-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I see there's at least a couple DP8421AV-20 up on ebay: http://www.ebay.com/itm/DP8421AV-20-Manu-NS-Encapsulation-PLCC-68-microCMOS-Programmable-256k-1M-4M-/120921409478?pt=LH_DefaultDomain_0&hash=item1c277a47c6#ht_2311wt_819 http://www.ebay.com/itm/DP8421AV-Integrated-Circuit-x-1-pieces-/400308222341?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item5d343ab985#ht_4722wt_1202 http://www.ebay.com/itm/DP8421AV-20-Integrated-Circuit-x-1-pieces-/160838807571?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item2572bd7013#ht_4722wt_1202 Looks like you would need one of those for each 16MB of DRAM if I'm not mistaken. It's a PLCC backage, so that's kind of nice. Even though they are obsolete, they seem to be still available here and there. There is also the DP8422A that can drive 64MB apparently, but it seems to be a little more hard to find. Datasheet attached. - --Mike On 07/15/2012 05:00 PM, John Monahan wrote: > That's a bummer Terry! The problem with static RAM chips like the > 2MX16 is that they take up a lot of board space. With say 8 on an > S-100 board we are still only at 16MG. What I liked about the > Cypress SIMMs is you could fit a lot on a board. I wonder if there > are other Static SIMMs out there still available. > > > > As to the S-100 access, here is my thinking currently.. > > Of the two board 80386 set (CPU & RAM), the CPU board would be made > first and would be self-contained and be able to boot from a > ROM/RAM combination on the S-100 bus. Using cascade counters there > would be a lot of wait states put on the 80386 for both I/O and RAM > access to the S-100 bus. This should not bother the CPU. The > 80386 BS16* line would always be low telling the CPU to expect 16 > bit data, something we already have well working with our 8086 & > 80286 CPU's. > > Up to 16MG of RAM could be used in this way (4 of our 4MG static > RAM boards). > > > > When the above is working the second board would be done. Using a > single 74LS682 we can select what part of the 80386 address range > goes "over the top" via a ribbon cable to a second high density RAM > board. The lower cut off could be 0 to 16MG. Such a board would > run the RAM at a maximum data rate and 32 bits wide. Only data, > address, ALE and R/W lines would be involved. The challenge is to > get as high a density as possible on that board. If I could find > a DRAM controller that would refresh GB's of RAM independently of > the 80386 (putting down wait states when busy), that would be best. > No luck so far. That's why I resorted to the SRAM SIMMs. > > > > As to voltage levels there are a few ways to handle the 3.3V/5V > differences. There are specialized chips for this or you could > perhaps use a resistor/Zener diode as we did on the Lava-10 VGA > board. > > > > Thanks for the suggestion, please keep the discussions going > > > > John > > > > > > > > John Monahan Ph.D > > e-mail: <mailto:mon...@vitasoft.org> mon...@vitasoft.org > > Text: <mailto:mon...@txt.att.net> mon...@txt.att.net > > > > > > From: n8vem...@googlegroups.com > [mailto:n8vem...@googlegroups.com] On Behalf Of Terry Sare Sent: > Sunday, July 15, 2012 10:35 AM To: n8vem...@googlegroups.com > Subject: Re: [N8VEM-S100:951] An 80386 S-100 Board. > > > > Looks like Cypress doesn't make those anymore. > > Searching some distributors best I found in stock was 1M x16 (10ns) > in TSOP1 (12mm x 20mm) package. Rest were BGA (shudder -- not at > home). http://www.issi.com/pdf/61WV102416ALL.pdf Nu Horizons -- > IS61WV102416BLL-10TLI -- INTEGRATED SILICON SOLUTION -- Memory > RoHs $17.1429 Available in Stock Region Order Qty 4031 > North America > > So I am curious -- why do you want to share the memory on the S100 > bus? A 386DX would be seriously throttled running memory through > back plane and the SRAM is ~3.3V (or VDD + 0.2) so you would have > to make sure 5V never gets to any pin. Same thing for 386DX, most > are 5V. Maybe it would be better to consider I/O only version -- > only thing you would not be able to do is DMA from drive > controller. That way the board can run DMA/RAS only refresh and use > standard 100 Pin SODIMM and maybe fit all on one board. This board > is going to be SMT anyway just to get everything to fit and at > least 4 layers IMHO. Fortunately SMT rework stations have come down > in price and you can use a toaster oven to do the reflow work. > There are profiles floating around on the web for that -- I was > doing it on much simpler boards at home a few years back. They just > look kinda toasty if you mess up but they still work:-). > > If you want some way of transferring large blocks of information, > you can implement a dual port memory (or FIFO) that the s100 bus > can see and create a driver on 386 side that treats it like a > communication controller. BTW, You are putting a NIC on this thing, > right? Ah, armchair design is so much easier than doing the real > work:-) > > You can still run MDOS as you get to write the BIOS and Linux may > require some driver modifications. > > ts > > PS: you go to work and see terabyte memory configs, 24+ cores using > 2 procs, 24 plus HDD in single chassis all day and your kinda > forget how far we have come in such a short time till you revisit > the past. > > > On 7/14/2012 8:21 PM, John Monahan wrote: > > Guys I've been looking at the newer Static RAM chips. Some now > come in standard 72 pin SIMMs. > > The 1MX32 and 2MX32 chips from Cypress look like they would go good > with a 80386. See the attached data sheets. There are separate > lines for each 8 bit word so ideal for lines BHE0 - BHE3. Decent > access times too, 12ns. > > > > Next problem finding where I can get them in low numbers! > > > > I have had no look finding a simple DRAM controller that we could > easily use in the Megabyte range. > > > > John > > > > John Monahan Ph.D > > e-mail: mon...@vitasoft.org > > Text: <mailto:mon...@txt.att.net> mon...@txt.att.net > > > > > > From: John Monahan [mailto:mon...@vitasoft.org] Sent: Thursday, > July 12, 2012 7:30 PM To: 'n8vem...@googlegroups.com' Subject: > RE: [N8VEM-S100:939] An 80386 S-100 Board. > > > > So if we used a 16 bit PIC, how would it be setup. Shared RAM > between the 80386 and PIC, sounds even more complicated. Am I > missing something here. > > John > > > > > > From: John Monahan Ph.D > > Chief Scientific Officer > > Synthetic Biologics, Inc. > > Office: (301) 658-6854 > > jmon...@syntheticbiologics.com > > www.syntheticbiologics.com > > NYSE Amex: SYN > > > > From: n8vem...@googlegroups.com > [mailto:n8vem...@googlegroups.com] On Behalf Of Tom Lafleur Sent: > Thursday, July 12, 2012 6:24 PM To: n8vem...@googlegroups.com; > John Monahan Subject: Re: [N8VEM-S100:939] An 80386 S-100 Board. > > > > John... > > here is a tech note on dram controllers... also, today one can get > 70mips, 16bit PIC processor, that might be able to do the job with > very little coding??? cost is $6 > > > > tom... > > On Thu, Jul 12, 2012 at 5:50 PM, John Monahan > <mon...@vitasoft.org> wrote: > > Actually thought of something like that a while back Douglas. I > don't think one could get it to work with the few address lines of > the Z80, besides if we go DRAM may as well go the full hog and get > massive amounts of RAM on the board and high speed. > > > > Was even thinking of some kind of primitive cascade counter, but I > suspect that it would not be that simple, else why are there DRAM > controllers! > > > > John > > > > > > > > From: John Monahan Ph.D > > Chief Scientific Officer > > Synthetic Biologics, Inc. > > Office: (301) 658-6854 <tel:%28301%29%20658-6854> > > jmon...@syntheticbiologics.com > > www.syntheticbiologics.com > > NYSE Amex: SYN > > > > From: n8vem...@googlegroups.com > [mailto:n8vem...@googlegroups.com] On Behalf Of Douglas Goodall > Sent: Thursday, July 12, 2012 5:14 PM To: > n8vem...