TDA4VM OCM data retention after reset

Hi Xie,

Which reset sequence are you applying here? 

Typically flash should be used as non-volatile memory. But if you are just doing main domain reset, then mcu domain peripherals will retain its values.

Regards,

Brijesh

Hi,Brijesh

Brijesh Jadav said:

Which reset sequence are you applying here? 

We are using Sciclient_PmDeviceReset to reset all SoC.

Brijesh Jadav said:

Typically flash should be used as non-volatile memory. But if you are just doing main domain reset, then mcu domain peripherals will retain its values.

Our consideration is to save the current exception data in RAM when the SoC enters exception mode, because it is more difficult to operate OSPI to write Flash in exception mode

Regards,

Xie

Hi Xie,

According to below statement, do you see this memory at offset 0x41c00000 retaining values? I really doubt it. 

"I wrote 0xAA55AA55 at address 0x41c00000, then a reset request, after the reset I read the data at address 0x41c00000 is still 0xAA55AA55."

Regards,

Brijesh

Hi Xie,

I think the option is to use flash OSPI or eMMC, as i doubt there is any non-volatile memory, which can preserve content over power cycles...

Regards,

Brijesh

Hi,Brijesh

Brijesh Jadav said:

According to below statement, do you see this memory at offset 0x41c00000 retaining values? I really doubt it.

I didn't implement this, I was asking if you could implement something similar, and it doesn't have to be 0x41C00000, it could be some other address.

Brijesh Jadav said:

I think the option is to use flash OSPI or eMMC, as i doubt there is any non-volatile memory, which can preserve content over power cycles...

I found some instructions in the TRM，the address is 0x40280000,as below figure

Regards,

Xie

Hi Xie,

This is not applicable when you powercycle the SoC. 

I dont think there is any non-volatile memory in SoC to retain contains across reboots.

Regards,

Brijesh

Hi，Brijesh

     Did you try to achieve it?

    After my own test, PSRAM can complete the function I want, the only drawback is that the space is too small, so is there any other RAM that I don’t know can also complete this function

Regards,

Xie

Hi Xie,

Can you please share details on PSRAM? There are multiple PSRAMs on device? 

Most likely PSRAM also will not retain contents across powercycle.  so want to check which PSRAM is retaining contents. 

Regards,

Brijesh

Hi,Brijesh

    The PSRAM address is 0x40280000, and I have tested and determined that PSRAM can meet our needs but the 512B space is too small。

Brijesh Jadav said:

There are multiple PSRAMs on device? 

I only found this place in TRM. I'm here to ask you for help to determine if there are other places that can perform the same function as PSRAM（0x40280000）.

Regards,

Xie

Hi Xie,

I don't see the values at this location remain persistent. I wrote some value at 0x40280000 from mcu_r5f and powercycle the board, i dont see same value. 

Are you sure you are seeing same value across power cycle at this location? From which core are you trying to access this memory?

Regards,

Brijesh

Hi,Brijesh

Brijesh Jadav said:

I wrote some value at 0x40280000 from mcu_r5f and powercycle the board

     What do you mean powercycle?Power down then power up?

    I said before that we are using warm reset！

   Regards,

Xie

Hi Xie,

oh ok, i thought you are doing power off and on.

Let me check and get back to you.

Regards,

Brijesh

Hi Xie,

Any further questions on this thread? Let us know otherwise if we can close this thread.

Regards,

Brijesh