CPU Shack: RCA CDP1855 COSMAC Multiplier

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CPUShack



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PostPosted: Sat Feb 13, 2016 8:55 pm    Post subject: CPU Shack: RCA CDP1855 COSMAC Multiplier Reply with quote

aberco gave me one of these chips so figured I needed to write an article

http://www.cpushack.com/2016/02/13/rca-cdp1855-a-multiplier-for-the-cosmac/

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Vegeta



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PostPosted: Sun Feb 14, 2016 12:28 am    Post subject: Reply with quote

Informative article, thanks!
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frag_



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PostPosted: Mon Feb 15, 2016 7:24 am    Post subject: Reply with quote

Good to know!
Soviet ones was faster, 2.0 (588BP2) and 0.7us (588BP2A) for 16x16 multiplication at most.
Short datasheet can be found here:
http://www.eandc.ru/upload/iblock/ee3/ee3657b708825dd6ba3a03a7ed2421e6.pdf
Were produced starting early 80s.


Last edited by frag_ on Mon Feb 15, 2016 6:08 pm; edited 1 time in total
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yy2013



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PostPosted: Mon Feb 15, 2016 8:00 am    Post subject: Reply with quote

Nice article! Thank you.
Also the datasheet of 588BP2 by frag_ was useful information for me.
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CPUShack



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PostPosted: Mon Feb 15, 2016 5:09 pm    Post subject: Reply with quote

frag_ wrote:
Good to know!
Soviet ones was faster, 2.0 (588BP2) and 0.7us (588BR2A) for 8x8 multiplication at most.
Short datasheet can be found here:
http://www.eandc.ru/upload/iblock/ee3/ee3657b708825dd6ba3a03a7ed2421e6.pdf
Were produced starting early 80s.


Looking at the datasheet, the Soviet one is like the CDP1855 only by the fact it could do 8x8 multiplication, other then that, its different (no division, no cascading, not set up to work with a 1802 etc)

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frag_



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PostPosted: Mon Feb 15, 2016 6:06 pm    Post subject: Reply with quote

Well, yes, I read it and it's very different multiplier.
And it's 16x16 Very Happy
But at least it has cool rad-hardened version - 1824BP21
http://www.155la3.ru/k1824.htm
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Vegeta



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PostPosted: Tue Feb 16, 2016 12:57 am    Post subject: Reply with quote

So this is not an analogue of the CDP1855? I apologize for the mystification. I did not have the datasheet. I used the online guides. http://madelectronics.ru/book/ims/2009-07-15-20-55-53-423.htm etc.
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CPUShack



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PostPosted: Tue Feb 16, 2016 3:09 am    Post subject: Reply with quote

Vegeta wrote:
So this is not an analogue of the CDP1855? I apologize for the mystification. I did not have the datasheet. I used the online guides. http://madelectronics.ru/book/ims/2009-07-15-20-55-53-423.htm etc.


Correct, though as I mentioned, they may have called it an analog to the 1855 purely to justify making it, but it certainly bares little resemblance.

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