Help:embedded programming for 8051 using 8255

[logukalipal]

Help:embedded programming for 8051 using 8255?

I connected two 8255 ppi to 8051 to accessing keypad and lcd and other modules are connected in that.
I attached here my schematic diagram and embedded c programming for that.
while i simulating that i cant find out error.
Can anyone findout?

 

[jayanth.devarayanadurga]

Re: Help:embedded programming for 8051 using 8255?

Why are you controlling the 2nd 8255 by 1st 8255? Can't you connect the RD, WR, A0, A! lines of the two 8255's to 8051?

 

[logukalipal]

I not control the 2nd 8255 by 1st one.Just i connected keypad pins separately by that two 8255.
row pins connected 1st ppi.
column pins connected 1st ppi.
I check the column pins through port b of 2nd 8255.
But it does not work, its the problem..

Thanks in advance..