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Thread: 27C322 as a 32mbit V Rom

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    Hi XX,

    You can use macronix, I know that they are eeproms, but they work at 16 bit.

    Un saludo

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    JammaNationX
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    Quote Originally Posted by fremen View Post
    Hi XX,

    You can use macronix, I know that they are eeproms, but they work at 16 bit.

    Un saludo
    So they can work as 8 bit for V roms?

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    Hi XX,

    Yes they work at 8 bit.
    MX29L3211

    Un saludo
    Last edited by fremen; 08-28-2012 at 04:20 PM.

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    Buyicnow

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    Fake account, shill troll for Christophe Ratel. Use extreme caution when dealing with.
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    Quote Originally Posted by fremen View Post
    Hi XX,

    Yes they work at 8 bit.
    MX29L3211

    Un saludo
    Can i program those with a TOP3000 programmer?


    Quote Originally Posted by fremen View Post
    Yes, they are sop instead dip socket.
    But there are adaptors to convert sop to dip, and you need an adaptor for the programmer also
    Do they need to be programmed before they go on the adaptors? Cause i see you can buy them allready on the adaptors as well.

    Do the adaptors lower the voltage to 3.3v or is there something else required?

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    Hi mate,

    Quote Originally Posted by NEO-GEO man View Post
    Can i program those with a TOP3000 programmer?
    Unfortunately top3000 doesn't support the MX29L3211

    Quote Originally Posted by NEO-GEO man View Post
    Do they need to be programmed before they go on the adaptors? Cause i see you can buy them allready on the adaptors as well.
    No, you can solder them in the adaptors then to programm them. The answer to XX about the programmer adaptor (not about the eeprom adaptors) was in order to use the programmer with another devices than MX29L3211 or to use the MX32L3211 for other pourposes

    Quote Originally Posted by NEO-GEO man View Post
    Do the adaptors lower the voltage to 3.3v or is there something else required?
    You don't need anything to lower the voltage during the programmation even if you solder the eeprom in the adaptor, the programmer take in to account that you're burning a 3.3v device, after yes, you need two diodes in line to lower the voltage since the carts provide 5v.

    Saludos
    Last edited by fremen; 01-10-2013 at 09:22 AM. Reason: clarifications

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    Cheng's Errand Boy

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    Quote Originally Posted by Xian Xi View Post
    How do I build a multiplexing circuit with two 74HC257 chips in order to use the 27C322 as a V rom?
    Use two 245 chips and one inverter. Map odd byte to one of them, even one to the other, drive A-1 to even bus /OE, /A-1 to even bus /OE.

    Should do the trick but it's going to be a big adapter.

    Edit:

    Checked 257, simpler design indeed, no inverter required.
    What you want should looks like this
    Last edited by Pedrobear; 08-29-2012 at 06:56 PM. Reason: MOAR

  10. #10
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    Necro bump

    Can you merge 16mbit Vroms onto 322s? ....like V1+V3=V1 and V2+V4=V2
    It seems like the Neo-PCM chip works as a multiplexer for the V roms.
    If I move the jumper to A20 on a progbk1 will 322s drop right in?
    Clowns Suck


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    Hi,

    Quote Originally Posted by bustedstr8 View Post
    Necro bump

    Can you merge 16mbit Vroms onto 322s?
    Yes, but doesn't work correctly because 27C322 only works at 16bits.

    Quote Originally Posted by bustedstr8 View Post
    ....like V1+V3=V1 and V2+V4=V2
    No, V1+V2=V1 and V3+V4=V2

    Merry Xmas and Happy New Year

  12. #12
    Bashful Neophyte

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    Quote Originally Posted by Pedrobear View Post
    Use two 245 chips and one inverter. Map odd byte to one of them, even one to the other, drive A-1 to even bus /OE, /A-1 to even bus /OE.

    Should do the trick but it's going to be a big adapter.

    Edit:

    Checked 257, simpler design indeed, no inverter required.
    What you want should looks like this
    Could you upload the design again please?

    Thanks!

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