Is SD Card consuming current in sleep mode while it is not performing any activity?

[Sami Ul Haq]

We are working on a project in which we have integrated multiple modules and examples like GPS, IMU Sensor, SD card, Bluetooth, etc. Now I have to manually shut down all the components (except RTC) by short pressing a button and my required current after a short pressing of a button must be <10 uA. Now my question is that is the SD card is consuming current while it's not performing anything like writing etc? If yes, how can I disable it manually after a short press and re-enable it by again pressing the button?  I will only be using the SD card when the device is on and I plugged out the USB cable otherwise I don't need an SD card and must be off to minimize the current. 

I am using NRF52840 development board and SDK 17.0.2 and soft devices s140.

Kind Regards,

Sami Ul Haq

[Edvin]

Hello,

I believe this question should have been directed towards the manufacturer of the SD card reader. 

From the nRF's point of view, I guess the only current consumption would be related to the SPI (assuming the SD card reader is interfacing via SPI). You can disable the SPI that is used for communication. Depending on what SPI driver that is being used, the disable APIs are a bit different (I don't remember how it is for SPI in SDK 17.0.2), but make sure that it sets the GPIOs configurations back to default (disconnected input). I don't know how you measure the current, and if the SD card reader is part of that current consumption. If it is, I would recommend that you separate it (power it from another source, to see what current is drawn by the nRF and what power that is drawn from the SD card reader. 

General tip:

If you see a higher than expected current consumption after you have disabled everything, try to compare it to an alternative application where you don't enable it at all. If the current consumption is the same, then you should be good. If you see that when you enable -> disable a particular peripheral, that the current consumption doesn't go back down, then investigate further with that module/peripheral/device. 

Also, in general, check whether it is possible to completely power down the SD card reader when it is not used (in addition to putting the SPI pins back to "disconnected inputs").

Best regards,

Edvin

[Sami Ul Haq]

Hello Edvin, Thanks for coming to help.

I will try your suggestions and will be back to you If I need further help. 

Kind Regrds,

Sami Ul Haq