• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 98 subscribers
  • Views 466 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.

OMAP-L13x - BSDL: selecting DDR I/O strength in Boundary scan?

AnBer
Mastermind 30190 points

Team,

Question about Boundary scan and setting the DDR I/O driver strength (in blue below):

I have a query on what drive strength that you configure for a Texas Instruments OMAP-L138BZCE device when under boundary scan control please, in particular the EMIFA interface.

I am currently using boundary scan tools to exercise the OMAP processor I/O to prove signal integrity of the hardware, the EMIFA interface is connected to both flash and an FPGA on our board. When running simulations, actual board level measurements are not quite stacking up against what I would expect from the simulation tools, unless the i/o pins have been set to a weak drive strength. Could you confirm how you set the drivers to operate please when under boundary scan conditions please.

I would assume that from BSDL you can not access the DDR controller registers to control this. Correct?
Are there alternatives methods?

Thanks and best regards,

Anthony

/O driver strength:

  • 0
    Prodigy 35 points

     

    To Clarify,

    I am NOT concerned with the DDR interface but the EMIFA port in my application. It would be good to know, however, what the drive strength for all pins is under boundary scan mode.

    Thanks,

    John

     

     

  • 0 in reply to John Ashley
    TI__Mastermind 30190 points

    John,

    I think that drive strength is only programmable for DDR type of interface.

    For the EMIF used in async mode (for Flash or FPGA), as far as I know, the driver strength is known and not programmable. Still at the device level there are elements that influence the strength:
       - 1.8 vs 3.3 V operation (see for example the figures 7 of the SPRZ301h)
      - internal pull-up, pull down enabled or disabled (see section 10.11.5 of SPRU77A).
    You could look at the IBIS model that we provide to have a closer look at the driver caracteristic:
    http://www.ti.com/product/omap-l138#simulationmodels
    In the Ibis model there are entries for all the above scenario (1.8. 3.3, with pull up, with pull down, without pull up/down).

    Hope it helps.

    Anthony