2-K RAM" Kit *G*
Well, it is at least original over here, since it has been sold by ISS,
the official distributor of ZX81 stuff in Germany.
Wow -- did you ever use the
kit? The kit
konsists of a 24 pin socket and a NEC D446C-2 RAM
I'd guess this is the same as
the 2016, and that you need to change the
link to L2 for it to work. 
11:08 p.m.
Hi,
I have a old Vax computer with an Emulex UC08 in it, but I dont'have any
manuel, any UC08 original scsi cables, neither the pin out of the Emuler UC08
front connector
Can anybody help ?
Thanks
Etienne Stanus
Multitel ASBL
1 Avenue Nicolas Copernic
7000 Mons
Belgium
etienne.stanus(a)ieee.org
11:31 p.m.
If there's a configuration for the 2016, that should work OK with the 6116,
shouldn't it? It's well to keep in mind that it doesn't matter WHICH address
line goes to which address pin on the SRAM, only that it goes to an address
pin. Of course, some designs use addresses as chip selects, since they don't
use all of the address space. In those cases it's important to pay attention
to the association between addresses and the memory map.
Dick
----- Original Message -----
From: "Glen Goodwin" <acme_ent(a)bellsouth.net>
To: <classiccmp(a)classiccmp.org>
Sent: Monday, March 25, 2002 9:59 PM
Subject: Re: ZX81 and 6116
From: Hans
Franke <Hans.Franke(a)mch20.sbs.de>
I think Pete is right here. there was a wire you
had to add if
you used a 4118 (or 6116) instead of the 2114s. I have to grab
the kit documentation to veryfy this.
After checking the schematic I find that there is a link. "Use L1 for 1K
RAM, use L2 for 2K RAM." This tells me that when a 4118 or two 2114s are
used (or a 6116???) there is no need to change the jumper -- it's only
required when using a 2KB 2016 or equivalent.
Digging thru my ZX Stuff I found an _original_
"ZX81 2-K RAM" Kit *G*
Well, it is at least original over here, since it
has been sold by ISS,
the official distributor of ZX81 stuff in Germany.
Wow -- did you ever use the kit?
The kit konsists of a 24 pin socket and a NEC
D446C-2 RAM
I'd guess this is the same as the 2016, and that you need to change the
link to L2 for it to work.
Glen
0/0
26 Mar
26 Mar
10:16 a.m.
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7:36 p.m.
> line goes to which address pin on the SRAM, only
that it goes to an address
The same applies (of course) to data lines. Provided
each data lines goes
to _a_ data pin on the SRAM, it'll work. The data lines are bidirectional
on these chips, so if a bit is written on a particular line it'll be read
out on the same line. It doesn't matter what the RAM manufacturer called
it -- all data pins are equivalent on the chip.
Yep, true. The only situation I know where this has any
impact is if you use an in circuit RAM logger/emulator,
which picks the data from the RAM socket and of course
in all outputs assume that the lines are in 'standard'
use.
Gruss
H.
--
VCF Europa 3.0 am 27./28. April 2002 in Muenchen
http://www.vcfe.org/
11:39 p.m.
A lot of manufacturers have thought it "clever" to rearrange the address and
data lines, on an EPROM, for example, in order to obfuscate their firmware.
It's not rocket science to trace the CPU<=>EPROM hookup, though it's also
surprising how few people are willing to take the 10 minutes to do that. You
can get some surprises with RAM, however, and particularly if you are trying
to "program" a battery-backed RAM for purposes of emulating an EPROM, since
the order of the addresses and data normally doesn't matter at all.
Dick
----- Original Message -----
From: "Hans Franke" <Hans.Franke(a)mch20.sbs.de>
To: <classiccmp(a)classiccmp.org>
Sent: Wednesday, March 27, 2002 2:36 AM
Subject: Re: ZX81 and 6116
> > line goes to which address pin on the SRAM, only that it goes to an
address
The same applies (of course) to data lines.
Provided each data lines goes
to _a_ data pin on the SRAM, it'll work. The data lines are bidirectional
on these chips, so if a bit is written on a particular line it'll be read
out on the same line. It doesn't matter what the RAM manufacturer called
it -- all data pins are equivalent on the chip.
Yep, true. The only situation I know where this has any
impact is if you use an in circuit RAM logger/emulator,
which picks the data from the RAM socket and of course
in all outputs assume that the lines are in 'standard'
use.
Gruss
H.
--
VCF Europa 3.0 am 27./28. April 2002 in Muenchen
http://www.vcfe.org/
27 Mar
27 Mar
7:33 a.m.
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12:49 p.m.
Well, that's as good an excuse as any.
There are always "other" reasons. I happened to think of this one (a) because
I've been asked to do things that way, and (b) because someone recently
mentioned it. I've seen plenty of cases where it would have saved dozens of
vias to lay the board out without scrambling the address/data lines to the
EPROMs.
Dick
----- Original Message -----
From: "Tony Duell" <ard(a)p850ug1.demon.co.uk>
To: <classiccmp(a)classiccmp.org>
Sent: Wednesday, March 27, 2002 2:33 PM
Subject: Re: ZX81 and 6116
>
> A lot of manufacturers have thought it "clever" to rearrange the address
and
> data lines, on an EPROM, for example, in order to
obfuscate their
firmware.
Since it's so easy to figure out, I've always thought it was not done for
obfuscation, but to make it easier to lay the PCB out in the first place.
-tony
26 Mar
26 Mar
9:04 a.m.
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8258
days inactive
8260
days old
9 comments
5 participants
participants (5)
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acme_ent＠bellsouth.net -
ard＠p850ug1.demon.co.uk -
edick＠idcomm.com -
etienne.stanus＠ieee.org -
Hans.Franke＠mch20.sbs.de