• State TI Thinks Resolved
  • Locked Locked
  • Replies 10 replies
  • Answers 1 answer
  • Subscribers 98 subscribers
  • Views 1026 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.

DRA744: wifi module on SDIO working @ 3.3V not @ 1.8V IO interface

Colombo Carlo
Mastermind 24120 points
Part Number: DRA744

Hi everybody , 

I m in Android 4.3  and using a WIFI module attached via SDIO signals .

WIFI module can work @ 3.3 V or 1.8V SDIO IO signals , and I am on eMMC1 . 

now  using signals @ 3.3V everything is fine .   if I use 1.8V level  ( with proper settings etc )   module is not working .

what I noticed using a scope  --> no signal or bus activity by DRA744 at all ,  all signals are stuck if  IO are set @ 1.8V

I noticed in TRM  you need to start @ 3.3 V on IO  on SDcard   ( it  is in table 25-2 )  : is this needed also for SDIO ?   ( in the TRM it seems not ..)

please  where am I wrong ?

best regards

Carlo

  • 0
    TI__Guru*** 125430 points

    Colombo Carlo said:
    WIFI module can work @ 3.3 V or 1.8V SDIO IO signals , and I am on eMMC1 . 

    MMC1 has pbias cells that need to be configured appropriately.  Have you checked the associated registers?  I suspect these are your issue.

  • 0 in reply to Brad Griffis
    TI__Mastermind 24120 points

    Hi Brad , 

    ket me double check 

    thank you 

    best regards

    Calro

  • 0 in reply to Colombo Carlo
    TI__Mastermind 24120 points

    Hi Brad , 

    we  cleared bit 21 (SDCARD_BIAS_VMODE) register CTRL_CORE_CONTROL_PBIAS   cleared to  0 (0x0 = VDDS = 1.8V)

    please anything else is needed ?

    best regards

    Carlo

  • 0 in reply to Colombo Carlo
    TI__Guru*** 125430 points

    After having made that change, what is the register value?  Are you able to restart wifi after that change (maybe "ifconfig wlan0 down && ifconfig wlan0 up")?  Do you see any activity?  If you read the register a second time after trying the command, did the value stick or is something overwriting it?

  • 0 in reply to Brad Griffis
    TI__Mastermind 24120 points

    Hi Brad , 

    I can confirm you   we can rread register and it is as set  .    when  IOs are @ 1,8V  we do  not see any activity at all .   same board and same sw  when IOs are @ 3.3V  everything is fine  and activity etc 

    please what can we try/test ?

    thank you 

    best regards

    Carlo

  • 0 in reply to Colombo Carlo
    TI__Guru*** 125430 points

    What is the value? Please respond with a 32-bit hex number.

  • 0 in reply to Brad Griffis
    TI__Mastermind 24120 points

    Hi Brad , 

    it is 0x0D000000  

    regards

    Carlo

  • 0 in reply to Colombo Carlo
    TI__Guru*** 125430 points

    FYI, I'm on vacation today so likely won't be able to respond further until tomorrow.

    The value you showed does not look right to me.  That value decodes as:

    • Bit 27 SDCARD_BIAS_PWRDNZ = 1, VDDS stabilized, ok
    • Bit 26 SDCARD_IO_PWRDNZ = 1, VDDS stabilized, ok
    • Bit 25 SDCARD_BIAS_HIZ_MODE = 0, PBIAS normal, ok
    • Bit 24 SDCARD_BIAS_SUPPLY_HI_OUT = 1, VDDS = 3.3V
    • Bit 23 SDCARD_BIAS_VMODE_ERROR = 0, no error, seems like maybe there should be?
    • Bit 21 SDCARD_BIAS_VMODE = 0, VDDS = 1.8V

    Bit 21 and 24 do not agree.  I'm surprised there's not an error showing.  Can you check the physical connection?  Does it meet these conditions:

    To support the UHS-I speeds on MMC1,
    – You need a dedicated, configurable LDO connected to VDDSHV8. The EVM uses the LDO1 output
    from the PMIC.
    – Do not use this LDO to power anything else on the board since it will change dynamically at runtime.
    – The SD card's VDD signal should be connected to a fixed 3.3 V rail. In other words, the card's VDD
    must remain at 3.3 V even for the UHS-I modes of operation. Only the signaling levels change in
    these modes, not VDD.
    – Pullups on the SD/MMC signals should go to the LDO rail such that their voltages coincide with the
    mode of operation.

    Can you please also report the value of CTRL_CORE_PAD_MMC1_CLK (address 0x4A00 3754)?  Is bit 18 set?

    Finally, what's the value of CTRL_CORE_CONTROL_SPARE_RW (address 0x4A00 2E68)?  Normally it is zero.

  • 0 in reply to Brad Griffis
    TI__Mastermind 24120 points

    Hi Brad 

    sorry for taking time in replying you but some vacations perido 

    I ll be back as soon as I can 

    bets regards

    Carlo

  • 0 in reply to Colombo Carlo
    TI__Mastermind 42515 points

    Hi Carlo,

    I will close the thread now, if you have any update you can write here to reopen it or create a new thread if this one gets locked due to timeout.

    Regards,

    Yordan