i.MX8M Mini: sharing peripheral access during runtime between M4 and A53

[craigeasdale]

Hello,

I've got an application where I want to store a stream of data in a low power mode on SD card, then copy this data elsewhere at regular intervals.

To do this I plan to use the M4 core to handle the incoming data, storing it on SD card using the SDIO peripheral. When it comes time to copy/process the data the A53 core would be started, at which point it has to access the SDIO peripheral/SD card to copy the data elsewhere. While this happens the M4 would buffer incoming data for as long as the transfer takes.

This approach is dependent on being able to reassign usage of the SDIO peripheral from M4 to A53 and back again without powering down either core. I'm not sure of the limitations of the shared peripherals, so I thought I should ask here; Is this possible?

Thanks

[AldoG]

Hello,

This is not possible, please note that the Cortex M4 cannot access this peripheral.

Best regards,
Aldo.

[craigeasdale]

Thanks for the feedback.

Could you tell me where to find the information about what core has access to which peripherals? I'm sure I saw it a while ago but can't for the life of me find it now.

[AldoG]

Hello,

Sorry for the confusion I was not clear enough, what I meant is that It is not possible to share peripherals (such as one of the SDCard interfaces) between the Cortex-A and Cortex-M sides of the SoC without coordination between the two operating environments. Uncoordinated, simultaneous access to the same peripheral register set between the C-A and C-M will result in conflicts in data and device state leading to data corruption and possibly even system crashes.

Best regards,
Aldo.