mehmet,

search on this site an i think you will find the '8255 has been discussed to some length both parametrically and practically.

two characteristics should be understood when using this part:

• it glitches with mode word updates (depending upon your hardware this may not be problem
• be aware of "tRV" timing (this period between falling edge of or /wr or /rd and the leading edge of the next falling edge).
  

regards,
p