Why not use 1024 x 1 DIP20 chips (70 or 80 nS) for a total of 2 or 4MB? These chips ar very common and still widely available plus the socket are there.

majestyk wrote on Yesterday, 08:45:

Why not use 1024 x 1 DIP20 chips (70 or 80 nS) for a total of 2 or 4MB? These chips ar very common and still widely available plus the socket are there.

I have no idea, if 1024x1 chips are compatible with this board. I don't even know the board's make - on TRW site it is listed as "unknown 286 Suntac mobo". There is no official user manual available. The closest memory configurations described are in DFI-RACER-286 rev 0 board manual - for memory banks 2 and 3. The originally installed 128 KB DIP-20 DRAM chips I have are 4-bit. The parity chips are 1-bit, but there are none installed on this board.

But first I want to know what's the maximum access time suitable for 16 MHz with WS 0 set for DRAM.

EDITS: Typos + link to pdf added.

For 4 MB you need 36 DIP 20 chips (1024 x 1), 32 for memory + 4 for parity.
Yesterday I successfully tested 80nS memory chips on a slightly overclocked 16MHz 386SX mainboard at 18 MHz with zero WS.

majestyk wrote on Yesterday, 09:13:

Yesterday I successfully tested 80nS memory chips on a slightly overclocked 16MHz 386SX mainboard at 18 MHz with zero WS.

Thanks! 80 ns seems Ok, but what about 100 ns?

I tested with 8MB and interleaving (4 banks). Without interleaving (1 bank, 2MB) I had to set 1 WS.

8 sockets in 2 banks populated with 8 chips, so my 286 mobo DRAM works in interleave mode, right?

But this is not the question here. My problem is with the access time of 120 ns for the originally installed 256x4 DRAM chips, which turned out to be unsuitable for WS 0 at 16 MHz bus. The new working DRAM wait state setting of 1 completely negates the point of my CPU speed upgrade from 12 to 16 MHz 🙁 I need some faster DRAM chips, but these are also hard to find here, so I will get even 100 ns ones (if price is acceptable), if I'm sure, that they are capable to work with WS 0 at 16 MHz.

It seems I phrased my first question in a not so clear way, so I'll correct it.

Have a look into your BIOS settings if interleaving is enabled or not.

Unfortunately this MR BIOS doesn't show such information, even if it is waaaay more sophisticated than the original Award's c*ap.

I still don't get with what this interleave/non-interleave memory configuration could help in my case, since all the available 8 DIP-20 sockets are populated for a total of 1 MB memory. I don't want to remove chips for interleave configuration, since 1 MB RAM is not enough for this 286 system.

I'd better try playing with increasing the RAM refresh cycle time. I think, I have some programs for this, that work with 8086/88 XT-compatible motherboards, but never tried them on any 286 mobo.

Interleave doesn´t affect the usable memory size, it just provides a faster access strategy like reading from two different blocks simultaneously. Still it slacks off access timings so you get away with "slower" RAM.

Besides that not all chipsets are capable of interleaving. I don´t know if this Suntac does. I found no hint in the datasheets so it might be non-interleave by design.
If it doesn´t or BIOS doesn´t you will have to use faster RAM.

majestyk wrote on Yesterday, 10:54:

Interleave doesn´t affect the usable memory size, it just provides a faster access strategy like reading from two different blocks simultaneously. Still it slacks off access timings so you get away with "slower" RAM.

Besides that not all chipsets are capable of interleaving. I don´t know if this Suntac does. I found no hint in the datasheets so it might be non-interleave by design.
If it doesn´t or BIOS doesn´t you will have to use faster RAM.

Ok, probably I misunderstood, that you've depopulated some memory banks to change this RAM interleave modes on your 386 mobo. As I noted, I don't have a single clue, if this Suntac ST62C00x (C008) chipset supports such thing and there's nothing about memory interleaving settings in the MR BIOS I use now, nor in the original Award's BIOS thing.

Thanks for your confirmation, that 80 ns DRAM chips will do the job (I was sure about this), but my first question is - are 100 ns DRAM chips "fast enough" to sustain 16 MHz bus with DRAM wait state set to 0, and I still have no answer.

