• MAJ Tom discovers tiny shift lever on "Y" complex

    From Louis Ohland@21:1/5 to All on Sun Sep 4 07:17:37 2022
    https://www.ardent-tool.com/complex/T4_Y.html#Q_vs_Y

    Additionally, a 10-bit bus switch (U76) and a discrete diode (CR4) were
    added to create a level-shifter for the few non-C5C'/C8C' CPU inputs
    signals. This was necessary because the I/O is no longer 5 V-tolerant on
    the P54C CPUs.

    Is that a Hurst shifter? Zero to sixty in how many seconds?

    Drifting video to come?

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  • From Tomas Slavotinek@21:1/5 to Louis Ohland on Sun Sep 4 16:08:54 2022
    On 04.09.2022 14:17, Louis Ohland wrote:
    https://www.ardent-tool.com/complex/T4_Y.html#Q_vs_Y

    Additionally, a 10-bit bus switch (U76) and a discrete diode (CR4) were
    added to create a level-shifter for the few non-C5C'/C8C' CPU inputs
    signals. This was necessary because the I/O is no longer 5 V-tolerant on
    the P54C CPUs.

    Is that a Hurst shifter? Zero to sixty in how many seconds?

    Drifting video to come?

    0-60 in a few hundred picoseconds! Yea, the 3384 is pretty fast. But its drift/skew capabilities are minimal. Which is good thing in this case. ;)

    It surprised me that there were only 10 external CPU input signals
    (ignoring the 5 V clock). The rest is covered by the C5/C8 set as it
    sits between the CPU and the rest of the system (BIU and SynchroStream).
    C5/C8 inputs are 5 V-tolerant and don't need level shifting. And neither
    do any of the CPU/C5/C8 *outputs* of course.

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  • From Louis Ohland@21:1/5 to Tomas Slavotinek on Sun Sep 4 09:25:01 2022
    Anything significant in those ten external signals?

    Tomas Slavotinek wrote:
    10 external CPU input signals

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