VOGONS


Reply 1220 of 1229, by pshipkov

User metadata
Rank l33t
Rank
l33t

That is unfortunate indeed. Lets see if 4036yb handles it better for you.
Not surprised that aha-1522b did better than 1542c#.
Once you get the Advansys / SIIG controller, it should move the needle quite a bit.

Btw, i never sa 1522b, only 1520b. Do you really have 22 ?

retro bits and bytes

Reply 1221 of 1229, by MikeSG

User metadata
Rank Member
Rank
Member
pshipkov wrote on 2024-05-19, 05:20:

@MikeSG
What was the point of the flexible ribbon mod ?


I'm simplifying the flush circuit on my design using the Improve Tech circuit. Just missing a few connections.

Will share the gerber files after testing.

Post is at Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Attachments

Last edited by MikeSG on 2024-05-21, 15:26. Edited 2 times in total.

Reply 1222 of 1229, by feipoa

User metadata
Rank l33t++
Rank
l33t++
pshipkov wrote on 2024-05-20, 06:18:
That is unfortunate indeed. Lets see if 4036yb handles it better for you. Not surprised that aha-1522b did better than 1542c#. O […]
Show full quote

That is unfortunate indeed. Lets see if 4036yb handles it better for you.
Not surprised that aha-1522b did better than 1542c#.
Once you get the Advansys / SIIG controller, it should move the needle quite a bit.

Btw, i never sa 1522b, only 1520b. Do you really have 22 ?

Yes, i actually have the AHA-1522B, which just means it contains the integrated floppy port and related IC's. This saves an ISA slot, assuming you use floppy. If you need a multi-I/O card anyway, then it wouldn't help much.

Edit: Attached photo of the 1522B on testbed:

MS-3131_with_AHA-1522B.JPG
Filename
MS-3131_with_AHA-1522B.JPG
File size
1.39 MiB
Views
107 views
File license
CC-BY-4.0
Last edited by feipoa on 2024-05-25, 09:44. Edited 1 time in total.

Plan your life wisely, you'll be dead before you know it.

Reply 1223 of 1229, by pshipkov

User metadata
Rank l33t
Rank
l33t

@MikeSG
I guess you are doing this in the name of completeness, correct ?
I tested these SXL2 CPUs on a LOT of motherboards and with one exception they worked just fine. Not sure if additional improvements are actually needed.
If i don't solder the two chips on the adapter will it still function ?
My point is that simplicity is a positive factor for DIY hobby contraptions given the limited time we can allocate to this stuff.

@Feipoa
Good point that most 386 mobos require multi-i/o card, so 1522 does not bring a lot of value over 1520.

retro bits and bytes

Reply 1224 of 1229, by feipoa

User metadata
Rank l33t++
Rank
l33t++
pshipkov wrote on 2024-05-21, 05:59:
I guess you are doing this in the name of completeness, correct ? I tested these SXL2 CPUs on a LOT of motherboards and with one […]
Show full quote

I guess you are doing this in the name of completeness, correct ?
I tested these SXL2 CPUs on a LOT of motherboards and with one exception they worked just fine. Not sure if additional improvements are actually needed.
If i don't solder the two chips on the adapter will it still function ?
My point is that simplicity is a positive factor for DIY hobby contraptions given the limited time we can allocate to this stuff.

I had the same thinking in this regard. I hope Mike makes the invalidation circuit disable-able with a jumper, or minimally a solder bridge. I haven't run into any 386 boards which didn't work with the SXL2 out of the box with the cyrix.exe utility. Do you recall the exact motherboard you tested which didn't work with the SXL2 and cyrix.exe.

Nonetheless, I think there could be some obscure OEM or MCA systems out there that may benefit from this external cache invalidation circuit, whereby MEMW# and/or cyrix.exe won't cut it. There was another user in this thread who had an MCA system and needed to add an inverter and OR gate to the design to get the SXL2 working, however this option was already added to Alpha 1.

Or maybe with the Improve-It invalidation scheme, we can bypass cyrix.exe all together, or get improved AHA-1542 support? And hopefully without sacrificing overclock-ability. I know I tested for this in the past with a similar Improve-It interposer, but no longer recall the outcome.

pshipkov wrote on 2024-05-21, 05:59:

@Feipoa
Good point that most 386 mobos require multi-i/o card, so 1522 does not bring a lot of value over 1520.

However, for all my systems, I use PS/2 for the mouse, thus skipping the multi-I/O card entirely. You can probably see why the 1522B and 1542CP w/bulit-in floppy appealed to me. If there's ISA slots left, I may still add a serial I/O card to test serial mice if needed.

Plan your life wisely, you'll be dead before you know it.

Reply 1225 of 1229, by MikeSG

User metadata
Rank Member
Rank
Member
pshipkov wrote on 2024-05-21, 05:59:
@MikeSG I guess you are doing this in the name of completeness, correct ? I tested these SXL2 CPUs on a LOT of motherboards and […]
Show full quote

@MikeSG
I guess you are doing this in the name of completeness, correct ?
I tested these SXL2 CPUs on a LOT of motherboards and with one exception they worked just fine. Not sure if additional improvements are actually needed.
If i don't solder the two chips on the adapter will it still function ?
My point is that simplicity is a positive factor for DIY hobby contraptions given the limited time we can allocate to this stuff.

It's mostly for completeness. It's a "wire free" cache invalidation in case the Cyrix utility doesn't work, but I guess it works 99.9% of cases anyway.

I'll just delete the extra chips.

Reply 1226 of 1229, by feipoa

User metadata
Rank l33t++
Rank
l33t++

The extra cache invalidation circuit may also be useful if the user is wanting to run a non DOS-based operating system which cannot run the cyrix.exe utility, like Windows NT, OS/2, or CP/M. I'm not sure if CP/M and OS/2 can run cyrix.exe)

Plan your life wisely, you'll be dead before you know it.

Reply 1227 of 1229, by RayeR

User metadata
Rank Oldbie
Rank
Oldbie

BTW other OSes can be usually booted from plain DOS via GRUB4DOS, so you can configure your HW with DOS utils, call GRUB4DOS.EXE and chainload other OS like NT. It can be all automated in autoexec.bat and grub menu.lst to select some boot item within a given timeout.

Gigabyte GA-P67-DS3-B3, Core i7-2600K @4,5GHz, 8GB DDR3, 128GB SSD, GTX970(GF7900GT), SB Audigy + YMF724F + DreamBlaster combo + LPC2ISA

Reply 1228 of 1229, by feipoa

User metadata
Rank l33t++
Rank
l33t++
RayeR wrote on 2024-05-21, 20:11:

BTW other OSes can be usually booted from plain DOS via GRUB4DOS, so you can configure your HW with DOS utils, call GRUB4DOS.EXE and chainload other OS like NT. It can be all automated in autoexec.bat and grub menu.lst to select some boot item within a given timeout.

This is what I do, but not everyone wants to put in this extra effort.

Plan your life wisely, you'll be dead before you know it.

Reply 1229 of 1229, by MikeSG

User metadata
Rank Member
Rank
Member

Updated my post containing PCB design req, Bill of Materials with the new simpler layout. Re: Custom interposer module for TI486SXL2-66 PGA168 to PGA132 - HELP!

Ordered them today and will arrive between Jun 20 - 30 to test. Once it works I'll upload the gerber files.

Only doubts are whether the press-fit holes are within tolerance. There was an option when ordering to ensure +/- 0.05mm but was +$280AUD.