• Transwarp behaviour with ROMX

    From Andrew Roughan@21:1/5 to All on Wed Sep 1 06:02:12 2021
    The Transwarp manual says:

    The only way to activate TransWarp is by powering-up, or "cold-booting",
    the computer.

    Accesses to the Apple's RAM and ROM are restricted to the Apple's clock
    rate of
    1 MHz; therefore, on power-up, TransWarp loads the Apple's ROM into its
    RAM,

    Writing a three (to $C074) will disable the TransWarp card completely and
    pass processing control to the Apple's processor until the TransWarp is
    again activated by cold-booting the system.
    —-

    This combination of behaviour makes coexistence with ROMX difficult.
    Transwarp will shadow ROMX bank 0 at startup and then any attempt by ROMX
    to change ROM is not actioned by TW.

    If the TW is disabled to allow ROMX to function, can’t return to fast
    speed.

    Is there a way to force TW to update its ROM shadow copy?
    E.g. Is there a way to force TW to think it has been cold booted without
    also making ROMX think it has been cold booted?
    Potentially a hardware switch.

    Alternatively, can a new TW firmware help?
    The firmware disassembly shows $1000 org which must be an internal address space. There is no slot firmware visible when the TW is disabled.
    Potentially a different firmware could be written to allow ROMX to do its
    thing and then invoke shadow copy. Not sure if this is feasible.

    Any other ideas?
    Any input in the above?

    Thanks
    Andrew

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