• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 34 subscribers
  • Views 478 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LMH1297: SPI Fast EOM Operation

K.Yaita
Guru 29720 points

Part Number: LMH1297

Hi Team,

The programming guide shows "SPI Fast EOM Operation" procedure in page 14.

>7. Repeat Steps 5 and 6 another 4095 times (64 × 64 cells).
Does LMH1297 support increment mode* to shorten the 4095 times read time?
* When a first address is specified, register address is incremented by one and can be read continuously

Best Regards,
Yaita

  • 0
    TI__Guru* 93570 points

    Hi Yaita-San,

    Yes data is streamed out. Meaning it automatically goes to the next cell until we get to the last cell#4096).

    Regards,, Nasser

  • 0 in reply to Nasser Mohammadi
    Guru 29720 points

    hi Nasser-san,

    Thank you for your reply.
    I understand we should read Reg 0x25 and Reg 0x26, repeat 4096 times (64x64 cells) for SPI Fast EOM Operation.

    1)
    It seems 64x64 cells can be read to set Reg 0x25 only with SMBus Fast EOM Operarion.
    Can it apply SPI Fast EOM Operation?
    I would like to ask if we can skip Reg 0x26 to be set. 

    2)
    If the answer for 1) is yes, can we read 64x64 cells to set address Reg 0x25 only and do burst read?
    I believe LMH1297 doesn't increment / decrement the address automatically but would like to confirm just in case.

    Best Regards,
    Yaita

  • 0 in reply to K.Yaita
    TI__Guru* 93570 points

    Hi Yaita-San,

    Please note LMH1297 programming guide.

    1). As noted in section 3.10.1, in SMBus interface, when you do a burst read, the address automatically increases to the next location. Therefor when you do a burst read of two bytes it reads from location 25 and then automatically the next location is 0x26. A read of 0x26 triggers the LMH1297 state machine to increment to the next cell.

    2). SPI operation could be much faster. Therefor we check reg 0x24[0] to make sure data is ready then we do single byte read to first reg 0x25 and then we do another read operation to read reg 0x26(as noted in programming guide section 3.10.1.2). Please note SPI interface does not have burst read option where the 2nd read would increment to the next location. In SPI we need to read each location individually. We need to follow programming steps as noted in the programming guide.

    Regards,, Nasser

  • 0 in reply to Nasser Mohammadi
    Guru 29720 points

    Hi Nasser-san,

    I appreciate for your kind and clear explanation!
    I understand.

    Best Regards,
    Yaita