is a pic able to handle all this work?

[Jay2004]

I am thinking to design a hand-held terminal project, the function of this terminal is able to take the input from a keypad(4x4) then search data from the memory(eeprom) and display the result on a 2 or 4 lines LCD, input will be 4 digits number, the output will be 15 letters long, around 1000 data will be recorded. my question are:
what kind of eeprom can be used?
how to create a look-up table?
can i load the data from pc through a pic into eeprom?
am i doing the right way?

thanks!

Jay

[dbotkin]

Well, a 24LC256 should be sufficient. You might be able to get it down to a 24LC128. I'm figuring a layout with 2 bytes for the number, 15 for the data. 17 bytes x 1000 entries comes up to 17000 bytes, just a little too big for a 24LC128. A 24LC256 will give you enough room for 1927 entries.

Your 4-digit number can be anything from 0000 to 9999 (or FFFF?), which can be represented by two bytes. A lookup table would be ridiculously long, so just store the index with the data. Convert your 4 keystrokes to a long, look at EEPROM address 0 for a match on the high-order byte, if it matches see if address 1 matches the low-order byte. If so you fetch the next 15 locations as data. If there's no match just repeat the process, adding 17 (15 data plus 2 index) to the EEPROM address until you run out of address space. I've done something very similar with a 16F877 at 20 MHz and it's plenty fast. Matter of fact it may have been 4 MHz, but the limiting factor will be the EEPROM read speed.

You can load data from the PC into EEPROM, sure. Serial receive, write to EEPROM. Do it at a low enough baud rate with a hardware UART and you won't even need handshaking.

As for whether you're doing it right - it's too soon to tell! And to answer your question of whether the PIC can handle all the work... sure, but what will it be doing the other 90% of the time?

[jay2004]

Hi!dbotkin,
thanks for the help!!