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???
04/12/11 22:41
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 		 #181835 - Table bytes comparison
Responding to: ???'s previous message
In the 8051 mcu there are different memory areas, each one having their own addressing modes. http://www.8052.com/tutaddr.phtml#External%20Indirect

If both tables are located in code memory you can use the DPTR (16bit) register to get each byte and compare with the other table one-by-one.

If a table is located in iRam you can use the mov A, @R0

If a table is located in pData you can use the movx A, @R0

If a table is located in xData you can use the movx A, @DPTR

If a table is located in Code memory you can use the movc A, @A+DPTR

Some chips have 2 DPTR(s), making easier a task like this comparison.
The tables you showed so far have fixed lentgh of 25bytes.
Using C language as a method to program the 8051, functions from the standard C library are usefull to have this work(compare) done.



List of 77 messages in thread
TopicAuthorDate
Intel 8051 RS-232 Interface and fingerprint module !!            01/01/70 00:00      
   I want to see the packet            01/01/70 00:00      
   Comments            01/01/70 00:00      
      MTS-51 8051 Microcomputer Trainer            01/01/70 00:00      
         A what?            01/01/70 00:00      
            please help !!            01/01/70 00:00      
               Never wait until "it works"            01/01/70 00:00      
                  I do it            01/01/70 00:00      
                     RE: "must work to continue writing code"            01/01/70 00:00      
                     you got a very positive reply            01/01/70 00:00      
               You need to provide the information!            01/01/70 00:00      
               P2            01/01/70 00:00      
   that old?            01/01/70 00:00      
      No - not that old!            01/01/70 00:00      
         80C51RD+            01/01/70 00:00      
            But what about those displays??            01/01/70 00:00      
               7-Segment LED displays            01/01/70 00:00      
                  That raises further questions            01/01/70 00:00      
                     BCD to 7-segment decoder            01/01/70 00:00      
                        But still no answer - repeated identical values?            01/01/70 00:00      
                           DELAY            01/01/70 00:00      
                              And you're surprised that you miss characters?!            01/01/70 00:00      
                                 Yes you are right but            01/01/70 00:00      
                                    Think about it            01/01/70 00:00      
                                       too busy to think ?            01/01/70 00:00      
                                          Coding is the LAST thing you should do!            01/01/70 00:00      
   Interesting article about fingerprint recognition            01/01/70 00:00      
      Thank you very much            01/01/70 00:00      
         Nothing to do with nitgen            01/01/70 00:00      
            yes I have read...            01/01/70 00:00      
               Again,            01/01/70 00:00      
                  ok, I am listenig to you..            01/01/70 00:00      
                     Serial Comms            01/01/70 00:00      
                        Σας ευχαριστώ κύριε Αγγελή για την            01/01/70 00:00      
                           BEFORE you start coding...            01/01/70 00:00      
                           Thinking before coding            01/01/70 00:00      
   Thank you very much..            01/01/70 00:00      
      Standard byte-by-byte loop            01/01/70 00:00      
         is this ok ?            01/01/70 00:00      
            Table bytes comparison            01/01/70 00:00      
               Does 8051 has two DPTR ??            01/01/70 00:00      
                  Same DPTR if you don't have two            01/01/70 00:00      
                  Please crarify settings of board/device            01/01/70 00:00      
                     for the moment...            01/01/70 00:00      
                  WHY ON EARTH            01/01/70 00:00      
                     Yes I know what they are...            01/01/70 00:00      
                        Why even keep the received data in an array?            01/01/70 00:00      
                           Please read....            01/01/70 00:00      
                              I have - have you?            01/01/70 00:00      
                                 Yes please            01/01/70 00:00      
                                    you can't store in code memory            01/01/70 00:00      
   Is this code ok ??            01/01/70 00:00      
      Wrong focus for comments - and untested code            01/01/70 00:00      
         I have tested !!            01/01/70 00:00      
            do you have that much external RAM?            01/01/70 00:00      
            No. You think you have tested but not multiple turns            01/01/70 00:00      
            Experimenting with 8051 embedded            01/01/70 00:00      
               thank you...            01/01/70 00:00      
                  Here we are again....            01/01/70 00:00      
                     take a look !!            01/01/70 00:00      
                        Baudrate            01/01/70 00:00      
                           thanks            01/01/70 00:00      
                           yes, but better            01/01/70 00:00      
                              Question            01/01/70 00:00      
                                 difference between ORG 000H and ORG 113H            01/01/70 00:00      
                                    usually.....            01/01/70 00:00      
                                       Now do you understand...            01/01/70 00:00      
                                 ORG is not an instruction, it is ...            01/01/70 00:00      
                                    PLEASE SEE THIS AND HELP !!            01/01/70 00:00      
                                       Copied "END" without first reading what it meant?            01/01/70 00:00      
                                       step-by-step mode            01/01/70 00:00      
                                          thank you            01/01/70 00:00      
                                             Assembler way is difficult            01/01/70 00:00      
                                                Thank you.....            01/01/70 00:00      
                                                   Step through the examples            01/01/70 00:00      
                                                      Of course            01/01/70 00:00      
                                                         THANK YOU ALL            01/01/70 00:00      

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