MMC access from PRU on AM335x in sleep for SD card

Rich_MTL

We need to write to the MMC interface (an SD card) whist the CPU is in sleep mode (running Linux) - has anyone tried this before and are there any code examples we could quickly reuse?

Thanks

over 10 years ago

0 Biser Gatchev-XID over 10 years ago

TI__Guru**** 393215 points

Hi Rich,

In DeepSleep modes AM335X main oscillator is off, so I don't think this would be possible.

0 Rich_MTL over 10 years ago in reply to Biser Gatchev-XID

Prodigy 60 points

Is this not possible in any other low power modes such as Deepsleep1/Standby where PD_PER is on?

Thanks

Rich

0 Biser Gatchev-XID over 10 years ago in reply to Rich_MTL

TI__Guru**** 393215 points

Please check Table 8-13 in the AM335X TRM Rev. K. It lists all power modes and corresponding states.

0 Rich_MTL over 10 years ago in reply to Biser Gatchev-XID

Prodigy 60 points

Ok thanks. Are there any code examples available for SD card access on PRU ? e.g. with fatfs lib ?

0 Biser Gatchev-XID over 10 years ago in reply to Rich_MTL

TI__Guru**** 393215 points

At the moment I don't think there is such code example.

0 Frank Walzer over 10 years ago in reply to Rich_MTL

TI__Mastermind 44306 points

Rich_MTL said:
Are there any code examples available for SD card access on PRU ? e.g. with fatfs lib ?

I doubt that makes sense... Just try to compile any of the required libs and see if it fits the 2k instruction space of a PRU on AM335x.

Not sure what you want to achieve?

regards,

Processors

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MMC access from PRU on AM335x in sleep for SD card