Hi,

Does anybody has experience using the msp430F149 as a datalogger, using 
a sequential flash segments erase and write method within a reserved 
16kb flash section (0xB000-0xF000). My concern is the broad-range flash 
write/erase cycle specification: nominal 100k, but minimal 10k. How 
realiable is the nominal 100k cycle parameter for field operation, 
i.e., how many devices are to be expected to start disfunction after 
10k write/erase cycles? 

Thanks,
Nico

I would design for the minimum of 10k cycles.  However, if it is a very
cost sensitive project there are some things that can be done.  Most of
these involve writing to flash less often.  There are risks that you
need to keep in mind though.  It also depends what you need to log and
how often things happen.  

Dan M

-----Original Message-----
From: msp430@msp4... [mailto:msp430@msp4...] On Behalf
Of njmarends
Sent: Thursday, May 05, 2005 4:55 AM
To: msp430@msp4...
Subject: [msp430] flash write/erase cycles

Hi,

Does anybody has experience using the msp430F149 as a datalogger, using 
a sequential flash segments erase and write method within a reserved 
16kb flash section (0xB000-0xF000). My concern is the broad-range flash 
write/erase cycle specification: nominal 100k, but minimal 10k. How 
realiable is the nominal 100k cycle parameter for field operation, 
i.e., how many devices are to be expected to start disfunction after 
10k write/erase cycles? 

Thanks,
Nico






.

 
Yahoo! Groups Links



 

I keep my supply voltage above 3V0 when writing flash. I keep Fclk 
within the publsihed spec (actually about 400kHz normally). I use word 
write. I execute from flash, ie no block write. I implement a mini flash 
file system when using just a limited amount of memory as a data store, 
typically I allocate 1 bit per word, or 1 segment, and store addresses 
of faulty words. I verify each write, and retry the write up to 3 times 
with a delay in between each attempt. In my experience, and I have 
tested this very extensively, I would personally consider the 100k limit 
to be conservative within the bondaries I described. using the failed 
word table method to log an absolute failure, and a second table to log 
those addresses that needed a 'second hit' over more than 100k write 
cycles the incidence of re-write attempts was less than 64 total, and 
there was 1 absolute failure which I attributed to some other factor at 
the time, as it later 'recovered'

Al

njmarends wrote:

>Hi,
>
>Does anybody has experience using the msp430F149 as a datalogger, using 
>a sequential flash segments erase and write method within a reserved 
>16kb flash section (0xB000-0xF000). My concern is the broad-range flash 
>write/erase cycle specification: nominal 100k, but minimal 10k. How 
>realiable is the nominal 100k cycle parameter for field operation, 
>i.e., how many devices are to be expected to start disfunction after 
>10k write/erase cycles? 
>
>Thanks,
>Nico
>
>
>
>
>
>
>.
>
> 
>Yahoo! Groups Links
>
>
>
> 
>
>
>
>
>  
>

You can increase flash endurance (probably) by:
- operating at lower temperatures (below 50degC)
- use verify after write, and mark/skip defective cells
  (I guess most cells survive 100k, but only a few just 10k).
- write seldom (use RAM cache and write on power fail, if possible)

Matthias

On Thu, May 05, 2005 at 09:55:04AM -0000, njmarends
wrote:
> Hi,
> 
> Does anybody has experience using the msp430F149 as a datalogger, using 
> a sequential flash segments erase and write method within a reserved 
> 16kb flash section (0xB000-0xF000). My concern is the broad-range flash 
> write/erase cycle specification: nominal 100k, but minimal 10k. How 
> realiable is the nominal 100k cycle parameter for field operation, 
> i.e., how many devices are to be expected to start disfunction after 
> 10k write/erase cycles? 
> 
> Thanks,
> Nico
> 
> 
> 
> 
> 
> 
> .
> 
>  
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
        Matthias

> Does anybody has experience using the msp430F149 as a datalogger,
using 
> a sequential flash segments erase and write method
within a reserved 
> 16kb flash section (0xB000-0xF000). My concern is the broad-range flash 
> write/erase cycle specification: nominal 100k, but minimal 10k. How 
> realiable is the nominal 100k cycle parameter for field operation, 
> i.e., how many devices are to be expected to start disfunction after 
> 10k write/erase cycles? 

My tests on a variety of Flash devices show that the write time stays
reasonably constant but the erase time gets longer. On average, above the
quoted cycle limit, the erase time pushes the erase/write cycle time above
the spec'ed time. The erase time increases exponentially. NOR flash was
shown not to have any bit errors when tested to 3 to 10 times the quote
cycle time (100k in the most part). NAND flash did show a slight increase
in bit failure, but then it has bit failure as part of normal operations.

Tests done 2 years ago with 32MByte to 512MByte devices

I can't tell you how it was done, nor for whom, why or what devices.

I doubt the MSP flash is any different from stand alone flash devices as it
is mostly a facet of the technologies.

Veronica




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