flash post test
Hi all,
Currently I am testing the Flash memory by using "Write and Read the same pattern" method (Protecting the UBoot Flash Sectors).
Is it safer to test flash memory during bootup?what if power gets off during process?
I want to know whether there is any alternative method to test the complete FLASH MEMORY.
Hi vk,
Le 31/01/2012 10:27, vk a ?crit :
Quoted 11 lines
Hi all,
Currently I am testing the Flash memory by using "Write and Read the same pattern" method (Protecting the UBoot Flash Sectors).
Is it safer to test flash memory during bootup?what if power gets off during process?
I want to know whether there is any alternative method to test the complete FLASH MEMORY.
Do you mean that you want to test the flash by writing to it on every power-up? What is the point?
Amicalement,
Signature · 1 line
Albert.
hi albert
Yes,actually there is already support of flash test in POST of latest uboot.They are testing flash on every power on so am I for my board.But i don't want to disturb sectors in which uboot code relies. Can you help me here?
Quoted 25 lines · Albert ARIBAUD
Hi vk,
Le 31/01/2012 10:27, vk a ?crit :
Hi all,
Quoted 5 lines
Currently I am testing the Flash memory by using "Write and Read the same pattern" method (Protecting the UBoot Flash Sectors).
Quoted 7 lines
Is it safer to test flash memory during bootup?what if power gets off during
process?I want to know whether there is any alternative method to test the complete FLASH MEMORY.
Do you mean that you want to test the flash by writing to it on every power-up? What is the point?
Amicalement,
--
Albert.
Hi Vaibhav,
Le 06/02/2012 05:57, vaibhav kothari a ?crit :
Quoted 6 lines
hi albert
Yes,actually there is already support of flash test in POST of latest uboot.They are testing flash on every power on so am I for my board.But i don't want to disturb sectors in which uboot code relies. Can you help me here?
I am no NAND specialist, but I do hope NAND POST tests are pure read tests and thus are not affected by poweroffs (and can actually test any part of NAND).
Amicalement,
Signature · 1 line
Albert.
Quoted 5 lines · Albert ARIBAUD
Hi Vaibhav,
Le 06/02/2012 05:57, vaibhav kothari a ?crit :
Quoted 2 lines
hi albert
Quoted 8 lines
Quoted 4 lines
Yes,actually there is already support of flash test in POST of latest uboot.They are testing flash on every power on so am I for my board.But i don't want to disturb sectors in which uboot code relies. Can you help me here?
I am no NAND specialist, but I do hope NAND POST tests are pure read tests and thus are not affected by poweroffs (and can actually test any part of NAND).
NAND has a property called "read disturb", where excessively reading a sector without writing to it can eventually cause data loss. U-Boot is already read once per boot, but reading it a second time could halve the expected lifetime. Data managed by something like ubi is be scrubbed in a way that avoids this, but U-Boot itself is not usually managed in this way (boot hardware/rom does not understand ubi).
-Scott
Hi Scott,
Le 06/02/2012 23:55, Scott Wood a ?crit :
Quoted 15 lines · Albert ARIBAUD
Quoted 5 lines
Hi Vaibhav,
Le 06/02/2012 05:57, vaibhav kothari a ?crit :
Quoted 2 lines
hi albert
Quoted 8 lines
Quoted 4 lines
Yes,actually there is already support of flash test in POST of latest uboot.They are testing flash on every power on so am I for my board.But i don't want to disturb sectors in which uboot code relies. Can you help me here?
I am no NAND specialist, but I do hope NAND POST tests are pure read tests and thus are not affected by poweroffs (and can actually test any part of NAND).
Quoted 6 lines
NAND has a property called "read disturb", where excessively reading a sector without writing to it can eventually cause data loss. U-Boot is already read once per boot, but reading it a second time could halve the expected lifetime. Data managed by something like ubi is be scrubbed in a way that avoids this, but U-Boot itself is not usually managed in this way (boot hardware/rom does not understand ubi).
I *did* say I am not a NAND expert. :)
Thanks Scott. But then, isn't NAND testing a kind of catch-22, where by actually tesing if NAND works it one ends up weakening it either through read disturb, or simply through writes?
Quoted 1 line
-Scott
Amicalement,
Signature · 1 line
Albert.
Quoted 27 lines · Albert ARIBAUD
Hi Scott,
Le 06/02/2012 23:55, Scott Wood a ?crit :
Quoted 17 lines · Albert ARIBAUD
Quoted 12 lines
Hi Vaibhav,
Le 06/02/2012 05:57, vaibhav kothari a ?crit :
Quoted 8 lines
hi albert
Yes,actually there is already support of flash test in POST of latest uboot.They are testing flash on every power on so am I for my board.But i
don't want to disturb sectors in which uboot code relies. Can you help me
here?Quoted 3 lines
I am no NAND specialist, but I do hope NAND POST tests are pure read tests and thus are not affected by poweroffs (and can actually test any part of NAND).
Quoted 6 lines
NAND has a property called "read disturb", where excessively reading a sector without writing to it can eventually cause data loss. U-Boot is already read once per boot, but reading it a second time could halve the expected lifetime. Data managed by something like ubi is be scrubbed in a way that avoids this, but U-Boot itself is not usually managed in this way (boot hardware/rom does not understand ubi).
Quoted 5 lines
I *did* say I am not a NAND expert. :)
Thanks Scott. But then, isn't NAND testing a kind of catch-22, where by actually tesing if NAND works it one ends up weakening it either through read disturb, or simply through writes?
It's fine for occasional manual testing, or routine testing of an area that gets properly scrubbed.
-Scott
hi albert,Scott
Thnks for your reply.Other than uib ,is there any data pattern/algorithm for flash testing which effects less on lifespan of flash??