Has someone used the flash memory of the lpc21xx for eeprom purposes?
Or is it more usefull to take an additive eeprom to the design? I only
want to store some parameters.
Thank you for feedback!
Martin
Re: Using flash memory instead of eeprom? Re: Using flash memory instead of
eeprom? Re: Using flash memory instead of eeprom? Re: Using flash
memory instead of eeprom? Re: Using flash memory instead of eeprom? Re: Using flash memory instead of eeprom? Re: Using flash memory instead
of eeprom? Re: Using flash memory instead of eeprom? Re: Using flash
memory instead of eeprom?
Reply by Rajkumar Shetgar RBIN/ECR2●January 31, 20052005-01-31
Hi,
Its always better to have EEPROM if you have frequent write cycles.
Flash used for code memory has roughly around 1000 write cycles, where
as if its data flash it has around 10,000+ write cycles. And EEPROM has
around 1 million write cycles.
Regards,
Raj
_____
From: gewitter2000 [mailto:]
Sent: Monday, 31. January 2005 6:43 PM
To:
Subject: [lpc2000] Using flash memory instead of eeprom?
Hi!
Has someone used the flash memory of the lpc21xx for eeprom purposes?
Or is it more usefull to take an additive eeprom to the design? I only
want to store some parameters.
Thank you for feedback!
Martin
_____
> .
Re: Using flash memory instead of eeprom?
Reply by ntfreak2000●January 31, 20052005-01-31
--- In , "Rajkumar Shetgar (RBIN/ECR2)"
<Rajkumar.Shetgar@i...> wrote: > Hi,
>
> Its always better to have EEPROM if you have frequent write cycles. > Flash used for code memory has roughly around 1000
write cycles, where > as if its data flash it has around 10,000+ write
cycles. And EEPROM has > around 1 million write cycles.
>
> Regards,
> Raj
>
> _____
>
> From: gewitter2000 [mailto:martin@c...]
> Sent: Monday, 31. January 2005 6:43 PM
> To:
> Subject: [lpc2000] Using flash memory instead of eeprom?
>
> Hi!
>
> Has someone used the flash memory of the lpc21xx for eeprom purposes? > Or is it more usefull to take an additive eeprom
to the design? I only > want to store some parameters.
>
> Thank you for feedback!
> Martin
> _____
>
> > .
I have used this technique with the ST STR7 devices, they have a
write cycle of 100,000 and if combined with a linked list type
structure to minimise using the same blocks it is a cheap method of
eeprom emulation.
Regards
sjo
Reply by Richard●January 31, 20052005-01-31
There are many serial flash devices (I Use SST25vf512)that guarantee
100K cycles and 100 years. Flash offers byte write and sector erase,
while EEPROM offers both byte write and erase but are SLOW.
Richard
--- In , "gewitter2000" <martin@c...> wrote: >
> Hi!
>
> Has someone used the flash memory of the lpc21xx for eeprom purposes?
> Or is it more usefull to take an additive eeprom to the design? I only
> want to store some parameters.
>
> Thank you for feedback!
> Martin
Re: Using flash memory instead of eeprom? Re: Using flash memory instead of
eeprom? Re: Using flash memory instead of eeprom? Re: Using flash
memory instead of eeprom? Re: Using flash memory instead of eeprom?
Reply by Robert Wood●January 31, 20052005-01-31
Serial FRAM is available and not too outrageously priced now. Not as cheap
as
EEPROM, but if your project isn't cost sensitive it works a treat and you
have unlimited life non-volatile memory.
--------------------------
There are many serial flash devices (I Use SST25vf512)that guarantee
100K cycles and 100 years. Flash offers byte write and sector erase,
while EEPROM offers both byte write and erase but are SLOW.
Richard
--- In , "gewitter2000" <martin@c...> wrote: >
> Hi!
>
> Has someone used the flash memory of the lpc21xx for eeprom purposes?
