Program Partition and IFR address

[kmh48301]

Hello!

I'm trying to partition FlexNVM.

in order to partition, I read S32k-RM and AN11983 first. and i got question.

in s32k-rm page 835.

-------------------------------------------------------------------------------------------------------------

3. FlexNVM EEPROM partition — The amount of FlexNVM memory used for
emulated EEPROM backup (see Figure 36-9). In order to achieve specified w/e cycle
endurance, the emulated EEPROM backup size must be at least 16 times the
emulated EEPROM partition size in FlexRAM. For parts other than the 2MB
configuration (with interleaved DFlash), the FlexNVM may be split according to the
Program Partition command, allowing for part EFlash and part DFlash. For example
a 64kB FlexNVM could be partitioned for 32kB emulated EEPROM and 32kB
DFlash. To maintain the full specified w/e endurance in the emulated EEPROM
system, the number of records stored in FlexRAM should be limited to maintain the
1:16 ratio of RAM to NVM. The management of total number of records is left to the
user.

-----------------------------------------------------------------------------------------------------

I think 'program partition command' includes how I split the flexNVM.

as i'm using s32k144, my EEE size can be only 4KB 

(the choice is just two : 0 or 4)

"the emulated EEPROM backup size must be at least 16 times the
emulated EEPROM partition size in FlexRAM."

so that paragraph means that do i have to set the E-Flash size as 64KB???

but somewhere i read it could be 32kb or more...

I think that paragraph is telling another things..

plus

what's address mean in this table?

I think IFR is not mapped memory.

So we can't access this memory like mapped memory.

Can I access IFR through that address?

But according to memory map, that address belongs to P-Flash..

could you please help me??

[kmh48301]

p.s S32K community has still problem. We can't post to S32K community.

The label doesn't pop up when I post.

[dianabatrlova · Accepted solution]

Hello,

Just to be clear, there are two programmable options that are used to define the exact memory use for a system:

1. EEE size (emulated EEPROM partition size in FlexRAM) which can be set to 0 or 4 KB for the S32K14x

2. FlexNVM partition (EEPROM backup size) can be set to 64 KB or 48 KB or 32 KB for the S32K14x

I would like to mention an important note in the AN11983:

"The way to increase the ratio of RAM to NVM beyond 16 is to use less RAM addresses in the application. If the user only writes to 2 kB of the total 4 kB of FlexRAM for S32K14x devices, then ratio effectively changes from 1:16 to 1:32, doubling the w/e cycle endurance."

So, you do not need to write/erase the whole 4 KB. 

About IFR: 

what's address mean in this table?

The data flash 0 IFR is located within the data flash 0 memory block and includes partition information as you can see in the field description in the table. Also, see description "36.4.3.1 EEPROM data set size" and "36.4.3.2 FlexNVM partition code" in the RM rev 12.1

I think IFR is not mapped memory.

So we can't access this memory like mapped memory.

As you said the IFR is not accessible or mapped, so it cannot be read.

Can I access IFR through that address?

The partition information is programmed in the Flash IFR by the program partition command.

"After launching program partition code, EEPROM backup memory size and EEESIZE values are saved on data flash IFR region"

I hope ti helps.

Best regards,

Diana

[kmh48301]

Hi

Thank you for kind explanation.

I understood question 1 !! I should have read AN11983 more.

But question 2 : IFR address : We can't read the value of data flash 0 IFR map as developer intended.

So, in that table, what Address Range mean? 

I know this address is not in memory map.

and terminology question in RM : "0"

Data flash "0" IFR map

Program flash "0" IFR map

"0" memory block

what's "0" mean?

I guess it is about flash memory hardware feature. but i'm not sure...

Please give me a hand little more!

Thanks

Best regards,

Phillip