RetroBrew Computers Forum: General Discussion » Has anyone reverse engineered SP0256A external serial speech ROM

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Re: Arduino lab tool wrapped-around a SP0256 to reverse engineer an unobtainium SPR000 [message #10746 is a reply to message #10745]

Wed, 01 May 2024 17:09

lynchaj
Messages: 1080
Registered: June 2016

Senior Member

Hi
There is really good information in the SPR016 datasheet which helps explain how the SPR000 *should* work. There is a block diagram showing the information flow. Basically substitute a parallel EPROM (2732) for the internal mask ROM and you're there.

The SP0256B datasheet has some good information on the SP0256 serial ROM command sequences and also timing diagrams.

I think there is enough information to piece together a SPR000 workalike but not enough to reverse engineer the SPR000 itself. Still no pinout information.

I am hoping to purchase or borrow an SFD2000 and use my VOM to ohm out the PCB and using datasheets for the other chips (74LS138, SP0256, 2732) deduce the SPR000 pinout sufficient to make a test board. Maybe that will work but it is dependent on a series of miracles happening. It's a rather dicey proposition at this point.

The timing requirements of the synchronous 1.56 MHz clock pretty much rules out the MCU approach. Maybe a Raspberry Pi Pico coded in assembler might be fast enough -- maybe -- but it also has to be 5V tolerant at least. I think the CPLD approach is probably the highest probability of success but that's no slam dunk either. The information in the SPR016 and SP0256 datasheets is pretty sparse and may be missing important details.

Best of luck! Thanks, Andrew Lynch

PS, the best info I have on the internal guts of the SP0256A-AL2 found here: http://spatula-city.org/~im14u2c/sp0256-al2/

Attachment: SPR016.pdf
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Attachment: SP0256B.pdf
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[Updated on: Wed, 01 May 2024 17:24]

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[Message index]

		Has anyone reverse engineered SP0256A external serial speech ROM By: lynchaj on Wed, 03 April 2024 08:38
		Can the SP-0256A Speech Processor be Reverse Engineered? By: jayindallas on Sat, 06 April 2024 09:26
		Reading G.I. SPRnnn External Serial ROM Content By: jayindallas on Mon, 08 April 2024 10:01
		Re: Method to read a SPR-xxx External Rom \| 2007 Internal Rom Dump \| 2017 SPPR256 by FPGA By: lynchaj on Mon, 08 April 2024 10:34
		Method to read a SPRnnn External Rom with an Arduino By: jayindallas on Mon, 08 April 2024 11:03
		Re: Theoretical Method to read a SPR-xxx External Rom with an Arduino By: lynchaj on Tue, 16 April 2024 11:23
		RPi Pico W wrapped around a SP0250 or SP0256 *Updated 20250202 By: jayindallas on Tue, 16 April 2024 18:27
		Re: RPi Pico W wrapped around a SP0250 or SP0256 By: lynchaj on Wed, 17 April 2024 04:10
		Arduino lab tool wrapped-around a SP0256 to reverse engineer an unobtainium SPR000 By: jayindallas on Wed, 01 May 2024 08:21
		Re: Arduino lab tool wrapped-around a SP0256 to reverse engineer an unobtainium SPR000 By: lynchaj on Wed, 01 May 2024 17:09
		Re: Arduino lab tool wrapped-around a SP0256 to reverse engineer an unobtainium SPR000 By: plasmo on Thu, 02 May 2024 20:45
		Re: Arduino lab tool wrapped-around a SP0256 to reverse engineer an unobtainium SPR000 By: lynchaj on Fri, 03 May 2024 04:17
		Re: Has anyone reverse engineered SP0256A external serial speech ROM By: plasmo on Sun, 12 May 2024 20:46
		Re: Has anyone reverse engineered SP0256A external serial speech ROM By: plasmo on Sun, 12 May 2024 20:51
		Re: Has anyone reverse engineered SP0256A external serial speech ROM By: lynchaj on Mon, 13 May 2024 03:12
		Re: Has anyone reverse engineered SP0256A external serial speech ROM By: plasmo on Mon, 13 May 2024 06:08
		Re: Has anyone reverse engineered SP0256A external serial speech ROM By: lynchaj on Mon, 13 May 2024 09:56
		Re: Has anyone reverse engineered SP0256A external serial speech ROM By: plasmo on Mon, 13 May 2024 20:10
		Re: Has anyone reverse engineered SP0256A external serial speech ROM By: lynchaj on Tue, 14 May 2024 03:17
		Re: Has anyone reverse engineered SP0256A external serial speech ROM By: plasmo on Tue, 14 May 2024 20:07
		Re: Has anyone reverse engineered SP0256A external serial speech ROM By: lynchaj on Wed, 15 May 2024 03:43
		Re: Has anyone reverse engineered SP0256A external serial speech ROM By: plasmo on Thu, 16 May 2024 07:57
		Re: Has anyone reverse engineered SP0256A external serial speech ROM By: lynchaj on Fri, 17 May 2024 04:14
		Re: Has anyone reverse engineered SP0256A external serial speech ROM By: lynchaj on Fri, 17 May 2024 05:29
		Re: Has anyone reverse engineered SP0256A external serial speech ROM By: plasmo on Fri, 17 May 2024 12:06
		Re: Has anyone reverse engineered SP0256A external serial speech ROM By: lynchaj on Fri, 17 May 2024 18:49
		Re: Has anyone reverse engineered SP0256A external serial speech ROM By: plasmo on Fri, 17 May 2024 21:31
		Re: Has anyone reverse engineered SP0256A external serial speech ROM By: lynchaj on Sat, 18 May 2024 03:27
		Re: Has anyone reverse engineered SP0256A external serial speech ROM By: lynchaj on Sat, 18 May 2024 04:29
		Re: Has anyone reverse engineered SP0256A external serial speech ROM By: lynchaj on Sat, 18 May 2024 05:55
		Re: Has anyone reverse engineered SP0256A external serial speech ROM By: berzerkula on Tue, 16 July 2024 00:01

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