Re: Question regarding SDR104 bus speed mode

Philip Rakity
2011-07-18T15:31:07Z

On Jul 17, 2011, at 10:21 PM, Subhash Jadavani wrote:

> Arindam/Philips,
>
> Can you help me with below query?
>
> Regards,
> Subhash
>
>> -----Original Message-----
>> From: linux-mmc-owner@vger.kernel.org [mailto:linux-mmc-
>> owner@vger.kernel.org] On Behalf Of Subhash Jadavani
>> Sent: Thursday, July 14, 2011 5:09 PM
>> To: linux-mmc@vger.kernel.org; prakity@marvell.com;
>> arindam.nath@amd.com
>> Subject: Question regarding SDR104 bus speed mode
>>
>> Hi Arindam, Philips and All,
>>
>> According to SD 3.0 spec (section 3.9.6), cards may require current
>> upto
>> 800 mA while running in SDR104. However Max. supported current from
>> PMIC
>> regulator connected to sd card slot on my board is 600mA.
>>
>> I have these questions:
>> 1. So does this mean we can't support the SDR104 mode if regulator
>> current
>> driving capacity is not upto 800 mA?
>>
>> 2. I am able to make SD card run in SDR104 mode even if the max.
>> current
>> supplied by regulator is upto 600 mA. So is this 800mA requirement is
>> **must** condition to support SDR104 mode reliably?

Check the datasheet for the chip vendor you are using assuming the
chip is soldered down on the board. Our our system the eMMC chip
is much more flexible then the JEDEC spec allows.

>>
>> Regards,
>> Subhash
>>
>> --
>> Sent by a consultant of the Qualcomm Innovation Center, Inc.
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
>> Forum.
>>
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>