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Thread: fun with TI-74s...

  1. #1

    Default fun with TI-74s...

    Default user memory "partition" in a Basicalc is at >4000, aka 0x4000h among the heathen...

    >4000 & up is cartridge memory, >3FFF & below is "System" RAM. 8K Cartridge memory
    can be appended to system RAM with [ CALL ADDMEM ].

    Executing CALL ADDMEM with a 32K cartridge appends 8K - The Basicalc model ignores
    the other 24K (which can also be useful, but that's for another day).

    To append an entire 32K cartridge a loadable sub-program, MEMADD.SUB must be used.

    OK, you already know all that - But what if you don't want to append the entire 32K for some
    reason - Possible?

    Apparently it is. To reset the partition to (say) >8000, try the following:

    1) NEW ALL
    2) RUN "100.LOAD.PGM"
    3) "100.POKE.SUB"
    4) "Q"
    5) NEW
    6) CALL POKE(8192,127): CALL POKE(84,127): NEW

    FRE(0) now indicates 23993 bytes of BASIC-usable RAM., with 16K of the cartridge still
    above the "partition".

    Seems to work normally here - YMMV, & I'd like to hear about it if it does.

    Jack

  2. #2

    Default

    Hmm, this revision resets the partition <and> survives cycling power...

    NEW ALL
    CALL POKE(8192,127): CALL POKE(84,127): CALL POKE(8212,255): NEW

    Downloading & running pgms, with PCIF & my homebrew serial PC link, both
    works. So far...

    Jack

  3. #3

    Default

    Quote Originally Posted by JGardner View Post
    Hmm, this revision resets the partition <and> survives cycling power...

    NEW ALL
    CALL POKE(8192,127): CALL POKE(84,127): CALL POKE(8212,255): NEW

    Downloading & running pgms, with PCIF & my homebrew serial PC link, both
    works. So far...

    Jack
    Hey Jack.

    Resurrecting an old thread. Considering soldering a 32K chip to the 74 (with a shut off switch if you want to use the cartridge) to see if I can put 32K in the cartridge space. Have enough knowledge of the board to see how I can put that chip at >4000-BFFF?

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