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