Why should I zero-set the SRAM 0x3400000?

[amei_liu]

hardware: R45EVB

software: SW32R45_IPCF_4.3.0_D2203.exe

After I install SW32R45_ IPCF_ 4.3.0_ After D2203.exe，refer to the provided M7 routine source code, as follows:

My understanding is that:

0x34100000~0x341FFFFF: is used by A53(linux)

0x34200000~0x342FFFFF: is used by M7.

So, what is the SRAM with the address starting at 0x34000000 and a length equal to 0x100000 bytes used for? Why should I zero-set the SRAM?

[UrikRodriguez]

Hello @amei_liu,

The IPCF example zero-set the SRAM from 0x34000000 to aprox 0x347FFFFF. You can see it in the command used: 

 mw.q 0x34000000 0x0 0x100000

This command is writing zeros over 0x100000 quadwords (64 bits).

Saludos, 

Urik 

[amei_liu]

Thank you very much for your reply。

I know this is to clear the SRAM. But what I want to know is what this memory(0x3400000) is used for?

[UrikRodriguez]

Hi,

For the IPCF example that address is not used, it is only the SRAM start address, and it is good practice to initialize it. 

[amei_liu]

If it's like you said, then even if I don't reset the memory, the program should execute correctly.

But unfortunately, if I do not execute this command (mw. q 0x34000000 0x0 0x100000), an error will be reported when I load the module. As follow:

[UrikRodriguez · Accepted solution]

Hi @amei_liu,

Yes, that is because that command initializes the memory SRAM from 0x34000000 to approx 0x347FFFFF (between that range you have the shared memory for your application). 

For example if you run:

mw.q 0x34100000 0x0 0x50000

the application should still been working