actually i solved my problem already, i've used the wrong chip for my mcu, i used 8255ac instead of 82c55a. thanks for the help anyway

i've got another problem. i need to link a LCD and a 4x4 keypad to the 8051, i've got one 8 port free on the MCU and 3 port free on the 8255 ppi, how do u think i should link the keypad and the lcd to the mcu. the keypad uses 8 pin and the lcd uses 11 pin