ISTR that some time ago I read mention here about an EPROM fast enough to approach PROM speeds; anyone share that recollection, or even have a source/part no.?
On Thu, Mar 13, 2025 at 12:47 PM Holm Tiffe via cctalk < cctalk@classiccmp.org> wrote: > Jon Elson via cctalk wrote: > > [..] > > > > > > Later I could try to build something with the 49C402, AM29116 or > WS59032 > > > to save PCB space.. All that stuff is already in my stash of parts, > > > besides many 2901,2903,2909,11,10 etc... > > > Maybe I'm trying to get that PCB with the four AM29203 and AM2910 from > > > GE to life first. > > > > > The 2903 was a VERY nice bit slice chip, it could do single-cycle > multiply > > and divide, as it had an extra shift register for the multiplier bits. > > ...and you can expand the Registers externally with AM29705 (AM29707) > > > The > > 29203 is pin compatible, but faster. Once I got the whole system > running, I > > planned to upgrade to the 29203. I had planned to make device controllers > > with 4 74S181s and a dual-port ram chip for registers, and the control > store > > would be 27C32 EPROMs of the fastest grade. I was hoping to get 4 MIPS > from > > these. > The 49C402 has an expanded Register set (64 words instead of 16), an double > set of ALU Commands. Don't know if it is the same as on the 2903/203. It > contains > the carry readahed circuity too and is 60% faster IDT says... > > The 27C32 would be the bottleneck. I've bought some used AM27C291 in the > past (and compatible Parts from Cypress and TI). > I've pesteres the german company Conitec to implement device support for > those for ther GALEP Devices. Send 10 chips to them and got a Mail later > that they would need more..they where noe all defective now... > The Read Support was added for the GALEP III and IV ..but I'm would'nt > pay additionally and finally build a prommer fort those differential > Eproms myself. I'ts working and no Chip hat to die for it... > > But even with those Eproms (25..55ns) it would be impractical to build > an control store for a single experimental device out of it. I've build > an control store out of old cache RAMs (8kx8). (A friend of mine collected > many of them for me..out of old 486 Mainboards) An Atmega16 with an 4Mbit > Atmel Dataflash could store the Microcode and load it in the WCS. > There are still some Pipeline Registers to solder in and finally to write > the Software for the AVR. ..it's laying around for years now. :-| > > This all was before I knew about IDT71502 WCS Chips that include serial > shift registers.. > We had an Company here in Germany that sold used chips from recycled pcbs > one..the new management endet this. But before it ended I've bought a > bunch of them, besides things like J11, Bus drivers AM29828 and much > other things for a very small amount of bucks. > (From the point I've told them that I wanted the chips to build something > out of > it and I'm not interrested to only look at nice gold ceramic Chips w/o > any scratches..it seems that they send me the best looking Ic's they > had.. :-) ) > > > > > Of course, now this could all be built on a few FPGAs, and get vastly > higher > > performance. > > That's the point where the fun ends..at least for me. Yes, I've done > some designs on Altera CPLDs (schematic entry only), bought a book about > Verilog and one about VHDL .. but spare time is low... > > I don't even want to build a "fast" computer ...nice if it's fast, but > it isn't necessary. > I'm sitting on a PC with an Ryzen 5-3600 and 64Gbyte RAM (no, no Flash > disk, but a RAID arry of fast SAS "spinning rust" disks..) > > > > Yes, a small peripheral controller would be a much more practical > project. > > > > Jon > > Exactly. > First is to get something running.. > > In the old AM29xx Docs (Donnamaye E. White) are even "controllers" > described that don't use any ALU at all, but an AM2910 only. > As long you don't have to shuffle some data, this will be sufficient.. > (Coffee machine?) > > Regards, > Holm > > -- > Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe, > Goethestrasse 15, 09569 Oederan, USt-Id: DE253710583 > i...@tsht.de Tel +49 37292 709778 Mobil: 0172 8790 741 > >
