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About tms320c6748 power management problems

lucy_zhu
Prodigy 190 points
Other Parts Discussed in Thread: OMAP-L137, OMAP-L138, TMS320C6748

Hi,:

        I have a problem about power pin.If some peripheral modules will never be applied in my system, such as sata.How to deal with Its 3.3v and 1.8v power supply pins and I/O pins?   

 1: Whether its power pin can connect empty ?

2:If  unused modules  have power, I/O pins can be Empty,Ground or high impedance, or others???                  

Please give me some suggestions!  

     Thanks!

  • 0
    TI__Mastermind 24340 points

    USB

    Please find the OMAP-L137/C6747 USB unused pin recommendations at:

    If I'm not using both USB0 and USB1 in my design for C6747, what should I do with the USB pins?

    For OMAP-L138/C6748, recommendation is the same as above. The only exception is to connect the USB_CVDD (M12) to a static 1.2V supply.

     

    RTC

    If the RTC is not used:

    RTC_XI can actually be tied high or low (functionally doesn't matter since the RTC would be disabled) but we suspect RTC tied low might be slightly better from a power standpoint.

    RTC_XO can be left open

    RTC_CVDD must be connected to a 1.2V source (RVDD would be the easiest)

    RTC_VSS can be connected to board ground

     

    SATA for OMAP-L138

    Signal Name Type PIN # Unused Pin Connection
    SATA_VDD PWR M2, P1, P2, N4 Static 1.2V Supply
    SATA_VDDR PWR P3 Not Connected (Recommended to Trace out)
    SATA_REG Analog N3 NC
    SATA_VSS Ground H1, H2, K1, K2, L3,M1 GND
    SATA_RXP I L1 NC
    SATA_RXN I L2 NC
    SATA_TXP O J1 NC
    SATA_TXN O J2 NC
    SATA_REFCLKN I N1 NC
    SATA_REFCLKP I N2 NC
    SATA_MP_SWITCH I E17 Mux'd with other signals

    Options:

    1. Configure as another function
    2. Configure as GPIO out and drive to known state
    3. Configure as input and apply appropriate pu/pd"
    SATA_CP_DET I D16
    SATA_LED O E18
    SATA_CP_POD O F19

     

  • 0 in reply to Mariana
    Prodigy 190 points

    Thank u,Mariana!

    I would like to ask some questions.

    1)About M14 and N16 pin , USER GUIDE recommends disconnecting,but in the EVM board schematic, the two pins labeled VSSA_USB0 VSSA33_USB0.These two proposals, which one is correct?
    2)In circuit design OMAP L138 and TMS320C6748 if there are differences?

         Thanks!

  • 0 in reply to lucy_zhu
    TI__Mastermind 24340 points

    1) http://e2e.ti.com/support/arm174_microprocessors/omap_applications_processors/f/42/p/36612/127850.aspx#127850

    2) They are almost the same. Please refer tot he datasheets for differences. Also, the you can get the schematics for the C6748 and OMAP-L138 SOM at Logic's web site.