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Thread: FreHD on Model II/12/16/16B/6000 - FIRST ATTEMPT

  1. #71

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    Quote Originally Posted by lowen View Post
    Yeah, I see that I already did look into the FreHD code in post #20. So someone needs to write the code for the PIC on FreHD to emulate the IRQ, and make sure it's wired to the correct pin on the interface.
    This is correct. I never could implement the interrupt since I don't have access to a model 2... and nobody could ever provide me with traces taken from a logic analyzer... But there is provision to add the IRQ handler (the GAL has one or two IO pins left). At the same time, it'd be good to fix some output signals which should be open-collector... and maybe use a better microcontroller, but my goal (at that time) was to just hack something quickly, I never thought other people could be interested in this project

    -Fred

  2. #72

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    Quote Originally Posted by veco View Post
    This is correct. I never could implement the interrupt since I don't have access to a model 2... and nobody could ever provide me with traces taken from a logic analyzer... But there is provision to add the IRQ handler (the GAL has one or two IO pins left). At the same time, it'd be good to fix some output signals which should be open-collector... and maybe use a better microcontroller, but my goal (at that time) was to just hack something quickly, I never thought other people could be interested in this project

    -Fred
    A FreHD Mk. 2?

  3. #73
    Join Date
    Feb 2007
    Location
    Metzger, Oregon
    Posts
    113

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    I hate to ask, as I would like a "proper" FreHD for the Model II that works with all OS options, but would it be possible to use the current FreHD without IRQ support under LS-DOS? It sounds like LS-DOS isn't making use of interrupts anyway, and that's all I really intend to use on the Model II at this point. My dilemma is that I don't currently own a FreHD, I would like to get one eventually for the Model I,III, and 4P; but I also own a Model II with no software/media, so it would be perfect if I could share the same FreHD between them all. So do I wait for a new rev that has IRQ support (with no guarantee that would ever happen) or do I buy now and hope that it can some day work with the Model II? If I could format the SD card on the Model 4P and at least make use of it under LS-DOS on the Model II, then it might not be worth the wait for IRQ support, at least for me.

    Also, I understand that some Model IIs don't support hard drive booting, is there any easy way to determine which version I have?

    If IRQ support wasn't needed, could a simpler interface board be used to connect the FreHD to the Model II bus? Would the additional RAM still be needed?

  4. #74

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    Quote Originally Posted by dano View Post
    Also, I understand that some Model IIs don't support hard drive booting, is there any easy way to determine which version I have?
    1. Get the TRS8TEST.IMD from https://github.com/pski/model2archiv...re/Diagnostics
    2. Run MEMII -> Shadow ROM Checksum
    3. See https://github.com/pski/trs-xenix/bl...letin-II33.txt

  5. #75
    Join Date
    Feb 2007
    Location
    Metzger, Oregon
    Posts
    113

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    Thanks Pete,

    I guess I should have been a little more clear though. I currently have no way to boot the Model II. My thinking was that I might be able to avoid having to buy 8" media and either find a way to make my PC write a disk image, or having someone ship me a boot disk, if I could just boot the machine directly off of the FreHD. There was a collector just north of me in Vancouver Washington that has/had a Model 16B or 6000 (can't remember which), maybe I will try to track him down and start there.

    -Dan

  6. #76

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    Another option for booting the Model II is to use a floppy emulator such as a Lotharek HxC. I've booted my Model II and my Model 12 from disk images with one, after hooking it up with an adapter board that I made. The adapter board isn't strictly necessary; you can wire up your own adapter cable if you prefer. I don't sell the adapter board, but it's easy to make your own after ordering bare boards from OSH Park.

  7. #77

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    Quote Originally Posted by NF6X View Post
    Another option for booting the Model II is to use a floppy emulator such as a Lotharek HxC. I've booted my Model II and my Model 12 from disk images with one, after hooking it up with an adapter board that I made. The adapter board isn't strictly necessary; you can wire up your own adapter cable if you prefer. I don't sell the adapter board, but it's easy to make your own after ordering bare boards from OSH Park.
    I've built one of your adapters. It's much easier than making the cable.

  8. #78
    Join Date
    Jan 2011
    Location
    Portland, Oregon
    Posts
    560
    Blog Entries
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    @dano: I have had my MII working with an HxC which doesn't immediately help you. However I'm in NE Portland (vic I-84 & I-205) and have a pile of bootable 8" disks. Do you have any non-booting disks to swap?

    BTW: ATT my MII is in storage providing a "flat spot" to pile other stuff on.

    Mike

  9. #79

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    Also, don't forget about the Model II Archive Project if you need some DOS disks.

    http://pski.net/trs-80-model-ii-archive-project/

  10. #80
    Join Date
    Feb 2007
    Location
    Metzger, Oregon
    Posts
    113

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    The HxC isn't a bad idea, but in a way it takes me back to the same dilemma: If get a FreHD for use with the Model I/III/4, then I would love to use it with the Model II instead of buying another storage device. That said, if all else fails then I could always use a 5.25" drive for the same purpose I suppose. Got lots of those. Either way I am thinking of buying one of the adaptor boards, I think it would look better than anything I could prototype, and it would avoid any unneeded mistakes.

    Mike: I would love to take you up on the offer, I just need to dig trough the disks that came with the computer and see what I have. Everything is stored away as we are in the process of moving. I'll check as soon as I can and then send you a PM.

    Thanks for the link to the Model II archive project, it's nice to see others taking an interest in these machines, when time allows I'll look though my disks and manuals and see if there's anything I can add.

    -Dan

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