> > I am going to make a dictionary machine applying PIC micro. I plan
> > to use Micro-p + LCD + EEPROM. But I don't know  how to arrange
> > effectively storage structure of data of word and its explanation in
> > EEPROM. Anyone could shed light on it?


It really depends whether you need to compress new
data with the PIC. This will be difficult and slow
using eeprom due to the time accessing it and the
recursive nature of compression techniques. And
the limited multiplication/division ability if PICs.

It will be MUCH faster if you can just store the
already-compressed data in the eeprom, then use a
lookup table of the most common strings.

Since you only need about 26+26+10+15 =77
actual characters for text, each byte can have
have another 179 symbols.

Assuming you compress the text on your PC, you
scan through all the text and find the most
common 179 strings. like _and is a four letter
string and _the is a four letter string that
also fits on the front of many words. Not just
compile the 179 most common strings, but you need to
choose them by weighting, ie length x freq

ie:
_common (7 chars, occurs 30 times)
so 7x30 goes to 30 symbols = 180 saved

_and (4 chars, occurs 50 times)
so 4x50 goes to 50 symbols = 150 saved

So even though _and occurs more often, the
_common string would save more total bytes and
needs to be weighted higher in your final
selection of the 179 symbols you will use.
Solway covers this quite well in his "Bigtext"
software. This byte-symbol system is very fast
to decompress (perfect for PIC) and can offer
excellent compression.
-Roman

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