As I noted, without interleaving - and that´s what we must assume in your case - I was not able to run 80nS @ 18MHz with zero WS - I had to switch to 1WS.
I think I tried 16MHz also and it worked with zero WS. But you can see we are at the edge at this point: Depending on the chipset, the quality, variance, areing and past life of the chips 80nS will probably work; 100 nS might work or not.

I don't need those DRAM (or SRAM) chips to work with WS set to 0 at more than 16 MHz bus. According to some shared user's experience this Suntac chipset is not capable to sustain more than 16 MHz. I don't want to experiment with higher bus frequencies, because even if all the six chips of the chipset get slightly worm, now the AMD N80L286-16/S CPU runs pretty hot - I can't touch it for more than 2-3 seconds and I have no option to install some heatsink with PLCC68 socket. So, 16 MHz is the absolute upper limit for this mobo and the installed CPU.

analog_programmer wrote on Yesterday, 09:15:

majestyk wrote on Yesterday, 09:13:

Yesterday I successfully tested 80nS memory chips on a slightly overclocked 16MHz 386SX mainboard at 18 MHz with zero WS.

Thanks! 80 ns seems Ok, but what about 100 ns?

No

maxtherabbit wrote on Yesterday, 12:59:

analog_programmer wrote on Yesterday, 09:15:

majestyk wrote on Yesterday, 09:13:

Yesterday I successfully tested 80nS memory chips on a slightly overclocked 16MHz 386SX mainboard at 18 MHz with zero WS.

Thanks! 80 ns seems Ok, but what about 100 ns?

No

Thanks! Then I'll look only for 80 ns DRAM or better off SRAM chips.

Do you have an idea, if there are DIP-20 DRAM or SRAM chips with 512x4 or even 1024x4 internal organization? SOJ-package chips also may work with some small PCB per-chip adapters, but such modifications will cost even more time and €.

Here´s the official requirement for the C&T NEAT-SX chipset from the ECS manual:

For non-interleave @ 16 MHz you need 60nS!

This is probably "on the safe side"(same timings as for 20 MHz!) and things could be slightly different for Suntac (don´t think so) and maybe Suntac does provide (hidden) interleave after all?
I wouldn´t bother trying 100nS or 120nS.

majestyk wrote on Yesterday, 13:22:

Here´s the official requirement for the C&T NEAT-SX chipset from the ECS manual: […]
Show full quote

Here´s the official requirement for the C&T NEAT-SX chipset from the ECS manual:

The attachment non_interleave.jpg is no longer available

For non-interleave @ 16 MHz you need 60nS!

This is probably "on the safe side"(same timings as for 20 MHz!) and things could be slightly different for Suntac (don´t think so) and maybe Suntac does provide (hidden) interleave after all?
I wouldn´t bother trying 100nS or 120nS.

Thanks for the info!

So, we assume that this Suntac chipset works only in non-interleave memory mode, and now I need even faster 60 ns DIP-20 DRAM 4-bit chips. "Niiiiice" 😁

Meanwhile I experienced some system hanging and instability, so it seems that even DRAM WS set to 1 doesn't help with the original 120 ns DRAM chips at 16 MHz 🙁

I'm reverting back to 12 MHz with DRAM WS set to 0 + FASTDRAM.COM (a slower DRAM refresh cycles setter for XT-class PCs helps a little for overall system performance increase) 'til I get some 60 ns DIP-20 DRAM 4-bit chips, if such exist.

so we got yours
https://theretroweb.com/motherboards/s/unknown-suntac-286
somewhat similar, but MTL document invents 4 ram banks (there are two real banks, just routed to two sets of sockets) so not exact copy, jumpers match tho
https://theretroweb.com/motherboards/s/dfi-racer-286-rev-0

and finally a winner:
https://theretroweb.com/motherboards/s/panatek-pk-009

has proper manual, all jumpers match, confirms MTL documenting 36x 4411000 (1M X 1) for 4MB
manual doesnt mention interleave

unknown-suntac-286 and panatek-pk-009 maybe should be consolidated into one entry?

panatek-pk-009 manual also shows a drawing of second version matching those four 😀
https://theretroweb.com/motherboards/s/auva-c … aby-286-bam-12s
https://theretroweb.com/motherboards/s/morse-kp-286-12mhz
https://theretroweb.com/motherboards/s/magitronics-b233
https://theretroweb.com/motherboards/s/unknown-js-128a

