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Last Post 22 Jun 2015 08:31 AM by  Adam Ford
emifa_clk
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albert Ryu
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18 Jun 2015 09:24 PM

    I have two cpu module, one is the OMAP-L138 SOM-M1 Rev A, the other is the OMAP-L138 SOM-M1 Rev C.

    I try to use the emifa interface to the FPGA.

    then two cpu module emifa_clk is different A and C.

    Rev A is 100Mhz.

    Rev C is 25Mhz.

    I want to use the Rev C, but i need 100Mhz for emifa_clk.

    How can i set the emifa_clk configuration?

    Adam Ford
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    Posts:793


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    19 Jun 2015 01:01 PM
    I am looking through the documentation and I don't see anything obvious as to why the clock would be slower. Do you have specific model numbers that I can review their history? We make several different versions of the SOM-M1.

    Are you using the stock Linux that we provide or something else?

    adam
    albert Ryu
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    21 Jun 2015 09:35 PM

    Rev A Product Number : 1017855 / 461M00164

    Rev C Product Number : 1024505 / 1515M00346 / SOMOMAPL138-10-1602QHIR-C

    Adam Ford
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    22 Jun 2015 06:58 AM
    I am going to review the history of those modules this morning. Are you using the Linux BSP that we distributed or something else?

    adam
    Adam Ford
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    22 Jun 2015 08:28 AM

    According to the datasheet, it should be able to support 100MHz, section 6.10.3
    http://www.ti.com/lit/ds/symlink/omap-l138.pdf

    The Rev C version uses Revision 2.3 of the silicon from TI.

    In doing this update, we also implemented a change per TI's direction to help reduce ESD events in section 2.1.4. See the TI Errata documentaion: http://www.ti.com/lit/er/sprz301m/sprz301m.pdf

    The errata suggests making some changes to the code to adjust the clocking to make sure the correct source is used since it's changed in the newer implementation. They have an example in section 2.1.4 of the above errata reference.

    adam



    Adam Ford
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    22 Jun 2015 08:31 AM
    I don't know if you have the technical reference manual located here: http://www.ti.com/lit/ug/spruh77a/spruh77a.pdf

    Section 7.3.3 covers the EMIFA clocking. The OscIn is set to 25MHz, but you can use various clocking schemes listed there to set the EMIFA to 100MHz

    adam
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