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Chuck(G)

  1. Cloning a HAL/PAL, Part 11

    This example details cloning the Creative Sound Blaster CT1350B U12 PAL. If you're just starting out on this thread, go to the start at Part 1.

    Okay, so we've got a weird looking PAL "brute force" dump, that has 10 inputs and 8 outputs, but it doesn't work. In particular, we've noticed that the data from dumping the dupe doesn't match the original:

    Code:
    000000  A1 A9 B1 BB BB BB BB BB-A1 A9 B1 BB BB BB BB BB
    ...
    008000  A1 A9 B1 BB BB BB BB BB-E1
    ...

    Updated June 12th, 2019 at 11:22 PM by Chuck(G)

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  2. Cloning a HAL/PAL, Part 10

    Part 1 of this series starts here.

    A real-world example--the Sound Blaster CT1350B upgrade PAL (U12 on the board with a label that says 0048013500).

    This is a PAL16L8, with the security fuse blown, so it's a perfect test case. The sample file from the little "brute force" board is SB20.BIN (attached below). Running this through tt16l8, we find that there are 10 inputs and 8 outputs--no big surprise. Taking this output and running it through Minilog, we ...

    Updated June 12th, 2019 at 10:31 PM by Chuck(G)

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  3. Cloning a HAL/PAL, Part 9

    Part 1 of this series is here.

    Picking up where we left off, our little board is now creating 64K binary files for parts, which should allow us to identify inputs and outputs.

    To do this, the program tt16l8 is used (see attached file). This program not only separates inputs from outputs, but also attempts to optimize the truth table down to its smallest size. It can produce output for either Minilog or Espresso and optimization can be disabled.

    Basically, ...

    Updated June 12th, 2019 at 10:32 PM by Chuck(G)

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  4. Cloning a PAL/HAL - Part 8

    Part 1 of this series.

    A very common part is the PAL16L8, a 20-pin device (Datasheet). You'll see this part on vintage gear a lot after about 1988.

    Like the PAL10L8, there are 10 inputs, but there's a twist. Where the PAL10L8 had 8 dedicated outputs, the PAL16L8 allows 6 of these signals to be programmed as inputs or outputs. Thus, we can have 10 inputs and 8 outputs, 11 inputs and 7 outputs,...16 inputs and 2 outputs. You can see that the PAL16L8 can replace a ...

    Updated June 12th, 2019 at 11:15 PM by Chuck(G)

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  5. Cloning a PAL/HAL (Part 7)

    To see Part 6, click here

    To go to Part 1, click here


    Finally, you program the GAL with your programmer. For this one, I used an inexpensive programmer, the Chinese TOP853. These are sold on eBay, and if you're patient, you can pick one up for about $25, shipped. Mine worked right out of the box.

    It's a good idea to erase the GAL before programming, even if it's brand-new. A random sampling shows quite a few with some fuses blown.

    ...

    Updated June 12th, 2019 at 11:12 PM by Chuck(G)

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