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I found an Omniview XL/XE chip...


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#1 DavidMil OFFLINE  

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Posted Fri Aug 11, 2017 10:43 PM

I was back in my attic yesterday and I can across a small container of chips.  Some 6502's, a couple of GTIA's and Pokey chips, several Antic's (older and newer 

versions).  A Freddie, a RIOT chip, some 800 ROM chips, several 6810 chips, a set of 1200 ROM version A chips, and several IBM type chips (8088, 80288,

and math coprocessors).  I found a couple of things I hope someone knows about...  First I found two 6810 chips with all pins soldered together except pin 10 of

the piggybacked chip which is raised and is wired to pin 14 of the lower chip and pin 14 of the upper (piggybacked chip) has been removed.  I 'think' this had

something to do with 810 drives.  Then I found and an Omniview XL/XE EPROM 24 pin chip.  What in the world did this fit into.  The only thing I can think of is a

Ramrod Board, but that would mean it only fits in an 800.  Why the XL/XE?  I'd Appreciate any feedback.

 

Thanks,

DavidMil

Kingwood, Texas  

 



#2 Nezgar OFFLINE  

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Posted Fri Aug 11, 2017 10:53 PM

Omnimon can directly replace the stock ROM chip on XL/XE. The RAMROD board was only a mechanism to switch between 3 different OS ROM's. In my own XE, back in the 90's I made a 4 selectable OS by stacking 4 ROM chips, and wiring in switches to the power pins so I could select which one was 'active'.

 

If you have an XL or XE with a socketed ROM, you can test the chip by popping out the original, and putting that one in.  You'll get 80 column support (hold control-a on powerup or reset) and better 800 OS-B support for Games. I think it reverses the basic select too, so basic is OFF by default unless you hold option on poweron.


Edited by Nezgar, Fri Aug 11, 2017 10:55 PM.


#3 Nezgar OFFLINE  

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Posted Fri Aug 11, 2017 11:13 PM

The stacked 6810's sounds like standard fare for a homebrew USDoubler upgrade for a 1050 to get the 256bytes of RAM needed for double density. (They're 128 bytes each) usually along with an EPROM to replace the stock 1050 ROM.

 

http://www.realdos.n...US Doubler.html



#4 Larry OFFLINE  

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Posted Sat Aug 12, 2017 1:17 AM

Did that Omniview chip have the original label on it? The original CDY logo was distinctive. 24 pins? So if for xl/xe, should be 28? Don't have any chips nearby at the moment... So yes, if it is 24 that is wierd. And afaik, there was no Omniview originally sold that was labeled "xl/xe." There was xl and another one for xe and yet another one for "256".
-Larry

#5 DavidMil OFFLINE  

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Posted Sat Aug 12, 2017 1:18 AM

The stacked 6810's sounds like standard fare for a homebrew USDoubler upgrade for a 1050 to get the 256bytes of RAM needed for double density. (They're 128 bytes each) usually along with an EPROM to replace the stock 1050 ROM.

 

Very similar but not exactly the same.  All the pins on the bottom IC are still there.  All the pins on the top IC are soldered to the lower chip except pins 10 and 14.

Ten is raised and soldered to 14 on the lower chip, and pin 14 on the upper chip has been removed.  But that is really cool info about the US Doubler.  I've saved

it for a future project.

Also, thanks for the info about the Omniview XL/XE.  I'll give it a try Saturday in my 130XE and see what happens.

 

Thanks again,

DavidMil



#6 DavidMil OFFLINE  

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Posted Sat Aug 12, 2017 1:26 AM

Did that Omniview chip have the original label on it? The original CDY logo was distinctive. 24 pins? So if for xl/xe, should be 28? Don't have any chips nearby at the moment... So yes, if it is 24 that is wierd. And afaik, there was no Omniview originally sold that was labeled "xl/xe." There was xl and another one for xe and yet another one for "256".
-Larry

 

The label on the chip says (in black ink):

 

OMNIVIEW

XL/XE   CDY

 

On the left side of the paper there is a large upper case C with a lower case D inside of it and the lower right side of the C also forms a lower case Y.

No date on the paper but the EPROM has a date of 8402 on the bottom.  I also found a Manual for the Omniview XL/XE online.

