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Thread: Using 1gb eeproms with two chip select pins

  1. #1

    Using 1gb eeproms with two chip select pins

    I've been trying to figure out how to use dual-die eeproms, like the PeskyProducts 1GB memory board shown here.

    Dual die chips have two dies stacked on top of eachother, and share all pins except for an independent chip select for each one. This crams twice as much memory into the package, but only one die (half of total memory) can be used at a time.

    I can see how I can include the SPI flash library and use one chip with one die, but I can't see how I would use multiple ones...

    Can someone enlighten me?


  2. #2
    Senior Member PaulStoffregen's Avatar
    Join Date
    Nov 2012
    It really depends on the specific code you're using, which isn't mentioned in your question.

    If using a library like SerialFlash which only supports 1 chip with 1 chip select, you'll probably need to make a complete 2nd copy of all the code, and then do quite a lot of editing to rename *everything* with global scope.

    If using a library where you can create separate instances where each gets configured with the CS pin, just create 2 objects and access the 2 dies as if you had actually connected 2 separate chips.

    With a tremendous amount of work, in principle someone could create a library which accesses this sort of chip (or an array of separate chips) as one large logic storage unit. But as far as I know, nobody has actually done this and published as an open source Arduino lib. I can tell you I have no plans to do so, and I have previously urged Kris to sell memory products using a single CS signal.

  3. #3
    Than you for the excellent explanation! (And thanks for Teensy too.)

    I'm using SerialFlash, which had me a bit confused as it only works with single die chips. It strikes me now that with the massive flash chip sizes available, it's not really necessary to spec dual die chips.

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