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Sitara and DDR3 speed selection

Luis Caruso
Prodigy 150 points

Other Parts Discussed in Thread: AM3359

We are designing a board with AM3359 (ZCZ) and DDR3 (one chip), and facing some difficulties in component selection.

What we want to know is the possibles combinations of the 2 chips.

1 - Reading the DS (table 3.6) it seems tha the only mode to support DDR3 is OPP100 at 400 MHz. Is it correct? If not what is correct?

2 - Reading further (table 3.7) it seems that OPP100 is only supported for Sitaras of 300 and 600 MHz grades. Is it correct? If not what is correct?

3 - What procedure to follow to adapt the DR3 to the Sitara in terms of speed including the multipliers and dividers of the formula bellow:

DDR_CLK frequency = (DDRPLL input clock frequency x mulitplier)/((pre-divider+1)*post-divider)

Suppose we are trying to use the fastest combination possible of the two chips.

Thank you!

Luis

  • 0
    TI__Guru**** 393215 points
    Hi Luis,
     
    For DDR3 selection look in section 5.6.2.3 of the datasheet (newest revision is F). DDR3 is supported at OPP100 and above. OPP50 does not support DDR3. Possible DDR3 clock speeds are from 303MHz to 400MHz. OPP100 is supported for all AM335X speed grades.
  • 0 in reply to Biser Gatchev-XID
    Prodigy 150 points

    Hello Biser.

    Thanks for your answer. I checked the numbers, it seems to be OK. So I think we can use  DDR3 memory, part No. MT41J128M16JT-125, as the Starter Kit, with DDR3-1660 speed bin and parameters: CL = 6 CWL = 5 tCK (AVG): 2.5 - 3.3 ns.

    In this other thread "http://e2e.ti.com/support/arm/sitara_arm/f/791/t/223223.aspx", AM3359 DDR3 speed, Renjith gives the speed a maximum of 606 MHz (???), and the costumer get "AM3359 spec is 532MHz (Data rate)" ???.

    What are the right numbers?


  • 0 in reply to Luis Caruso
    TI__Guru**** 393215 points
    Hi Luis,
     
    For AM335X in DDR3 configuration the minimum DDR_CLK frequency is 303MHz and the maximum is 400MHz. This is clock frequency, not data rate. Data rate is usually considered as 2x clock frequency.