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Thread: A guy walks into a bar...

  1. #1
    Join Date
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    Default A guy walks into a bar...

    ... and says "Anybody got any information on the Everx EV-125 Multi-IO Card?" Or might as well have, 'cuz he'll get the same amount of information as if searching the Internet. ***

    I know this topic has arisen here several times before, but I just want to post what I have learned and ask a few relevant questions:

    In another thread I described the troubles I had trying to sort out the source of parity errors occurring on my 5170. After attempts at configuring an AST RAMPAGE 286 I removed, cleaned, replaced, retested - nada.

    Back to the drawing board I dug out an Everex EV-125 which has COM x 2, LPT and game ports in addition to room for four banks of RAM. Documentation everywhere is the same as what is on STASON.ORG https://stason.org/TULARC/pc/io-card...rd-EV-125.html, which is pretty terse. The card has a forest of jumpers and most are unexplained. The ones that ARE indicated are somewhat confusing, so there was a lot of trial and error. Here is what worked for me on a 512KB AT:

    Base memory selection: Jumper block W3; pins 2:3, 4:5 ALSO jumper block W1, position 6, open - indicating 512k on board
    Added memory configuration: Jumper block W1; pos. 1 OFF, 2 ON, 3 ON, 4 ON, 5 ON - indicating 2 MB (four banks of 18 ICs) **
    Existing memory configuration: DIP Switch block SW1; pos 1 ON, 2 ON, 3 ON, 4 OFF - indicating 0-1 MB
    Extended memory fraction selection: DIP Switch block SW1; pos 5 ON, 6 ON, 7 ON - indicating 0KB extended memory
    Base memory backfill: DIP Switch SW1; pos 8 ON - indicating backfill to 640 from 512

    The remaining jumpers mentioned in STASON were configured the same on my board.

    With these settings I was able to boot and use the system without generating parity errors. By setting W3 correctly and enabling SW1/8 my (AMI) BIOS recognized 639K base memory and 1536K as extended. I do not have any memory managers loaded, but MSD recognizes this configuration as well.

    I do not have any Everex software for the board and I don't know what the other jumpers on the board do. There may be an address conflict with one or more of the ports as well, but I haven't gotten that far. If necessary I can change the addresses and IRQs of the SIIG drive controller.

    ** Now for the question: The STASON docs refer to banks of memory as populated with 4464. My board has 41256s. The only way this would work, that I can see, is if the 4164 are 64x4 and the 41256 are 256x1. Is that what's going on?

    *** Offering a reward for a copy of the original Everex EV-125 documentation.

    HTH

    -CH-

  2. #2

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    Quote Originally Posted by clh333 View Post
    ** Now for the question: The STASON docs refer to banks of memory as populated with 4464. My board has 41256s. The only way this would work, that I can see, is if the 4164 are 64x4 and the 41256 are 256x1. Is that what's going on?
    Sorry, but you can't make up your own facts as you go along.

    4164 = 64x1
    4464 = 64x4
    PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

  3. #3
    Join Date
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    Default

    Point taken: 4464. Excuuuuuse me!

    Got a manual?

    -CH-

  4. #4
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    Default

    Considering the card seems to have four banks of 18 chips I think it's highly unlikely Statson is correct about the card accommodating 4464s. I've seen cases where a pair of 4 bit wide chips like 4464s and 44256s were combined with a single 4164/41256 to get the standard 9-bit Parity RAM banks that PCs expect, but it'd be *weird* to build a RAM bank out of 8x 4464s and a single 41256 doing parity for all four "sub-banks".
    My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs

  5. #5
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    Default

    After more experimentation I have confirmed that the EV-125 in the STASON configuration has serial ports A and B (external) addressed as COM1 (3F8h) and COM2 (2F8h) and that they were active, although masked by the SIIG ports which were configured the same. I moved the SIIG ports to COM3 and COM4 and now each is recognized; I was able to install the MS serial mouse on COM1, for example.

    I tried running the Everex EV-158A software to install an EMM but was unsuccessful. Either I'm not using the correct syntax or there is a software incompatibility. So far the only contribution of the EV-125 is to bring base memory to 640.

    I have not examined the parallel port yet.

    -CH-

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