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07/23/05 05:36
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#97857 - 8255 interfacing problem
I want to interface 8052 with 22MHz crystall with 8255.I have to do the following things
1. configuring 8255 portA as output, portB as input, portC as output.
2. display aah at portA and 55h at portC

below is the code I have written

org 00h

; This block of code is to configure 8255
setb 8255_RD
clr 8255_CS
setb 8255_a0
setb 8255_a1
mov p0,#082h
clr 8255_WR
setb 8255_WR
setb 8255_CS

; display aah at portA
clr 8255_a0
clr 8255_a1
mov p0,#0aah
clr 8255_WR
setb 8255_WR
setb 8255_CS

; display 55h at portC
clr 8255_a0
setb 8255_a1
mov p0,#055h
clr 8255_WR
setb 8255_WR
setb 8255_CS
sjmp$

Can any body suggest the problem with the above code...

My advance thanks to everybody...



List of 39 messages in thread
TopicAuthorDate
8255 interfacing problem            01/01/70 00:00      
   well..            01/01/70 00:00      
      8255 interface problem            01/01/70 00:00      
         If you must use 8255            01/01/70 00:00      
            My datasheet says.....            01/01/70 00:00      
   Settle Erik!            01/01/70 00:00      
      8255 problem            01/01/70 00:00      
         hardware            01/01/70 00:00      
            adding to Steve..            01/01/70 00:00      
            Comment            01/01/70 00:00      
               Relic            01/01/70 00:00      
                  that was not 8255            01/01/70 00:00      
                     Actually....            01/01/70 00:00      
                        ot: 825x in PC            01/01/70 00:00      
                           Parallel port            01/01/70 00:00      
                              NOoooooooooooooooooooo            01/01/70 00:00      
                                 Ooops            01/01/70 00:00      
                                    OK I give it up! :-)            01/01/70 00:00      
                                       Just like            01/01/70 00:00      
                                 8255 in original PC            01/01/70 00:00      
               If I did not keep up with the times and            01/01/70 00:00      
                  Do your kids drive Segway?            01/01/70 00:00      
                     the real problem is not that the 82xx is            01/01/70 00:00      
                        Erik - A history lesson            01/01/70 00:00      
                           ok, even further back            01/01/70 00:00      
                              Picky, picky            01/01/70 00:00      
                                 are we getting there now?            01/01/70 00:00      
                                    Oh altight then :-)            01/01/70 00:00      
         More info needed            01/01/70 00:00      
   Pull up resistors.            01/01/70 00:00      
      Pullups            01/01/70 00:00      
   no can do            01/01/70 00:00      
      Yes he can!            01/01/70 00:00      
         does not make it current            01/01/70 00:00      
            my opinion...            01/01/70 00:00      
               did you not read            01/01/70 00:00      
                  Nope            01/01/70 00:00      
   8255 PROBLEM            01/01/70 00:00      
      10 Points            01/01/70 00:00      

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