 

DavidMil


Edited by DavidMil, Sat Aug 12, 2017 1:38 AM.


#7 Larry OFFLINE  

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Posted Sat Aug 12, 2017 1:42 AM

Interesting, and yes, that sounds like the original label. If you try it with expanded memory, see what size ramdisk you get, if any. I'll look through my original Omniview docs a bit later. I have several originals plus some ads from CDY.
-Larry

#8 Nezgar OFFLINE  

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Posted Sat Aug 12, 2017 9:21 AM

Oh I missed that you said the chip was 24 pins not 28. The 1200XL used 2 24 pin OS ROM chips in 28 pin sockets, but XL/XE's used a single 28 pin ROM. Maybe someone else knows better if that is expected to work directly in XL/XE.

Found this which describes the Omniview 256: http://www.atariarch.../05/09/0019.php

Mine is an eprom, and shows "omniview xl" with basic disabled, or typing bye from basic. Not sure if that's the same as OmniView 256? If it includes a ramdisk feature I'm not sure if I've ever seen that, unless maybe my XE Newell 320K ram upgrade was not compatible.

#9 Kyle22 OFFLINE  

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Posted Sat Aug 12, 2017 9:48 AM

The stacked 6810's sounds like standard fare for a homebrew USDoubler upgrade for a 1050 to get the 256bytes of RAM needed for double density. (They're 128 bytes each) usually along with an EPROM to replace the stock 1050 ROM.

 

http://www.realdos.n...US Doubler.html

That link describes an INCORRECT way to make a Doubler.  Here is the correct way: http://atariage.com/...d/#entry2901127



#10 Nezgar OFFLINE  

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Posted Sat Aug 12, 2017 10:30 AM

That link describes an INCORRECT way to make a Doubler.  Here is the correct way: http://atariage.com/...d/#entry2901127

 

Ah right, good catch! I remember reading that before...



#11 DavidMil OFFLINE  

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Posted Wed Aug 16, 2017 12:15 AM

I've looked and looked on the internet and I can't find any info on the installation of this chip.  I can find the user manual but nothing on

installation.  As someone said, this chip will only fit into a 1200XL or an old 800 because it's only 24 pins.

Does anyone have an installation manual for this chip?

 

Thanks,

David



#12 Rybags ONLINE  

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Posted Wed Aug 16, 2017 12:24 AM

"Old 800" - are you sure?   It uses D, E, F Rom chips - 2K and a pair of 4K.  Whether an 8K Rom can be used, no idea.  At the least probably with a cut and jumper wire.

 

Unsure an 800 OS would function very well in an XL - I guess with PORTB set to input mode it's the same as setting output $FF which selects OS and disables Basic (which is irrelevant on stock 1200XL anyway).

 

Installation - for XL it should be nothing other than pull the old and insert the new chip.



#13 DavidMil OFFLINE  

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Posted Thu Aug 17, 2017 10:19 PM

Installation - for XL it should be nothing other than pull the old and insert the new chip.

 

Remember that this chip is only a 24 pin EPROM.  It won't work in a 800XL or 130XE which requires 28 pin OS chips.  That's what has me stumped!

 

David



#14 Rybags ONLINE  

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Posted Thu Aug 17, 2017 10:36 PM

Do 24 pin Eproms even go beyond 4K in size?  Looking up 2764, it's a 28 pin device.



#15 Kyle22 OFFLINE  

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Posted Thu Aug 17, 2017 11:25 PM

I have a BASIC Rev. C cart that I made by removing the original chips in the cart and plugging in a 24 pin 68764 or 68766 EPROM.  Works on the motherboard as well.

 

8K in 24 pins.



#16 1050 OFFLINE  

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Posted Fri Aug 18, 2017 1:26 AM

Correct me if I'm wrong but I remember an A and B
eprom for the 1200XL as in there are two 24 pin jobs
for that one.

#17 DrVenkman ONLINE  

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Posted Fri Aug 18, 2017 6:20 AM

Correct me if I'm wrong but I remember an A and B
eprom for the 1200XL as in there are two 24 pin jobs
for that one.


Some 1200XL’s had two 28-pin EPROMs but many more had two 24-pin ROMs.

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