Hash functions

[Dwayne]

Hello Ioannis,

I>>Does anyone have any experience with Hash Functions to code the unique iButton serial number into a memory address to find it then instantly?<<

Ouch...Unless you can use a "function" to calculate your address directly, you are talking about time. Some Hashing routines use functions as such. The other Hash routines will probably require more time in calculating , then it would be to read the data and compare. How many items will you have?

Can you store them in a ASCII logical order and do a Binary Search routine?
This will limit your number of reads down. if you have 256 items (like in a table) you would find (worse case senario) 8 reads to have your value.

Dwayne

[Ioannis]

Thanks for the replies.

Well a 20 MHz xtal is not the best since speeding up to 5 times is not enough. There will be an incresing number of keys and may reach up to 300 or 400. Imagine a PIC searching 400 6-8 byte numbers!!!

The binary tree is a good option. Did not think about it.

Thanks again.

Ioannis