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Revision D TRM for AM3874(sprugz7d)

Michi Yama
Guru 10030 points
Other Parts Discussed in Thread: AM3874

Hi,

I have one question regardin latest AM3874 TRM(sprugz7d).

According to the revision history of rev.D TRM,  IDLE_LOCAL_OUT value changed from "3h" to "0h"; description changed accordingly from "100 Ohms ODT when receiver is powered down" to "ODT off".

If customer does not use the power down mode, customer does not care anything?

Please let me know.

Best regards,

Michi

  • 0
    TI__Guru**** 170625 points

    Hi Michi,

    Michi Yama said:
    If customer does not use the power down mode, customer does not care anything?

    Yes, I also think so. See AM387x TRM, Table 7-60. DDR PHY Control Register (DDRPHYCR) Field Descriptions

    [13:12] IDLE_LOCAL_ODT - This bit fields specify the ODT selection on the DDR Controller side when the receiver is powered down. IDLE_LOCAL_ODT is applicable only when DYN_PWRDN_EN is set to '1'. Please refer to Table1-16 for the supported ODT termination values.
    Recommended value is 0x0 [ODT OFF]

    [20] DYN_PWRDN_EN - Enables dynamically powering down the IO Receiver when not performing a read. This will help in reducing DDR IO power. It is recommended to set this bit to '1' always.
    When set to 1, dynamic power down is enabled. IO receiver is powered down when not doing any reads

    http://processors.wiki.ti.com/index.php/DM814x_AM387x_Power_Estimation#EMIF_0.2C_EMIF_1

    The unused DDR interface can be put into least power consuming state by the configuring it as follows

    • Enable the dynamic power down for the IOs of the unused DDR interface. This can be done by setting the DYN_PWRDN_EN bit in the corresponding DDRPHYCR register.
    • Disable ODT for the unused DDR interface by selecting the following configurations in the corresponding DDRPHYCR register.
      • IDLE_LOCAL_ODT = 0
      • RD_LOCAL_ODT =0


    Best regards,
    Pavel