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???
01/11/07 17:51
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 		 #130674 - Looks like a point of confusion
Responding to: ???'s previous message
Hi again Hazman,

If you want to use pull up resistors, then you have the LEDs correctly polarized. If you do not want to use pull up resistors, then you will need to turn the LEDs around.

In the case of no pull up resistors, you turn the LED off by writing a 1 to the port pin (which lets the port pin float), and you turn the LED on by writing a 0 to the port pin (which provides the ground for your LED circuit). You will also need to make certain that the other end is at Vcc.

As you have them drawn they will work if you provide pull up resistors. Of course, now you turn the LED on by writing a 1 to its port pin, and turn it off by writing a 0. However, and this is important, you will need a separate pull up resistor for each port pin. You seem to have drawn it with two (or more) port pins sharing a single pull up resistor. They can not share the same pull up resistor. That would just be shorting all of the port pins together.

Good luck,

Joe


List of 62 messages in thread
TopicAuthorDate
how can i use port 0 as output            01/01/70 00:00      
   read            01/01/70 00:00      
      not quite understand            01/01/70 00:00      
         READ            01/01/70 00:00      
            i'm blur            01/01/70 00:00      
               it is a \'1\', but not a \'high\'            01/01/70 00:00      
         Port 0 is open drain            01/01/70 00:00      
            connection between u-c with pull up?            01/01/70 00:00      
               Basics            01/01/70 00:00      
                  typo            01/01/70 00:00      
                     Doh!            01/01/70 00:00      
               The answer is...            01/01/70 00:00      
                  Sinking and Sourcing            01/01/70 00:00      
                     Correct!            01/01/70 00:00      
                  sending data using port 0?            01/01/70 00:00      
                     Yes            01/01/70 00:00      
                        LED display driver            01/01/70 00:00      
                           Port1 is better than port0 for this            01/01/70 00:00      
                              is it right like this?            01/01/70 00:00      
                                 NO            01/01/70 00:00      
                                 Where is the TB62726 in your circuit??            01/01/70 00:00      
                                    stiil stuck with port0            01/01/70 00:00      
                                       help me plz            01/01/70 00:00      
                                          drop the cute stuff            01/01/70 00:00      
                                    connections right or not?            01/01/70 00:00      
                                       Hallelujah!!            01/01/70 00:00      
                                          I already did            01/01/70 00:00      
                                          sorry            01/01/70 00:00      
                                       No            01/01/70 00:00      
                                 Looks like a point of confusion            01/01/70 00:00      
                                    It is not Right            01/01/70 00:00      
                                    Looks like total confusion!            01/01/70 00:00      
                                       looks like?            01/01/70 00:00      
                                    confused..            01/01/70 00:00      
                                       That is Right            01/01/70 00:00      
                                       the schematic is fine, BUT            01/01/70 00:00      
                                       You have damaged the micro!!            01/01/70 00:00      
                                    my assumption right now            01/01/70 00:00      
                                       basics            01/01/70 00:00      
                                          Deja Vu            01/01/70 00:00      
                                          Wyh not?            01/01/70 00:00      
                                             the difference is            01/01/70 00:00      
                                       See my recent post.            01/01/70 00:00      
                                          why not ?            01/01/70 00:00      
                                          No, you're wrong ...            01/01/70 00:00      
   Don't remove your earlier schematics!!            01/01/70 00:00      
      RightO            01/01/70 00:00      
         a good way to burn the port pin (and the LED)            01/01/70 00:00      
            Sorry Datasheet is different for what I am saying            01/01/70 00:00      
               NO, nada, niente, never, nie, non,, aldrig            01/01/70 00:00      
               Hair-raising...            01/01/70 00:00      
               Completely Incorrect!            01/01/70 00:00      
                  In practice..            01/01/70 00:00      
                     Please read specs properly            01/01/70 00:00      
                        What has survived your "tests" must be correct?            01/01/70 00:00      
      diagram attached            01/01/70 00:00      
         Connections are not correct!            01/01/70 00:00      
   Modifications            01/01/70 00:00      
      PWM without using 8051-Timer            01/01/70 00:00      
         New Topic; New Thread            01/01/70 00:00      
         Yes, but...            01/01/70 00:00      
         the usual question            01/01/70 00:00      

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