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Page-mode EEPROM - may I write a singe byte?

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atferrari

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I am currently trying to use this page-mode EEPROM

http://www.sst.com/downloads/datasheet/S71062.pdf

Accoding to what I understood, every time a "write" order is issued, an internal Write Cycle executes the writing of a full page (128 bytes) with the contents of an internal buffer.

My questions:

a) While not explicitly said, it seems that I could write just one byte if desired. Am I wrong? If not, how should I do that?

b) During the byte load cycle, let's say that I pass a value of H'33' for the first ten bytes in the buffer. Will the rest of the buffer acquire a value of 0 or H'FF'?
After completing the writing, that page in the EEPROM would have the first ten bytes = H'33'. And the rest of that page?

c) Or it is that I must compulsory give the 128 values, even if they are 0s for the write cycle to proceed?

The write cycle flow diagram is ambiguous (at least for me) because it seems that I could write some of the bytes in the target page.

Anyone with experience on this modality?
 

Pommie

Well-Known Member
Most Helpful Member
I have not used that device but a similar (Atmel) device wrote 0xffs to any locations not explicitly written. Why not try it and see.

If you must change 1 byte then I think you have to read, modify and write the whole sector.

Mike.
 

atferrari

Well-Known Member
I will try

Why not try it and see.
Gracias for replying, Mike. Yes, it seems that I will have to make clear this by myself.

<Add> Just reread the datasheet and found:

During the internal Write cycle, the host is free to perform additional tasks, such as to fetch data from other locations in the system to set up the write to the next page. In each Page-Write operation, all the bytes that are loaded into the page buffer must have the same page address, i.e. A7 through A16. Any byte not loaded with user data will be written to FFH. </Add>
 
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