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rise time/fall time for AM3874

Other Parts Discussed in Thread: AM3358

Hi,

I would like to know the GPIO signal rise time / fall time. It is not written in the datasheet.

Especially I would like to know the rise time/fall time of GPMC_OE and GPMC_WE signal. The CL is approximately 30pF.

Please let me know it.

Best regards,

Michi

 

  • Hi Michi,

    Do you need to know GPIO signal rise / fall time, GPMC signal rise / fall time or both ?

    Especially for GPMC_OE, you can check AM387x datasheet, Figure 8-21. GPMC Non-Multiplexed NOR Flash - Synchronous Single Read (GPMCFCLKDIVIDER = 0). It looks to me, that the GPMC_OE rise/fall is marked as 11 and 12. For 11 and 12 timing, you can check Table 8-33. Switching Characteristics Over Recommended Operating Conditions for GPMC/NOR Flash Interface - Synchronous Mode. For example:

    11 td(CLKH-nOE) Delay time, GPMC_CLK rising edge to GPMC_OE_RE transition  MIN H - 3(8) ns ; MAX H + 5(8) ns

    (8) For OE falling edge (OE activated) / IO DIR rising edge (IN direction) :
    • Case GpmcFCLKDivider = 0:
    H = 0.5 * OEExtraDelay * GPMC_FCLK
    • Case GpmcFCLKDivider = 1:
    ......
    For OE rising edge (OE deactivated):
    • Case GpmcFCLKDivider = 0:
    H = 0.5 * OEExtraDelay * GPMC_FCLK
    • Case GpmcFCLKDivider = 1:
    ....
     
    Depending on which case you are, you can check also figures 8-22, 8-24, 8-25.

    Use similar approach for all the rest GPMC signals timing.

    Regards,

    Pavel



  • Pavel-san,

    Thank you for your reply.

    You advised me GPMC_OE rise / fall time is marked No.11,12 on Figure 8-21. But I don't think it is rise/fall time.

    No.11 is "Delay time (GPMC_CLK rising edge to *GPMC_OE_RE transition)",

    My understanding of rise/fall time is the following.

     

    I would like to know rise time/fall time of the above difinition for GPMC signal.

    Please let me know.

    Best regards,

    Michi

  • Hello TI Support,


    We are also looking for this information,

    Datasheet specifies Rise/Fall times for GPMC_CLK and GPMC_AD in table 7-22 of AM3358 Datasheet.  We are looking for information on GPMC_ADVn/OE/WE/CS

    Could someone please provide more details?

    Thanks,

    Mikhail

  • Mikhail,

    For AM335x related questions, use our Sitara forum.

    BR
    Pavel