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DM8127 8-bit NAND flash issue

Hsu robert
Prodigy 10 points

Hello,

When I measured NAND flash timing at DM8127, I can't find the Hi-Z state of I/O pins which I have pull-high and pull-low 1Kohm resistance (see following picture). And I am sure that was controled by controller (DM8127). Is this case OK? Or what can I do for output Hi-Z state at I/O pins?

  • 0
    TI__Genius 10180 points

    Hi Robert,

    Based on the command codes in the diagram (30h and 31h) it appears you intend to do a NAND PROGRAM.  In this mode the GPMC lines will be in output state and driving either a 0 or a 1.  Unless you are expecting NAND flash to come back with a status response, you don't have to drive the output to High-Z mode.

    On the other hand, if you are doing a NAND READ or having GPMC in standby, you may want the signal lines in High-Z state to ensure incoming data value are registered correctly.  High-Z (no-output) can be achieved by setting the GPMC lines to input mode, or driver off mode if the module is not in use.  

    Can you elaborate further on how the pull-ups and pull-downs you mentioned were setup?  Also out of curiosity, what is the use case for your system?

    Best,

    Shiou Mei