NXP Designsのトピック2 Questions about FlexRAM

2 Questions about FlexRAM

kmh48301 — Thu, 03 Sep 2020 02:12:45 GMT

Hi. I'm using S32k144.

But the forum dosen't work for me. so I'm posting here.

1. FlexRAM is slower than SRAM

Please see the attachment. (it's from AN11983 p11)

When I see flash memory map, I think FlexRAM is also contiguous addresses.

but this is saying non-contiguous...

and is that why the FlexRAM is slower than SRAM?

FlexRAM is not static RAM (SRAM)?

2. "a background pattern of all ones" ???

I saw "a background pattern of all ones" several times in NXP documents..

But I have no idea what it means since I'm not native English speaker,,

Please explain to me

Thanks

Best regards,

Phillip

Re: 2 Questions about FlexRAM

kmh48301 — Thu, 03 Sep 2020 02:15:48 GMT

Re: 2 Questions about FlexRAM

lukaszadrapa — Mon, 07 Sep 2020 08:22:05 GMT

Hi,

1. This is given by architecture, not by the RAM itself. As you can see, the memories are sitting on different places which inserts some difference:

2. "background pattern of all ones" means, that memory controller will initialize all bytes in FlexRAM allocated for EEE to "0xFF" (all ones) and then it will copy down valid data/records from backup flash. So, non-written words have default value 0xFFFFFFFF.

Regards,

Lukas

Re: 2 Questions about FlexRAM

kmh48301 — Mon, 07 Sep 2020 23:07:04 GMT

Thank you so much. i thought wrong way. hahaha