parallel flash,can read,can erase,can have deviceId but i can't write

Hi ,begging some help once more..

I'm interested in doing some little experience with parallel flash memories

i built a board to program ato parallel port of the pc,a CPLD is used as latch-I/O expander ,i wrote a program that allows me to control every single pin of the flash and to generate the sequences needed to perform various operations( always in BYTE mode) The flash i use is a M29W160DT by ST Microelectronics,i scraped it from some broken printer,or maybe DVD player ; having a programmed flash is useful to verify the correctness of the reading,i can read the strings of characters like "Copyright 2004-2005" and so on; looks odd that the chars of the strings appears inverted (i.e. "Fred" looks like "rFde"),doees Little Endian applies to strings too???

I implemented such kind of sequences as told in the datasheet

Chip Erase AAA AA 555 55 AAA 80 AAA AA 555 55 AAA 10

and it works:performing some readings shows that the entire memory is now at 0xFF

Program AAA AA 555 55 AAA A0 PA PD

for every pair address-data:

i prepare address and data, then CE goes LOW, then WR goes low to latch the address then WR goes HIGh to latch the Data Then CE goes HIGH

Please can you tell me where errors are? Many thanks

Diego, Milan, Italy

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