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Mike Pepe | 1 Jul 2005 18:02
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[Color Computer] Difference between 86 and 87 GIME

The only difference I'm aware of was corrected timing that fixed some 
problems with 150nS DRAMs. Is there anything else of significance 
between the two revisions that makes the 87 really much better than the 86?

If you're using 120nS or faster DRAMs, does it matter which version you 
have?

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Paul T. Barton | 1 Jul 2005 20:11
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Re: [Color Computer] Difference between 86 and 87 GIME

For me, I dunno. Am using 60ns DRAMS.

Paul

--- Mike Pepe <lamune@...> wrote:

> The only difference I'm aware of was corrected
> timing that fixed some 
> problems with 150nS DRAMs. Is there anything
> else of significance 
> between the two revisions that makes the 87
> really much better than the 86?
> 
> If you're using 120nS or faster DRAMs, does it
> matter which version you 
> have?
> 
> 
> 
> Brought to you by the 6809, the 6803 and their
> cousins! 
> Yahoo! Groups Links
> 
> <*> To visit your group on the web, go to:
>    
> http://groups.yahoo.com/group/ColorComputer/
> 
> <*> To unsubscribe from this group, send an
> email to:
>     ColorComputer-unsubscribe@...
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j_e_daggett | 1 Jul 2005 20:41
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[Color Computer] Re: Difference between 86 and 87 GIME

--- In ColorComputer@..., Mike Pepe <lamune <at> d...> wrote:
> The only difference I'm aware of was corrected timing that fixed some 
> problems with 150nS DRAMs. Is there anything else of significance 
> between the two revisions that makes the 87 really much better than
the 86?
> 
> If you're using 120nS or faster DRAMs, does it matter which version you 
> have?

******

As far as I know there is no obvisous way to tell the GIME chip what
speed the dram is. With that in mind to my knowledge the GIME chip is
set for one speed only. That is for the slowest of dram and that would
be 150 nS dram. Using 120 or 100 nS dram will be still operating them
at 150nS access speed. 

Dram access speeds are speced from the time the RAS line goes low to
the time data is ready for a read cycle. The main timing problem of
the 86 GIME was with Trc. This is the total cycle time of a read or
write cycle. Most manufacturers speced this time at 260 nS minimum.
SOme went has high as 280nS minimum. At  high speed(1.78 MHz) one half
the E clock time is 279nS. The GIME to read from video ram and then
switch the multiplexor back to the CPU address has only 19 nS time to
spare. Any jitter or poor synchronization can cause problems. 

This is an understanding I have of the GIME's operation. There  were
someother internal cleanups that may have taken place in other spots
of the GIME with the 87 version.
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j_e_daggett | 1 Jul 2005 20:49
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Re: [Color Computer] 1M simms in Cloud9 SIMM upgrade kit

--- In ColorComputer@..., "Paul T. Barton" <idezilla <at> y...>
wrote:
> Mike,
> 
> Still, I think that it can be done.
> By using CAS before RAS DRAM internal refreshing.
> The DRAMs keep their own internal counter
> for this. Just swap RAS for CAS,
> only during HSync and/or VSync.
> I know that this works, I use it.
> 
> I could give out a partial schematic for this,
> if you want a look-see.
> 
> Paul
********

Paul 

you can use CAS before RAS. During that period most page mode drams
allowed ras only,cas before ras and hidden refresh. The problem I see
with CAS before RAS is that you slow the aceess time down by 1/2. That
is a 150 nS access time becomes a 225nS access time dram. The way I
understand dram speed specs is that access time is determined from
when the RAS line gose low and the data is ready for reading on the
read cycle. CAS to data ready is half that of RAS to data ready.
Putting the CAS before the RAS increases access time. In the computer
world where speed is the holy grail, slowing down access is blasphemy. 

james
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Michael Wayne Harwood | 1 Jul 2005 21:57

Rainbow Magazine Article/Program List

I am looking for a comprehensive article/program list for the Rainbow
magazine.  I have seen references to "Steve McCoy's" site, but it looks like
it is defunct.  I can scan, OCR, and proof-read articles lists from the
magazines themselves in necessary, but I thought it might be nice not to
have to.  

Can anyone help?

Regards,
Michael Harwood

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Paul T. Barton | 1 Jul 2005 22:20
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Re: [Color Computer] 1M simms in Cloud9 SIMM upgrade kit

j_e_daggett,

You missed the part where I stated that
this CAS/before/RAS refresh was during
video (only!) and during HSync and
VSync. So, no slowdowns at all!
(Must have been on another email,
"somewhere".)

Check the URL:
http://home.wwdb.org/irgroup/scope.html
Shows the timing from a TEK 'scope
during non-screen video time.
(another freebie).

Paul :-) Happy Friday!

--- j_e_daggett <j_e_daggett@...> wrote:

> --- In ColorComputer@..., "Paul T.
> Barton" <idezilla <at> y...>
> wrote:
> > Mike,
> > 
> > Still, I think that it can be done.
> > By using CAS before RAS DRAM internal
> refreshing.
> > The DRAMs keep their own internal counter
> > for this. Just swap RAS for CAS,
> > only during HSync and/or VSync.
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John R. Hogerhuis | 1 Jul 2005 22:32
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Re: Rainbow Magazine Article/Program List

On Fri, 2005-07-01 at 13:57 -0600, Michael Wayne Harwood wrote:
> I am looking for a comprehensive article/program list for the Rainbow
> magazine.  I have seen references to "Steve McCoy's" site, but it looks like
> it is defunct.  I can scan, OCR, and proof-read articles lists from the
> magazines themselves in necessary, but I thought it might be nice not to
> have to.  
> 
> Can anyone help?
> 
> Regards,
> Michael Harwood
> 
> 

I think Rainbow magazine back issue volumes were sold in binders. IIRC,
there was also an index to go with them.

Also it's possible that indexes were printed in Rainbow (aside from
TOC), but I don't recall. Maybe in anniversary (I think July) issues?

At least with actual indexes you could avoid having to cull them out of
every TOC from each issue after the OCR is done.

-- John.

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RJRTTY | 2 Jul 2005 02:58
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ebay item

Hey guys check this out.....

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5214878463

what is this thing anyway?

Roy

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Frank Pittel | 2 Jul 2005 03:22

Re: ebay item


As the auction states. It's an emulator pod. When attached to 
a computer with the proper software it will allow you to emulate
a 6809 cpu. The pod is plugged into the hardware that is being debugged.

It helps with software and hardware development.

Frank

On Fri, Jul 01, 2005 at 08:58:24PM -0400, RJRTTY@... wrote:
> Hey guys check this out.....
> 
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5214878463
> 
> 
> what is this thing anyway?
> 
> Roy
> 
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Neil Morrison | 2 Jul 2005 03:39

Re: ebay item


Half a development system for computers.

Neil

----- Original Message ----- 
From: <RJRTTY@...>

> Hey guys check this out.....
> 
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5214878463
> 
> 
> what is this thing anyway?
> 
> Roy

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