Question regarding SDR104 bus speed mode

Question regarding SDR104 bus speed mode

[Subhash Jadavani]

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?

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.

RE: Question regarding SDR104 bus speed mode

[Subhash Jadavani]

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?
> 
> 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.
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: Question regarding SDR104 bus speed mode

[Philip Rakity]

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.
>> 
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

RE: Question regarding SDR104 bus speed mode

[Subhash Jadavani]

> -----Original Message-----
> From: linux-mmc-owner@vger.kernel.org [mailto:linux-mmc-
> owner@vger.kernel.org] On Behalf Of Philip Rakity
> Sent: Monday, July 18, 2011 8:57 PM
> To: Subhash Jadavani
> Cc: linux-mmc@vger.kernel.org; arindam.nath@amd.com
> Subject: Re: Question regarding SDR104 bus speed mode
> 
> 
> 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.

Philips,
This is not for eMMC/MMC spec and cards. This is for SDR104 mode from SD3.0
spec. and relevant for SD UHS-I cards only.
Any comments of running SDR104 with 600mA driver current? Is this fine
according to SD3.0 spec?

> 
> >>
> >> 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.
> >>
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe linux-mmc"
> in
> >> the body of a message to majordomo@vger.kernel.org
> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >
> 
> --
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