Lpc2000

Does anyone know if it is allowed to program the same 512 byte sector 
multiple times (assuming that with each call bits only get cleared 
not set)?

I currently have my RAM 512 byte buffer filled with 0xFF and write a 
string to the first 16 bytes, and program that into Flash (writing 
all 512 bytes).

Works fine.

Next step I am only modifying bytes 16 to 31 (which were 0xFF before) 
and try to write again to the same destination address. The call to 
write flash produces no error, however, if I read back from Flash I 
see that one of my just added bytes does not have the right value, 
one bit too many got changed from one to zero. I see a 't' (in flash) 
instead of a 'u' (which is in RAM).

I tried different addresses to verify that it is really not the Flash 
memory, and yes, it happens also if I use a different address - same 
bit.

Thanks,

Peter

Peter,

The following post contains answers to your questions

http://groups.yahoo.com/group/lpc2000/message/2681

Philips Apps

--- In lpc2000@yahoogroups.com, "embeddednut" <embeddednut@y...> 
wrote:
> 
> Does anyone know if it is allowed to program the same 512 byte 
sector 
> multiple times (assuming that with each call bits only get cleared 
> not set)?
> 
> I currently have my RAM 512 byte buffer filled with 0xFF and write 
a 
> string to the first 16 bytes, and program that into Flash (writing 
> all 512 bytes).
> 
> Works fine.
> 
> Next step I am only modifying bytes 16 to 31 (which were 0xFF 
before) 
> and try to write again to the same destination address. The call to 
> write flash produces no error, however, if I read back from Flash I 
> see that one of my just added bytes does not have the right value, 
> one bit too many got changed from one to zero. I see a 't' (in 
flash) 
> instead of a 'u' (which is in RAM).
> 
> I tried different addresses to verify that it is really not the 
Flash 
> memory, and yes, it happens also if I use a different address - 
same 

> bit.
> 
> Thanks,
> 
> Peter

On Friday 22 October 2004 02:12, embeddednut wrote:
> Does anyone know if it is allowed to program the same 512 byte sector
> multiple times (assuming that with each call bits only get cleared
> not set)?
>
> I currently have my RAM 512 byte buffer filled with 0xFF and write a
> string to the first 16 bytes, and program that into Flash (writing
> all 512 bytes).
>
> Works fine.
>
> Next step I am only modifying bytes 16 to 31 (which were 0xFF before)
> and try to write again to the same destination address. The call to
> write flash produces no error, however, if I read back from Flash I
> see that one of my just added bytes does not have the right value,
> one bit too many got changed from one to zero. I see a 't' (in flash)
> instead of a 'u' (which is in RAM).
>
> I tried different addresses to verify that it is really not the Flash
> memory, and yes, it happens also if I use a different address - same
> bit.
>
> Thanks,
>
> Peter

Partial page programming did not work for me either. I found that it 
sometimes works and sometimes corrupts. However the corruptions were enough 
that I could never get 128k to load successfully.

Eventually I just modified my loader to program in 512byte pages.

-- Charles

Are you sure you specified the CCLK value correctly in the IAP call?
I've had success so far with partial page updates (for tracking device
state variables for restoration across reboots).  Of course, I haven't
done exhaustive testing, yet, so maybe I've just been lucky. 
 
Just out of curiosity, can you give a sample dataset that causes this
(flash/ram addresses and data, as well as your clock values)?  I'd like
to verify this potential problem before we hit production...
 
Thanks,
 
--rich

-----Original Message-----
From: Charles Manning [mailto:manningc2@...] 
Sent: Thursday, October 21, 2004 5:49 PM
To: lpc2000@yahoogroups.com; embeddednut
Subject: Re: [lpc2000] LPC2129 Flash IAP "feature"
 
On Friday 22 October 2004 02:12, embeddednut wrote:
> Does anyone know if it is allowed to program the same 512 byte sector
> multiple times (assuming that with each call bits only get cleared
> not set)?
>
> I currently have my RAM 512 byte buffer filled with 0xFF and write a
> string to the first 16 bytes, and program that into Flash (writing
> all 512 bytes).
>
> Works fine.
>
> Next step I am only modifying bytes 16 to 31 (which were 0xFF before)
> and try to write again to the same destination address. The call to
> write flash produces no error, however, if I read back from Flash I
> see that one of my just added bytes does not have the right value,
> one bit too many got changed from one to zero. I see a 't' (in flash)
> instead of a 'u' (which is in RAM).
>
> I tried different addresses to verify that it is really not the Flash
> memory, and yes, it happens also if I use a different address - same
> bit.
>
> Thanks,
>
> Peter

Partial page programming did not work for me either. I found that it 
sometimes works and sometimes corrupts. However the corruptions were
enough 
that I could never get 128k to load successfully.

Eventually I just modified my loader to program in 512byte pages.

-- Charles



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