> Or is it more usefull to take an additive eeprom to the design? I only
> want to store some parameters.
>
> Thank you for feedback!
> Martin
Yahoo! Groups Links
Re: Using flash memory instead of eeprom? Re: Using flash memory instead of
eeprom? Re: Using flash memory instead of eeprom? Re: Using flash
memory instead of eeprom?
Reply by Owen Mooney●January 31, 20052005-01-31
Yes I have. Its easy, but you have to use up a whole page (unless you read -
modify - write) I had lots of spare flash and was typically saving a
configuration just a few times so these limitations didn't matter.
Code using IAP instructions below.
Accessing the stored structure is just a direct memory access.
The write cycle limitations have been well documented by those willing to offer
an opinion but not answer your question !!!
Owen Mooney
#define IAP_LOCATION 0x7ffffff1
void savesetup(struct SETUP *setup){
typedef void (*IAP)(unsigned int [],unsigned int[]);
unsigned int command[5];
unsigned int result[2];
IAP iap_entry;
__ARMLIB_disableIRQ();
iap_entry=(IAP) IAP_LOCATION;
// get part ID
command[0]T;
result[0]=0;
iap_entry(command, result);
// result in result[1]
// prepare to erase
command[0]P;
command[1];
command[2];
iap_entry(command, result);
if (result[0] != 0) goto error;
// erase
command[0]R;
command[1];
command[2];
command[3]745;
iap_entry(command, result);
if (result[0] != 0) goto error;
// prepare to program
iap_entry=(IAP) IAP_LOCATION;
command[0]P;
command[1];
command[2];
iap_entry(command, result);
if (result[0] != 0) goto error;
// program
command[0]Q;
command[1]=0x1C000;
command[2]=(int)setup;
command[3]Q2;
command[4]745;
iap_entry(command, result);
if (result[0] != 0) goto error;
__ARMLIB_enableIRQ();
return;
error:
__ARMLIB_enableIRQ();
printf("bum");
}
Hi!
Has someone used the flash memory of the lpc21xx for eeprom purposes?
Or is it more usefull to take an additive eeprom to the design? I only
want to store some parameters.
Thank you for feedback!
Martin
____________
Re: Subject: Using flash memory instead of eeprom? Re: Subject: Using flash
memory instead of eeprom?
Reply by embeddedjanitor●February 1, 20052005-02-01
AFAIK FRAM does not have unlimited life. It was around 10^6 cycles
when I forst looked at it many years back and I believe it is now
around 10^12 cycles, compared to around 10^5 cycles for EEPROM and
flash.
The smallprint though is that for EEPROM and flash, the endurance
counts only the write cycles and not read cycles whereas FRAM
endurance counts both.
Because it is "just like RAM" once might be tempted to try place
variables in FRAM or data items that you read frequently (data as
well as code). In this case you could hit that 10^12 cycles pretty
fast. With worst case code on an LPCxxx style device you could end up
hitting the FRAM for more than 10^7 cycles per second, giving only a
useful life of 10^5 seconds or just over a day.
As always, design with your eyes open!
--- In , Robert Wood <robert.wood@a...> wrote: > Serial FRAM is available and not too outrageously
priced now. Not as cheap as > EEPROM, but if your project isn't cost
sensitive it works a treat and you > have unlimited life non-volatile memory.
>
> --------------------------
>
> There are many serial flash devices (I Use SST25vf512)that guarantee
> 100K cycles and 100 years. Flash offers byte write and sector erase, > while EEPROM offers both byte write and erase but
are SLOW.
>
> Richard
>
> --- In , "gewitter2000" <martin@c...> wrote:
> >
> > Hi!
> >
> > Has someone used the flash memory of the lpc21xx for eeprom purposes? > > Or is it more usefull to take an additive
eeprom to the design? I only > > want to store some parameters.
> >
> > Thank you for feedback!
