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???
09/21/07 07:27
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 		 #144868 - Modbus
Responding to: ???'s previous message
Modbus RTU or ASCII works well with either RS232 or RS485. Depending on what features you want to implement, Modbus RTS or ASCII should fit into the 4K code space of a 89S51 if you use assembler. I squeezed it into a 89C2051 (2k) and had room to spare.

www.modbus.org has the specifications
www.win-tech.com has programs to simulate and act as a master for modbus on your PC.

If you can make your data look like 16 bit registers or bits, Modbus will work well for you.

List of 46 messages in thread
TopicAuthorDate
MCS-51 and RS485            01/01/70 00:00      
   Specifics?            01/01/70 00:00      
   not enough clear            01/01/70 00:00      
   RS485 code at code library didn't work's            01/01/70 00:00      
   .ASM or .C code nevermind            01/01/70 00:00      
      But what do you need it to do?            01/01/70 00:00      
         485 master slave            01/01/70 00:00      
            I did            01/01/70 00:00      
               RS-485 master/slave code.            01/01/70 00:00      
                  Try Modbus            01/01/70 00:00      
                     Oops sorry,Must using uart with another mode.            01/01/70 00:00      
   RS-485 code            01/01/70 00:00      
      Full duplex?            01/01/70 00:00      
         Full duplex ...the reasons            01/01/70 00:00      
            That's not a reason!            01/01/70 00:00      
            Technically            01/01/70 00:00      
               another reason            01/01/70 00:00      
                  maybe You need Ethernet?            01/01/70 00:00      
                     Another issue...            01/01/70 00:00      
                  wrong? not really, but wasteful            01/01/70 00:00      
                  another reason 2            01/01/70 00:00      
                     there is no 'same time'            01/01/70 00:00      
                        OK there wasn't same but....            01/01/70 00:00      
                           Asynchronous?            01/01/70 00:00      
                           if I understand what you are saying            01/01/70 00:00      
                              Something like this            01/01/70 00:00      
                                 Modbus            01/01/70 00:00      
                                    swicth to modbus            01/01/70 00:00      
                                       Sample code            01/01/70 00:00      
                                    References            01/01/70 00:00      
                                 collisions            01/01/70 00:00      
   try 30 baud            01/01/70 00:00      
   Before jumping to pool named as "modbus"            01/01/70 00:00      
      You have a calculator!            01/01/70 00:00      
         what a waste of bandwith            01/01/70 00:00      
            Tradeoff            01/01/70 00:00      
               There is overhead you can save with no ill effect            01/01/70 00:00      
                  The point is...            01/01/70 00:00      
                     modbus exist does not make it pantyhose            01/01/70 00:00      
                        For a beginner...            01/01/70 00:00      
   Getting wet with modbus by drag from Russel            01/01/70 00:00      
   AT89S8252 and AT89S52            01/01/70 00:00      
      Nope!            01/01/70 00:00      
         AT89S5X with 24LC02            01/01/70 00:00      
            Lot of work??            01/01/70 00:00      
            Quoting previous posts            01/01/70 00:00      

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