Lpc2000

I understand the various limitations concering the internal flash 
memory.  Concering the 16 writes per 4096 bit block limitation, I am 
doing 32 128-bit writes without problems.  What is the potential 
danger of doing this?

Thanks,

JT

John,

the answer is simple, unreliable data :-( A new device will probably 
not show any proplems but over time data retention will get worse and 
you could simply loose data. Could work for quite a while but 
absolutely not recommended (and not specified). 

Robert

--- In lpc2000@yahoogroups.com, "johnthomasedwardtimm" <area51@a...> 
wrote:

> 
> I understand the various limitations concering the internal flash 
> memory.  Concering the 16 writes per 4096 bit block limitation, I am 
> doing 32 128-bit writes without problems.  What is the potential 
> danger of doing this?
> 
> Thanks,
> 
> JT

Robert,

Thanks for the reply.  Can I write 32 byte (256-bit) chunks 16 times 
to fill a 4096-bit section?  I believe in a previous email you 
mentioned that 256-bit is the maximum size of a chunk you can write 
to a 4096-bit row that has data in it already.

Thanks,

JT

--- In lpc2000@yahoogroups.com, "philips_apps" <philips_apps@y...> 
wrote:
> 
> John,
> 
> the answer is simple, unreliable data :-( A new device will 
probably 
> not show any proplems but over time data retention will get worse 
and 
> you could simply loose data. Could work for quite a while but 
> absolutely not recommended (and not specified). 
> 
> Robert
> 
> --- In lpc2000@yahoogroups.com, "johnthomasedwardtimm" 
<area51@a...> 
> wrote:
> > 
> > I understand the various limitations concering the internal 
flash 
> > memory.  Concering the 16 writes per 4096 bit block limitation, 
I am 

> > doing 32 128-bit writes without problems.  What is the potential 
> > danger of doing this?
> > 
> > Thanks,
> > 
> > JT

I definitely got problems when writing 64 or 32 byte chunks on an 
LPC2129. After some experimentation I found I could only get reliable 
behaviour with 512 bytes (didn't test bigger).

Typically, I'd see a few wrong bits out of 64kB. This might have been 
fixed in a more recent bootloader.





--- In lpc2000@yahoogroups.com, "johnthomasedwardtimm" <area51@a...> 
wrote:

> 
> Robert,
> 
> Thanks for the reply.  Can I write 32 byte (256-bit) chunks 16 times 
> to fill a 4096-bit section?  I believe in a previous email you 
> mentioned that 256-bit is the maximum size of a chunk you can write 
> to a 4096-bit row that has data in it already.
> 
> Thanks,
> 
> JT
> 
> --- In lpc2000@yahoogroups.com, "philips_apps" <philips_apps@y...> 
> wrote:
> > 
> > John,
> > 
> > the answer is simple, unreliable data :-( A new device will 
> probably 
> > not show any proplems but over time data retention will get worse 
> and 
> > you could simply loose data. Could work for quite a while but 
> > absolutely not recommended (and not specified). 
> > 
> > Robert
> > 
> > --- In lpc2000@yahoogroups.com, "johnthomasedwardtimm" 
> <area51@a...> 
> > wrote:
> > > 
> > > I understand the various limitations concering the internal 
> flash 
> > > memory.  Concering the 16 writes per 4096 bit block limitation, 
> I am 
> > > doing 32 128-bit writes without problems.  What is the potential 
> > > danger of doing this?
> > > 
> > > Thanks,
> > > 
> > > JT

Hi,

I also want to write small chunks to the same sector.

I'm using a '2294.  The users manual (table 216 in the IAP section of 
the May 3, 2004 manual and also the 'C' command in the ISP section) 
shows that the destination address must be 512 byte aligned and that 
the number of bytes to write is a multiple of 512 bytes.

I have tried writing smaller areas within the 512 byte "sectors" by 
leaving all unchanged bits set (i.e., prefill the RAM buffer with the 
0xFF and clear only the required bits.)  After struggling with this 
for some time I concluded that the ECC bytes (checks) are written to 
flash on a 512 byte boundary basis, regardless of the fact that there 
is an ECC byte for each 16-bytes of accessible flash.

In short, the internal flash does not behave like a conventional 
flash part.  I can program 512-byte blocks and I can erase sectors.  
In my experience, that's it.  


Tom



--- In lpc2000@yahoogroups.com, "embeddedjanitor" <manningc2@a...> 
wrote:
> 
> I definitely got problems when writing 64 or 32 byte chunks on an 
> LPC2129. After some experimentation I found I could only get 
reliable 
> behaviour with 512 bytes (didn't test bigger).
> 
> Typically, I'd see a few wrong bits out of 64kB. This might have 
been 
> fixed in a more recent bootloader.
> 
> 
> 
> 
> 
> --- In lpc2000@yahoogroups.com, "johnthomasedwardtimm" 
<area51@a...> 
> wrote:
> > 
> > Robert,
> > 
> > Thanks for the reply.  Can I write 32 byte (256-bit) chunks 16 
times 
> > to fill a 4096-bit section?  I believe in a previous email you 
> > mentioned that 256-bit is the maximum size of a chunk you can 
write 

> > to a 4096-bit row that has data in it already.
> > 
> > Thanks,
> > 
> > JT
> >