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Thread: DECtape TC01 vs TC08: Differences?

  1. #1

    Default DECtape TC01 vs TC08: Differences?

    Hi all,

    I'm implementing a few peripherals for my PDP-8 project. I started with the TC08 DECtape controller and wondered how it is different from the TC01. The Small Computer Handbook only states "The TC08 is very much like the TC01".

    Before diving deep into the manuals, does anyone know the differences between the two controllers?

    Regards
    Folke

  2. #2

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    In short. TC01 = transistors ( 0 and -3V logic levels). TC08 = TTL.

  3. #3

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    Ah, so it's just a newer generation without additional features? Sounds like the TC08 is more fitting for a PDP-8/I then, thanks!

  4. #4
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    Quote Originally Posted by fpw View Post
    Sounds like the TC08 is more fitting for a PDP-8/I then, thanks!
    The 8/I at the RICM has a negative I/O bus and a TC01 DECtape controller. This is a very early 8/I, so the TC08 may not have been available.
    Later you could order an 8/I with a positive I/O bus and TC08 DECtape controller.
    You could also use a DW08A to convert the positive bus of an 8/I to the negative bus of an TC01, or use a DW08B to convert the negative bus of an 8/I to a TC08.
    Just to make it more interesting, there is a DW8E that converts the positive bus of an 8/I to Omnibus and theoretically to a TD8E DECtape controller.
    Member of the Rhode Island Computer Museum
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  5. #5

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    Quote Originally Posted by m_thompson View Post
    Just to make it more interesting, there is a DW8E that converts the positive bus of an 8/I to Omnibus and theoretically to a TD8E DECtape controller.
    I think there are driver/timing issues with this last. TD8E timing is tight, the driver is large, and I believe the driver uses 8/E-isms to meet the constraints.

    Vince

  6. #6

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    I thought Folke is making a soc implementaion for his pdp8 project?
    No real Dec stuff involved. Or did I miss something?
    WTB: Case for Altair 8800 ...... Rolands Github projects

  7. #7

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    Quote Originally Posted by Roland Huisman View Post
    I thought Folke is making a soc implementaion for his pdp8 project?
    No real Dec stuff involved. Or did I miss something?
    That's correct, but since the posibus and data break interfaces are implemented exactly as on a real PDP-8/I including proper timing, I want to make sure to pick a realistic set of peripherals before implementing them. In theory, it should even be possible to connect a real peripheral to the SoC system and use it - or to use a real PDP-8/I and connect a simulated peripheral to it. So far, I've decided to start with the following set of peripherals: ASR-33, PC04, TC08, RF08.

    The user will be able to create virtual cabinets and put the peripherals into them to create a nice graphic representation of the whole system with rotating TU55s and blinking TC08s... at least that's the vision.

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