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AM3354: DDR3 and settings

Colombo Carlo
Mastermind 21570 points
Part Number: AM3354

Hi everybody , 

in production  I m moving from  micron DDR3  to  ISSI  

MICMT41K128M16JT-107 IT:K

IS43TR16128DL-107MBLI

they are pin2pin and I used app note  getting numbers  hereunder :   

My question is  : can I use ONLY Micron  values  ( so to have only 1  binary for all my boards  , no matter DDR3 in use ) ?

ISSI values are in Micron range , but not the optimal one , is it an issue ?

ISSI:

***************************************************************

                The Slave Ratio Search Program Values are...

***************************************************************

PARAMETER                       MAX  |  MIN  | OPTIMUM |  RANGE   

***************************************************************

DATA_PHY_RD_DQS_SLAVE_RATIO    0x06c | 0x005 |  0x038  | 0x067

DATA_PHY_FIFO_WE_SLAVE_RATIO   0x1c1 | 0x050 |  0x108  | 0x171

DATA_PHY_WR_DQS_SLAVE_RATIO    0x10a | 0x031 |  0x09d  | 0x0d9   ??????

DATA_PHY_WR_DATA_SLAVE_RATIO   0x14a | 0x071 |  0x0dd  | 0x0d9 ????

***************************************************************

vs   Micron:

***************************************************************

DATA_PHY_RD_DQS_SLAVE_RATIO    0x06d | 0x004 |  0x038  | 0x069

DATA_PHY_FIFO_WE_SLAVE_RATIO   0x1bd | 0x049 |  0x103  | 0x174

DATA_PHY_WR_DQS_SLAVE_RATIO    0x0f1 | 0x013 |  0x082  | 0x0de

DATA_PHY_WR_DATA_SLAVE_RATIO   0x131 | 0x053 |  0x0c2  | 0x0de

***************************************************************

any suggestion ?thank you 

BR
Carlo

  • +1
    TI__Guru 68890 points

    Hi Carlo, yes you can probably use the same binary for both, just understand that you won't have the optimal timings, but it looks like you have a lot of timing margin to work with.  I would take the highest minimum of the two and the lowest maximum for each of the parameters, and then choose the value in the middle.  This should satisfy both devices.  For example, for DATA_PHY_WR_DATA_SLAVE_RATIO, choose max 0x131, min 0x71.  Thus your optimum value for both would be

    (0x131 - 0x71)/2 + 0x71 = 0xD1

    Regards,

    James