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???
01/02/08 19:31
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 		 #148936 - Serial port pins
Responding to: ???'s previous message
It might be a matter of taste but the circuit diagram needs some standardisation.

Unless the RS232 D9 connector is a special version for ISP it is misconnected. The RXD should go to pin 3 of the D connector. Also reserve space for wiring shorts to other pins.

If You plan to make the board from scratch make the layout very "roomy" so that it is easy to repair as needed.

Make the pullup/pulldown resistors an option either by a jumper field or by using sockets for resistor nets.

The +10V cap is missing from the MAX232. Note - this cap goes to VCC. Connecting it to GND will fry the MAX232.

There are also capacitor-less MAX232 circuits (MAX233) available.

Are You sure about the numbering of the LCD module? My DatenBlatt suggests a mirrored numbering.

Put a small PolySwitch or similar fuse to the power line - not to protect the board but to protect the power supply. That regulator is almost indestructible.

And finally most importantly. Enjoy while building it and do not give up. How do You think Erik got his experience - by purchasing readily built kits? No. Those have always the MAX232 +10V capacitor connected the proper way.


List of 56 messages in thread
TopicAuthorDate
8051 First time user schematic check            01/01/70 00:00      
   a perfunctionary check            01/01/70 00:00      
      And            01/01/70 00:00      
      suporvisor chip            01/01/70 00:00      
         re: Supervisor chip            01/01/70 00:00      
         go to maxim            01/01/70 00:00      
            Thanks/New Schematic            01/01/70 00:00      
               Supervisor Wrong            01/01/70 00:00      
                  You could have it wired up an running by now.            01/01/70 00:00      
                     and thus            01/01/70 00:00      
               the power LED has no series resistor            01/01/70 00:00      
               The MAX232 +10V Capacitor            01/01/70 00:00      
   Another hint            01/01/70 00:00      
      port 0 pins            01/01/70 00:00      
   startup project advise            01/01/70 00:00      
      Incrimental Stages....            01/01/70 00:00      
      thanks            01/01/70 00:00      
         a comment            01/01/70 00:00      
            Agree            01/01/70 00:00      
               why schematics???            01/01/70 00:00      
               lucky you            01/01/70 00:00      
   assembly            01/01/70 00:00      
      re SILabs devboards            01/01/70 00:00      
      yes, why not            01/01/70 00:00      
         suffer            01/01/70 00:00      
   check            01/01/70 00:00      
      even worse            01/01/70 00:00      
      Ground Symbol            01/01/70 00:00      
         beware of idiots            01/01/70 00:00      
            Great Example            01/01/70 00:00      
               PCB class            01/01/70 00:00      
               Agreed, but            01/01/70 00:00      
                  Advice for someone just starting            01/01/70 00:00      
            idiocracy            01/01/70 00:00      
         regarding ground vcc symbols            01/01/70 00:00      
   Serial port pins            01/01/70 00:00      
      reply to Esko            01/01/70 00:00      
         we are here to help            01/01/70 00:00      
      Thanks for the reply            01/01/70 00:00      
   you will have hard time...            01/01/70 00:00      
      serial port connections            01/01/70 00:00      
         serial port connections II            01/01/70 00:00      
            a vbery common mistake/confusion            01/01/70 00:00      
               ... plus the infinite variations...            01/01/70 00:00      
         Opinion            01/01/70 00:00      
            a comment on the comment            01/01/70 00:00      
               SPI            01/01/70 00:00      
   One more development card argument            01/01/70 00:00      
      sure, but do you get ICE functionality?            01/01/70 00:00      
         No ICE but wire wrap is OK            01/01/70 00:00      
            and so what            01/01/70 00:00      
               To learn ?            01/01/70 00:00      
                  learning - modifying SMT            01/01/70 00:00      
                     Bino microscope            01/01/70 00:00      
                        not to worry            01/01/70 00:00      
                        site showing how to solder/desolder SMT'S            01/01/70 00:00      

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