> > Martin
>
> Yahoo! Groups Links
Re: Using flash memory instead of eeprom? Re: Using flash memory instead of
eeprom? Re: Using flash memory instead of eeprom?
Reply by Varuzhan Danielyan●February 1, 20052005-02-01
Dear embeddedjanitor,
Please, open your eyes and have a look to www.ramtron.com. You will see, that
many
of their FRAMs now have not any write/read cycles limiting!
Varuzhan
----- Original Message -----
From: embeddedjanitor
To:
Sent: Tuesday, February 01, 2005 8:25 AM
Subject: [lpc2000] Re: Using flash memory instead of eeprom?
AFAIK FRAM does not have unlimited life. It was around 10^6 cycles
when I forst looked at it many years back and I believe it is now
around 10^12 cycles, compared to around 10^5 cycles for EEPROM and
flash.
The smallprint though is that for EEPROM and flash, the endurance
counts only the write cycles and not read cycles whereas FRAM
endurance counts both.
Because it is "just like RAM" once might be tempted to try place
variables in FRAM or data items that you read frequently (data as
well as code). In this case you could hit that 10^12 cycles pretty
fast. With worst case code on an LPCxxx style device you could end up
hitting the FRAM for more than 10^7 cycles per second, giving only a
useful life of 10^5 seconds or just over a day.
As always, design with your eyes open!
--- In , Robert Wood <robert.wood@a...> wrote: > Serial FRAM is available and not too outrageously
priced now. Not as cheap as > EEPROM, but if your project isn't cost
sensitive it works a treat and you > have unlimited life non-volatile memory.
>
> --------------------------
>
> There are many serial flash devices (I Use SST25vf512)that guarantee
> 100K cycles and 100 years. Flash offers byte write and sector erase, > while EEPROM offers both byte write and erase but
are SLOW.
>
> Richard
>
> --- In , "gewitter2000" <martin@c...> wrote:
> >
> > Hi!
> >
> > Has someone used the flash memory of the lpc21xx for eeprom purposes? > > Or is it more usefull to take an additive
eeprom to the design? I only > > want to store some parameters.
> >
> > Thank you for feedback!
> > Martin
>
> Yahoo! Groups Links
------
Yahoo! Groups Links
a.. To
Reply by Robert Adsett●February 1, 20052005-02-01
At 04:25 AM 2/1/05 +0000, embeddedjanitor wrote: >AFAIK FRAM does not have unlimited life. It was
around 10^6 cycles
>when I forst looked at it many years back and I believe it is now
>around 10^12 cycles, compared to around 10^5 cycles for EEPROM and
>flash.
They rate the low voltage devices as unlimited read/write cycles (I just
re-checked). As I recall, it is only within the last couple of years that
devices rated for that have been available. The high voltage (5V) devices
range from 10^10 to 10^12 read/write cycles. The write speed of FRAM
compared to ee is certainly an advantage but I wouldn't want to put a
millisecond clock in an older device.
Robert
" 'Freedom' has no meaning of itself. There are always
restrictions,
be they legal, genetic, or physical. If you don't believe me, try to
chew a radio signal. "
Kelvin Throop, III
Reply by 42Bastian Schick●February 1, 20052005-02-01
> Because it is "just like RAM" once might be tempted to try
place > variables in FRAM or data items that you read
frequently (data as
> well as code). In this case you could hit that 10^12 cycles pretty
> fast. With worst case code on an LPCxxx style device you could end up
> hitting the FRAM for more than 10^7 cycles per second, giving only a
> useful life of 10^5 seconds or just over a day.
Not quiet right. I just looked up on datasheet at Ramtron.
The max. bus-freq. is 1E6 Hz for a 256KB FRAM.
20bits to read memory => max. 50000 reads/s
The chip I look at has an endurance of 1E10, gives 200.000s ~= 138d.
Also not forever, but slightly longer :-)
> As always, design with your eyes open! Anyway a good hint :-)
