topic Re: After HyperRAM initialization,the initial values in memory are not 0 in i.MX RT Crossover MCUs

After HyperRAM initialization,the initial values in memory are not 0

Vinos — Tue, 24 Oct 2023 03:46:59 GMT

Chip: I.MX RT1176

I'm using two HyperRAM modules, one from Cypress with 32M and the other from ISSI with 64M. They are pin-to-pin compatible and both are connected to the FlexSPI1's Secondary Group. After initialization, the initial values in memory are not all zeros; most are zero, but some have values like 0x0a0a0a0a. The initial memory values for both chips seem similar.

Now, I have connected a 64M HyperRAM module of the same model as the 32M Cypress one(the only difference is the memory size) to FlexSPI1's Primary Group. After initialization, the memory is mostly filled with 0xAAAAAAAA and some 0x5A5A5A5A, with very few zeros.

Although the initial values appear unusual, I have tested write-read operations on the HyperRAM, and there don't seem to be any issues. The memory can be read from and written to normally.

So, I'm suspecting if the initial memory values of the HyperRAM are related to the FlexSPI configuration?

Re: After HyperRAM initialization,the initial values in memory are not 0

Omar_Anguiano — Thu, 02 Nov 2023 00:11:13 GMT

It is likely that this is done during initialization. Is there any other device connected to the same FlexSPI interface?
Specifically, how is init implemented? Are you using SDK API?

Best regards,
Omar

Re: After HyperRAM initialization,the initial values in memory are not 0

Vinos — Wed, 08 Nov 2023 08:59:27 GMT

I just initialized the SDRAM on my board with the SEMC interface, and I'm facing the same issue where the initial value is not zero.

However, what's strange is that on another boards I designed with the same SDRAM circuit, after initialization, the initial value was always zero. This makes me think it might be a hardware issue.

But in fact, this does not affect the normal use of these memories, and they can be read and written correctly.