@googlegroups.com Subject: Re: [N8VEM-S100:936] An 80386 > S-100 Board. > > > > John, > > > > I know it's a silly idea, but the Z-80 has a built in dynamic ram > refresh. > > > > But you would probably want to run the 80386 faster than 20MHz. > > > > Just an idea..... > > > > > > Douglas > > > > > > > > On Jul 12, 2012, at 11:06 AM, John Monahan wrote: > > > > Thanks for excellent suggestions Andrew. I have been reading the > Intel manuals a few times now. I do a lot of plane travel and often > bring it along! Their manuals are excellent. There is a > corresponding software and operating system writers manual as well. > BTW, as well, I found the "The Intel Microprocessors" book by Barry > B. Brey to be outstanding. There are numerous editions. The best I > have is the 7th edition. Easily obtained from Amazon. Recommend > it for anybody using hardware with these chips. Goes all the way up > to Pentium BTW. My only criticism was the 80286 was lightly done. > 80386/80486 <tel:80386%2F80486> much better. > > > > OK back to S-100 board. This is a major undertaking (at least for > me). I have been oscillating between the 80386 or jumping over > right to the 80486. The latter has one big advantage in the it can > accommodate an 8,16 or 32 bit bus dynamically. This for example > means you need only one boot PROM and even old S-100 boards (in > theory) could be used, not that you would normally use the latter > much! However the step from 80286 to 80386 is a bit bigger in > terms of hammering signals into S-100 shape. > > > > There is now doubt we will need two boards. In fact with two boards > there is no reason why the CPU cannot run at its normal max clock > speed with its local memory . Only when we go to the tiny amount or > RAM (relatively speaking) on the S-100 bus would we insert 20-30, > whatever, wait states or slow the CPU clock down dramatically. The > S-100 bus could even be configured possibly as a kind of > reverse/slow RAM cash! > > > > However I'm still stuck with how to dynamically refresh the DRAM > Simms. The problem is that unlike the typical Intel single CPU > examples in our case we have potentially a multiprocessor bus > setup. At times the CPU would be in a dormant/reset state. The > good news is the only shared RAM would other CPU's (a 68K for > example), would be the S-100 Static RAM. > > > > What I would like to find is a circuit that has self-contained DRAM > refresh for 1GB or DRAM (or pseudo-static RAM) circuit. > > > > While on RAM, what is the most dense (commonly available) SMT > static RAM chips people have seen. The best I have seen so far is > 2MX8 IS61WV20488ALL (Jameco #1862446), a long way from 1GB! > > > > Suggestions welcome > > John > > > > > > > > > > From: John Monahan Ph.D > > e-mail: mon...@vitasoft.org > > Text: <mailto:mon...@txt.att.net> mon...@txt.att.net > > > > From: n8vem...@googlegroups.com > [mailto:n8vem...@googlegroups.com] On Behalf Of Andrew Lynch > Sent: Thursday, July 12, 2012 7:16 AM To: > n8vem...@googlegroups.com Subject: RE: [N8VEM-S100:927] An 80386 > S-100 Board. > > > > Hi! Please take a look at this documentation for an S-100 80386DX > board that's capable of running a "sophisticated" operating system > like Linux or NetBSD: > > > > http://bitsavers.org/pdf/intel/_dataBooks/1987_80386_Hardware_Reference_Manu > > al.pdf > > > > I agree the "over the top" daughter board may be necessary for all > the components. I suggest we place all the CPU and bus control > logic on the main CPU board and use a pair of the newer 40 pin (80 > wire) IDE connectors to export all the memory and its interface > logic to another board. > > > > In the Intel 80386 Hardware Reference Manual there are circuits > for interfacing EPROM and DRAM chips. I recommend using the 72 pin > DRAM SIMMs since they are "regular" DRAM chips packed on to mini > circuit boards and use the same interface as a regular DRAM chip. > The key for exporting a memory board will be to have many solid > ground connections between the processor and the memory board so > we'll need to keep them close or just make a double thick S-100 > board using a mezzanine connector like we did on the S-100 System > Monitor Board. If we maximize the full space available it would > give us approximately 100 square inches of PCB space minus the > usual ~10 square inches of S-100 overhead for