> The 29C040A does an automatic erase before write, so that's
> covered. It also has a small sector size of 256 bytes (2048 of
> them), which is about all you can load into an F877. As far as I
> can see, the smallest sector size in a "large" Flash memory is
> 64 bytes. It's a read-modify-write operation - you have to load the
> sector into the PIC, modify it and then write it back as a whole
> sector (AFAIK). Other Flash chips have very large sectors that
> need a separate SRAM to copy them into, and the erasure of
> those large sectors when writing back can take some time (many
> seconds), whereas small sectors can be modified in a few 10's
> of ms

I guess you have been reading too much of the ..A or 18F... Datasheets.
The 16f87* (without A!) can write a single instruction (14 bits) at a
time.

Wouter van Ooijen

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