FlexNVM and FlexRAM configuration

[preetmehta]

Hello,

I am trying to back up my system data of around 5 KB into FlexRAM in Kinetis (K61). I have referred KQURG and AN4282 and device specific RM. reading all that I was able to summarize the detail as follows.

1. endurance of the FlexRAM is totally dependent on the variables in the equation.

2. from that equation I was able to conclude that if I use minimum FlexRAM for EEE and whole FlexNVM as E-flash I get the max endurance keeping partition factor 1/8 (which is the division factor only that comparitively makes the endurance higher than 1/2 or 1/4)...so lets say for my 5 KB of data, can I keep the EEE 32 bytes (which is the possible minimum)???

3. next question is for 32 or 16 bit mode the multiplication factor is 0.5 (higher than the 0.25 for 8 bits) makes the endurance more, so to write 16 or 32 bits on EEE does there any configuration? or I just have to access the location with respective type of pointers???

4. next question is, when FlexRAM is partitioned for EEE the unused portion can never be used in future? If No, How we can configure that? (because as stated in the 2nd point, it is visible that to keep the EEE as low as possible, so will it make the rest of FlexRAM unusable for the lifetime??)

5. one more question is endurance cycles derived from the equation are for one location only or whole subsystem?? does EEE uses only one subsystem or it switches internally (coz subsytem A endurance is dependant on the partition factor)

That's it for now...

Thanks and regards,

P

[jeremyzhou]

Hi

Please check answers.

1. from that equation I was able to conclude that if I use minimum FlexRAM for EEE and whole FlexNVM as E-flash I get the max endurance keeping partition factor 1/8 (which is the division factor only that comparitively makes the endurance higher than 1/2 or 1/4)...so lets say for my 5 KB of data, can I keep the EEE 32 bytes (which is the possible minimum)???

——Regarding to the quesiton, 32 Kb is ok, the partition factor should be configured by 1/4 to make the smaller subsystem also can store the the 5 KB of data.

2. next question is for 32 or 16 bit mode the multiplication factor is 0.5 (higher than the 0.25 for 8 bits) makes the endurance more, so to write 16 or 32 bits on EEE does there any configuration? or I just have to access the location with respective type of pointers???

——Yes

3. next question is, when FlexRAM is partitioned for EEE the unused portion can never be used in future? If No, How we can configure that? (because as stated in the 2nd point, it is visible that to keep the EEE as low as possible, so will it make the rest of FlexRAM unusable for the lifetime??)

——No, the rest of the FlexRAM can't be used for any other purposes.

4. one more question is endurance cycles derived from the equation are for one location only or whole subsystem?? does EEE uses only one subsystem or it switches internally (coz subsytem A endurance is dependant on the partition factor)

——For one location

Have a great day,

Ping

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[preetmehta]

Hi,

Thanks for the quick response. Can you please elaborate some of the answers I found confusing (The underlined ones)?

1. from that equation I was able to conclude that if I use minimum FlexRAM for EEE and whole FlexNVM as E-flash I get the max endurance keeping partition factor 1/8 (which is the division factor only that comparitively makes the endurance higher than 1/2 or 1/4)...so lets say for my 5 KB of data, can I keep the EEE 32 bytes (which is the possible minimum)???

——Regarding to the quesiton, 32 Kb is ok, the partition factor should be configured by 1/4 to make the smaller subsystem also can store the the 5 KB of data. (So here do you mean to say that though I make a subsystem of 4 / 4 = 1 Kbytes, I would be able to store 5KB in using that? like FlexRAM will store that 1 KB into record and again it will store my further data??? this way?)

2. next question is for 32 or 16 bit mode the multiplication factor is 0.5 (higher than the 0.25 for 8 bits) makes the endurance more, so to write 16 or 32 bits on EEE does there any configuration? or I just have to access the location with respective type of pointers???

——Yes (Yes for configuration or pointers?)

3. next question is, when FlexRAM is partitioned for EEE the unused portion can never be used in future? If No, How we can configure that? (because as stated in the 2nd point, it is visible that to keep the EEE as low as possible, so will it make the rest of FlexRAM unusable for the lifetime??)

——No, the rest of the FlexRAM can't be used for any other purposes.(for lifetime?)

4. one more question is endurance cycles derived from the equation are for one location only or whole subsystem?? does EEE uses only one subsystem or it switches internally (coz subsytem A endurance is dependant on the partition factor)

——For one location

Thanks,

P

[jeremyzhou]

Hi,

1. After had a look through your question again, the size of system data is 5 KB, as you mentioned above, so I'd like to suggest that you can configure the EEPROM with 8 KB size, the partition factor is 1/2, then the 5KB system data can be stored in the EEPROM

2. Just use the pointer is ok.

3. Once you do a partition if you decide to enable EEPROM functionality,  the reset of area is reserved and can't be used as traditional RAM forever.

Have a great day,

Ping

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Note: If this post answers your question, please click the Correct Answer button. Thank you!
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