The HP Portable Plus computer ROM Drawer uses 28 pin 1MBit (128K) Mask ROMs (TC531000) or 512KBit EPROMs (27C512). A few years ago a company called Personalized Software made something called a ROMBO. This was an adapter that allowed the use of a 32 Pin 27C010 Quad Pack and plugged into the 28 pin socket on the ROM Drawer. The down side of this was that the ROMBO needed a special EPROM programmer to program. Here is a link to a picture of the ROMBO. These are no longer available.

No Will, those datasheets are not listing the pinout of the PG84 version. ..but in the Meantime I've found an Datasheet that lists it, put it on my Webspace: https://www.tiffe.de/htdocs/other/IDT49C402.pdf

At first any Macroassembler should do the job for coding the bits in the control store, but even AMDASM and friends are laying around somwhere on my disks. I thin the time to talk about "real software" is when the cpu sucessfully adds it's first bytes..

Yes, I know, Real Programmers don't use Pascal... (https://homepages.inf.ed.ac.uk/rni/papers/realprg.html)

You forgot to mention that the front panel must use sim TIL311's ..

Yes I know, but technical problems arent my biggest, the biggest problem is spare time.

Regards, Holm

On 2025-03-07 15:36, Holm Tiffe via cctalk wrote: There is a pretty quiet bitslice mailing list. Are you on it?

ben via cctalk wrote: > On 2025-03-08 8:09 a.m., emanuel stiebler via cctalk wrote: >> On 2025-03-07 15:36, Holm Tiffe via cctalk wrote: >>> Hi all, >>> >>> I'm dreaming to build sometimes my own Bit Slice CPU (when I have >>> spare time) >>> and I have collected several IC's in the last years for this purpose.

Ok, this is a full fledged mainframe CPU.. not really what I want todo first. That stuff tends to "explode" in sight of parts, needed power and space, I know that. On the other side I saw different controllers for PDP11/VAX stuff that used the 290x to control "hardware". That are microprogrammed computers w/o any system bus and macro-instructions. Even the controller of an DEC RX01 RX02 is build around two AM2901. (I'm a former east german from "behind the iron curtain" and I own something like a russian PDP11/23 clone, an "Elektronika E60" that was used from a east german company "Carl Zeiss Jena" which had an dependance in my hometown to steer an X-Ray Spectrometer. The russian dual 8" floppy drive has also 2 pcs. of K1084BC1 .. AM2901) My first idea is to build a digital clock with a single 2901 - only micro programmed. Ok, it's total nonsense.. but all what we do here is playing with some outdated stuff, so where this clock.. I hope that I could do this with an single 2901 RALU, that means I have to calculate twice for 8 Bits, like the ALU in a Z80... 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.

> 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

Jon Elson via cctalk wrote: [..] WS59032 multiply ...and you can expand the Registers externally with AM29705 (AM29707) running, I store from 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.. :-) ) higher 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..) project. 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 info(a)tsht.de Tel +49 37292 709778 Mobil: 0172 8790 741

...and you can expand the Registers externally with AM29705 (AM29707)

On Mar 13, 2025, at 3:28 PM, ben via cctalk <cctalk(a)classiccmp.org> wrote: On 2025-03-13 12:24 p.m., Martin Bishop via cctalk wrote: When it works. I see lots low cost Chinese FPGA cards, so that is valid option. They goofed on that, 3 volt transistor logic is negative. :)

On Mar 13, 2025, at 4:35 PM, ben via cctalk <cctalk(a)classiccmp.org> wrote: On 2025-03-13 1:36 p.m., Paul Koning via cctalk wrote: I was thinking of the PDP-8 there. 0 Volts logic 1 -3 volts logic 0. What would the purpose of said computer be? Might be better off with a clean 64 bit design and 16 bit bitslices.

An additional comment on that. To understand any field well, it is generally helpful, and at times crucial, to have some knowledge of early work. I just read a translation of some of the works of Galileo that makes that point in so many words in the introduction. Similarly, while people don't build compilers today the way they did in 1960, it is still valuable to read how Dijkstra and Zonneveld wrote the first ALGOL-60 compiler and, along the way, had to invent many of the compiler construction techniques that were later routinely taught and used in university compiler construction courses. There's an outstanding analysis of that, in the Ph.D. thesis of Gauthier van den Hove. (It's not yet a published document; I think that has something to do with copyright and publication practices at some universities, perhaps Dutch or European conventions.) He subtitled his thesis "New insights from old programs".

paul

I can think of several places where DEC used 2901 designs. One is the VAX 730. One of the PostScript laser printers also used these, I think -- LPS20 perhaps? Not the LPS40, that was a microVAX running VaxELAN based firmware.

Another, and an interesting one, is the UDA50. It has a 16 bit engine using 4 2901s plus a 2910 sequencer. My mentor Anton Chernoff worked on the microcode for it and showed me some of it. I remember it had a specialized assembler where the ALU opcode (for the 2901) was in the left half of the line, and the sequencer opcode (for the 2910) in the right half, separated by a semicolon. The 2901 had condition codes, which were transferred to the 2910 for conditional branches, but with a one cycle delay at least in the UDA50. So you could see weird stuff like this: clr r1 ; bne foo because the conditional branch would act on the condition codes set by the preceding line's ALU part. The UDA50 had an implementation, in a tiny amount of microcode, for a small 16-bit microprocessor instruction set. I think it was roughly a very much simplified PDP-11. That was used for various downloadable diagnostics and service tools, like a disk formatter. Richie Lary of PDP-8 fame wrote that part of the microcode. paul