voltage regulators, > filter capacitors, mezzanine connectors, brackets, mounting holes, > clearance margins, etc. > > > > The main benefit of using the 80386DX is that it meets the minimum > criteria for a "sophisticated" operating system like NetBSD or > Linux which are both essentially SysV/BSD Un*x derivatives/mutants. > AFAIK the minimum requirement is a 32 bit ISA and an MMU with > enough address space to hold a rather large kernel and associated > components. > > > > The memory 16MB addressing limit of the S-100 bus would be possible > in theory to hold Linux or NetBSD but would be extremely limiting > in my opinion unless we were seeking a mini Linux like Freesco. We > should strive for as large a memory space as possible and I believe > 256MB (28 address lines) is a realistic goal using a pair of 128MB > DRAM SIMMs. However, this would require at least 24 true address > lines being multiplexed to DRAM A0-A11 and 8 individual separate > CASx/RASx pairs. To get the density we will need, I think DRAM is > the only realistic option without resorting to hobbyist unfriendly > large SMT devices. Also we can add a pair of 27C1024 16-bit EPROMs > for a full 32 bit data path to the boot ROMs. > > > > This is an enormous project and I recommend starting with a > relatively low CPU speed like 4 MHz as a starting point. Once the > basic hardware is working identify the bottlenecks one at a time > and gradually increase the clock speed. John is well familiar with > this technique since all the CPU boards to date have gone down that > path. > > > > Thanks and have a nice day! > > Andrew Lynch > > > > From: n8vem...@googlegroups.com > [mailto:n8vem...@googlegroups.com] On Behalf Of John Monahan > Sent: Wednesday, July 11, 2012 1:12 AM To: > n8vem...@googlegroups.com Subject: [N8VEM-S100:914] An 80386 > S-100 Board. > > > > Hi guys. Having just finished our 80286 S-100 master/slave S-100 > board, see here:- > > > > http://s100computers.com/My%20System%20Pages/80286%20Board/80286%20CPU%20Boa > > rd.htm > > > > I am thinking how to do the 80386 S-100 board. In a sense it's > easier from a hardware perspective since the jump from 8086 to > 80286 in more than 80286 to 80386. As we know the 80286 is > really just a fast 8086 (and was used as such). > > > > The 80386 really was a new breed and could run some decent > software. That is why I would like to make a new S-100 board. > Since the 80386 has a 16 bit access pin it's easy to have it > address the low RAM on the S-100 bus. It would behave like the > 80286. However to take advantage of the 32 bit data bus and > address lines I'm thinking of having a daughter board with an over > the top connecting cable for all that extra RAM capacity. > > > > The question is; should I use static RAM or DRAM. Static RAM is > easy to interface, but even with SMT chips lower capacity. With > DRAM SIMMS we could have a decent Linux going. > > My question to this group is does anybody have a suggestion for a > good refresh controller chip/circuit. It's particularly tricky > because sometimes the CPU will not have access to the bus and will > be held in its reset state, (Another CPU is running the S-100 > Bus). Alternatively anybody know about "Pseudo Static RAM" chips. > Apparently these are self-contained with their own internal > refresh. Don't know how they are accessed. > > > > Any suggestions/directions... > > John > > > > --- > > Douglas Goodall > > Santa Maria, CA > > www.goodall.com > > > > "Even a blind pig finds a truffle now and then" oink oink!! > > > > > > > > > > > > > > -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJQA0FYAAoJEA7EcEr0emgfQDcIALtdDpRyW1VNxoqKyWaFQaU+ q4n/NvJpFCTklbdNAOiAOjOxr8jlxYw6B+9IB4zJmk8Yce4M9D3J8TgFHunxAEiN CPD6u4Uv291hs2gfP6JTSmrNfD+/DKB/S/t9h1K2VIaI8xNp6LTHPVVJNqUDwc0c y5AnZlAs2AHp30xq4wDVHWKNbioROzhJecMmUfWYawkAi164ZaPiibKUFbZOOs7p 8Gn65OUl4JX0LmGyN+bau9TGOvIP31NZBlBLLWzQUnTmo8s67ow1ugVieH2QkYc2 ATliTQU3o3h8q2GnbJkAub/YoXaMR6OcCjo4dwTrc+Ij6OOcaPXRtIBJ+XwIjHo= =J2xW -----END PGP SIGNATURE-----
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