Re: AT/LANTIC DP83905 broken EPROM

Posted on 2024-02-16, 16:17

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Just make sure to enable the software write protection I mentioned earlier, and avoid non-B 28C64 which lacks this feature. Yes, I've already faced the problem with EEPROM contents corruption. No matter if I set BPWR (DP83905 Control B register bit 6) or not it rewrites random bytes. So write …

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Re: AT/LANTIC DP83905 broken EPROM

Posted on 2024-02-16, 12:13

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Deunan wrote on 2024-02-16, 09:48: Just a quick question, do you mean 28C256 pinout or standard 27256 pinout? Because these two are different and A14 on the EEPROM is on pin 1, which on standard ROM/EPROM is VPP, so would be permanently tied to +5V. I mean AT28C256 @ DIP-28. The card looks too …

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Re: AT/LANTIC DP83905 broken EPROM

Posted on 2024-02-16, 01:37

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Well... I partially figured out the problem. And it is not related to configuration tool but to the card itself. My card is damn slow and refuses to work properly at higher bus frequencies or ROMs I use (AT28C64B and AT28C256) are too slow. That is why it caused checksum errors. Moreover it acts …

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Re: Unknown 486 board?

Posted on 2024-02-15, 13:54

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Is this the one you have [Unknown] VL-BUS 471 VER A2?

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Re: AT/LANTIC DP83905 broken EPROM

Posted on 2024-02-15, 00:45

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I use either 386DX-40 or 486x5-133. Same results except 486 doesn't complain about "Off board checksum" I checked the contents of EEPROM each time ran configuration utility. 0x73 or 0x00 it doesn't seem to matter at least for my card. It uses 8 first bytes to store MAC address and its checksum (my …

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Re: AT/LANTIC DP83905 broken EPROM

Posted on 2024-02-14, 23:20

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

According to Hardware Users' Guide the configuration tool writes wrong values to Config C register. That leads to incorrect mapping of boot ROM to address space and crashes on some old BIOSes. I'm intentionnaly not placing here the config tool to avoid confusing other users.

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Re: AT/LANTIC DP83905 broken EPROM

Posted on 2024-02-14, 21:21

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Nope, EEPROM is alive. I've found docs on this chipset and managed to reconstruct EEPROM content to the level it doesn't complain on "Off board parity error". Will post the dump here as soon as I figure out what was the reason of corrupt config in EEPROM.

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AT/LANTIC DP83905 broken EPROM

Posted on 2024-02-14, 16:46

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I've got network card on National Semiconductor AT/LANTIC DP83905 chip. I configured it with the tool found on the Internet and added 32kB boot ROM at address 0xC800 but it turned into "Offboard checksum error" while booting my 386DX. In a 486 board it can still be configured but same tool reports …

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Re: Dos 6 conventional memory tricks

Posted on 2024-02-12, 12:47

by

by froller

in Marvin \ Software

in Marvin \ Software

I usually include everything and then watch with UMBINFO if it is used by and then exclude.

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Re: Dos 6 conventional memory tricks

Posted on 2024-02-12, 00:41

by

by froller

in Marvin \ Software

in Marvin \ Software

This will help Copy code to clipboard 1 DEVICE=C:\WINDOWS\emm386.exe D=64 I=B000-B7FF I=C800-EFFF FRAME=C800 RAM If you have cards with OPTROM installed then use UMBINFO.COM to determine where their ROMs are located and exclude it from arguments for EMM386.EXE.

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Re: Recommended DOS file manager?

Posted on 2024-02-12, 00:29

by

by froller

in Marvin \ Software

in Marvin \ Software

Before I look into it: does it support multi-tasking? BTW, I want my mother to use the computer as well, but she's not good with computers. :( I asked her if she would use my laptops there, but she said she's afraid of breaking them. :( I have Moo installed on it and set up for minimal use. I can …

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Re: Recommended DOS file manager?

Posted on 2024-02-09, 20:25

by

by froller

in Marvin \ Software

in Marvin \ Software

Jo22 wrote on 2024-02-09, 18:09: More like task swapping, though, maybe. 🤷‍♂️ Cool! Never knew it can do this. Nope, DN can't do such things. It is more like Norton Commander on steroids.

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Re: Native PS/2 mouse implementation for 386/486 boards using the keyboard controller

Posted on 2024-02-09, 16:05

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Tiido wrote on 2024-02-09, 15:52: Those parts only exist there for EMC regulations, they don't serve a functional purpose so to speak. seems true

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Re: Native PS/2 mouse implementation for 386/486 boards using the keyboard controller

Posted on 2024-02-09, 16:02

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Interesting. For the boards I measured the 2-10 uH values for mouse clock and data, it would be interesting to see what these boards are using for keyboard clock and data. I think they were of the same range. Nonetheless, it doesn't seem like the value here matters all that much. When I produce the …

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Re: Recommended DOS file manager?

Posted on 2024-02-09, 15:36

by

by froller

in Marvin \ Software

in Marvin \ Software

I heard that DOSSHELL is also not multi-tasking but task-switching: it will only run one task at a time but can keep multiple apps in memory and allow me to switch between them. Will DOS Navigator do the same? Never heard of DOSSHELL can switch tasks. You might have confused it with DESQview. Last …

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Re: Problem with manually created DOS 6.22 floppy image

Posted on 2024-02-09, 15:11

by

by froller

in Marvin \ Software

in Marvin \ Software

It's not just the proper boot sector. MS-DOS also requires some files to be in the right order on the disk. First put IO.SYS on the disk, then MSDOS.SYS. Third file should be COMMAND.COM, but I'm not sure whether file order is still important with this file. MS-DOS 5.0 boot sector (also used by MS- …

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Re: Recommended DOS file manager?

Posted on 2024-02-09, 14:45

by

by froller

in Marvin \ Software

in Marvin \ Software

I prefer good old DOS Navigator 1.51 as my primary file manager. And I use Volkov Commander 4.99.08 for boot diskettes 'cause it is much smaller. DOS Navigator is TurboVision-based and is capable of switching between windows (disk pannels, editors, viewers, terminals etc.) however it is not true …

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Re: Native PS/2 mouse implementation for 386/486 boards using the keyboard controller

Posted on 2024-02-09, 13:50

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I noticed that the Lucky Star LS-486E rev.D upgrade guide uses 470 uH, which I assume maxtherabbit adopted. It was not clear to me why this value was selected. Is there any benefit in using the higher inductance? If you take a look at datasheet on VT82C42N / HT6542B you'll see the keyboard and …

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Re: What retro activity did you get up to today?

Posted on 2023-12-23, 00:40

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Today I got to nearest post office to pick up 4 of 8x32K and 1 of 1x32K static RAM chips. And I've just installed them into my 386DX-40 board and got 20% performance boost (from 51.5 to 62.4 points in Landmark). Not as cool as hex-editing BIOS images to fix Y2K problem in 2023 but also one step …

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Re: LuckyStar LS-486e Rev:D Hardware Upgrade Guide

Posted on 2023-12-18, 23:35

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

New BIOS images (for original VT82C41N and implanted VT82C42) added. Both Y2K patched.

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