Flash chips running with 3.3v and have 5v input tolerance


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  1. #1
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    Default Re: Flash chips running with 3.3v and have 5v input tolerance

    well after many a search , i did not find any flash that allowed for 5v tolerant inputs ,
    i have interfaced the 8mb flash via level converter 75LVX125 for the CE pin for the moment , have tied high the W and Hold lines high and when data is complete for the menus/fonts etc , with software protect those sectors which are used from further writing.

    the PCB has been designed to support the SD and adding a flash chip is a pain but not one that is hard to do. for an extra CE required
    resistor divider may do as well , but ill test after it working for add on board when done.

    what i have found is some of the flash chips support duel / quad spi , which if you got the pins for connecting the W and hold pins , can allow for upto 4 bit write/ reads - somethin i not seen as example in code

    as i have to use a SD and using SDFS3.bas include for it , iwill use some of the same varables so i am not boging down the cpu with more duplicated varables for the buffers ,

    see how it goes in the next few days and post the code , cos i really hate doing the wheel if i can avoid ,

    Flash chips have advantages in cost/ speed/ size over the EEprom and I2C , even after the need for level converters

    one day wish list is that PIC'S have level converters built in on all ports but that a big ask as they dont want to do it it seems

  2. #2
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    Default Re: Flash chips running with 3.3v and have 5v input tolerance

    Simple answer is to run the PIC at 3.3 volts. In fact, many of the PICs are designed for this voltage. So just make the switch to low power and be done.
    Dave
    Always wear safety glasses while programming.

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