Those four also maybe should be one entry with names listed under 'Also known as'.

rasz_pl wrote on Yesterday, 23:32:

so we got yours https://theretroweb.com/motherboards/s/unknown-suntac-286 somewhat similar, but MTL document invents 4 ram banks […]
Show full quote

so we got yours
https://theretroweb.com/motherboards/s/unknown-suntac-286
somewhat similar, but MTL document invents 4 ram banks (there are two real banks, just routed to two sets of sockets) so not exact copy, jumpers match tho
https://theretroweb.com/motherboards/s/dfi-racer-286-rev-0

and finally a winner:
https://theretroweb.com/motherboards/s/panatek-pk-009

has proper manual, all jumpers match, confirms MTL documenting 36x 4411000 (1M X 1) for 4MB
manual doesnt mention interleave

unknown-suntac-286 and panatek-pk-009 maybe should be consolidated into one entry?

panatek-pk-009 manual also shows a drawing of second version matching those four 😀
https://theretroweb.com/motherboards/s/auva-c … aby-286-bam-12s
https://theretroweb.com/motherboards/s/morse-kp-286-12mhz
https://theretroweb.com/motherboards/s/magitronics-b233
https://theretroweb.com/motherboards/s/unknown-js-128a

Those four also maybe should be one entry with names listed under 'Also known as'.

Thanks for trying to find the exact motherboard match on TRW, but I have to disappoint you. I already checked (a couple of times) all those boards with the same Suntac ST62C00x (C008) chipset, and nothing matches at 100% to mine.

The Panatek PK-009 motherboard, that you're suggesting as a "matching board", looks like mine, but only visually - there are some minor differences in the circuit and the components located "above" the crystal oscillator. Also Panatek's DSP1 DIP-swithes have same functions, but the separate switches do not match functionally the order of DSP1 Sw1-Sw8 on my unknown board (at least half of them are connected in different way/order) and that's why I made my own "user manual" for my unknown board (you can compare it to Panatek's manual information about the DSP1 switches and you will see the differences, just like I did it again). But I think, the most of jumpers match as locations and functions, but not as a markings. At least in the Panatek's manual there is a description for the jumpers near the keyboard controller (those have to match functionally, since the keyboard controller chip is basically the same).

I could use some of the memory information from the Panatek's manual tho.

The "unknown Suntac board" I pointed as a "match" also visually looks like mine, but there are the same minor differences in the circuit and the components "above" the crystal oscillator - just like with the Panatek's board. So, the "unknown Suntac board" is much closer visually to Panatek PK-009, if not exact match. But we don't know nothing about the DSP1 on the "[Unknown] (Suntac 286)" board nor its jumpers. They could match those on my board or the ones on Panatek's board - who knows?

So, please, do not merge any of these board's articles on TRW site, since we are not sure if the "[Unknown] (Suntac 286)" mobo matches 100% to Panatek PK-099 board. Thank you!

The other four motherboards you listed are visually way different compared to mine, so I didn't look at them in details if they match to each other.

P.S. For sure the crippled Award BIOS 3.03HL is one and the same for all those Suntac ST62C00x (C008) based motherboards, but who needs such a cr*p? Microid Research BIOS 1.65 STD_286 Generic is the best one for these.

analog_programmer wrote on Today, 06:31:

The Panatek PK-009 motherboard, that you're suggesting as a "matching board", looks like mine

Sorry. I assumed unknown-suntac-286 matched your board. Ill admit I didnt look at your picture because its bad quality 😀
imo Panatek PK-009 matches unknown-suntac-286. I resized and distorted images to match size and was flipping between them, the only difference I could spot was guard copper pours around mounting holes.

analog_programmer wrote on Today, 06:31:

, but only visually - there are some minor differences in the circuit and the components located "above" the crystal oscillator.

yours does indeed look different, that circuit might be 0 wairstates implementation, looks similar to whats in panatek manual.

analog_programmer wrote on Today, 06:31:

So, please, do not merge any of these board's articles on TRW site, since we are not sure if the "[Unknown] (Suntac 286)" mobo matches 100% to Panatek PK-099 board.

oh dont worry, I have 0 authority on trw 😀