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???
01/21/12 14:00
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 		 #185602 - You MUST have digit drvers
Responding to: ???'s previous message
To keep within the chip PORT ratings, the average multiplexed current per segment is fairly small (0.74mA).

With an 8051, you would have a port sink the current from the segments. The common-anode will be controlled via a PNP or driver chip. The peak digit current is high. e.g. 26mA sourced by the PNP. Traditional 8051 cannot source current anyway.

Yes. the display will be visible. Just not very bright. With a segment driver chip AND a digit driver chip, you can have a good display.

All the same, Anil's solution is very practical.

David.


List of 44 messages in thread
TopicAuthorDate
switch interfacing            01/01/70 00:00      
   What?            01/01/70 00:00      
      switch interfacing            01/01/70 00:00      
         The 7-segment digits will not handle switches            01/01/70 00:00      
   Perhaps this may be useful to you            01/01/70 00:00      
      4 buttons - not full keypad            01/01/70 00:00      
         switch interfacing            01/01/70 00:00      
            That is called edit mode            01/01/70 00:00      
               switch interfacing            01/01/70 00:00      
                  You need to study some examples            01/01/70 00:00      
                     switch interfacing            01/01/70 00:00      
                  Details details - and where is debounce/repeat handling?            01/01/70 00:00      
                     switch interfacing            01/01/70 00:00      
            Why should this be a problem??            01/01/70 00:00      
            interfacing your switches has nothing to do with LED's            01/01/70 00:00      
   MUX LED AS O/P PIN            01/01/70 00:00      
      Switch interfacing            01/01/70 00:00      
         divide and conquer            01/01/70 00:00      
         simplified step-by-step way to post your schematic            01/01/70 00:00      
            remember            01/01/70 00:00      
               ? Not Muxing ?            01/01/70 00:00      
   switch interfacing            01/01/70 00:00      
      You need lots of resistors            01/01/70 00:00      
         (Back to) Basics            01/01/70 00:00      
            multiplex 5 digits            01/01/70 00:00      
               Don't think anyone would want 1:35 degenerate "multiplexing"            01/01/70 00:00      
                  Have I done the sums wrong?            01/01/70 00:00      
                     No but multiplexing requires few driver lines            01/01/70 00:00      
                        You MUST have digit drvers            01/01/70 00:00      
                           You missed '4094 OE+PWM for luminocity            01/01/70 00:00      
               No multiplexing needed...            01/01/70 00:00      
                  switch interfacing            01/01/70 00:00      
                     What help?            01/01/70 00:00      
                     how?            01/01/70 00:00      
                     Ah, a homework, right?            01/01/70 00:00      
                        switch interfacing            01/01/70 00:00      
                           language?            01/01/70 00:00      
                           i have no logical idea how i write code            01/01/70 00:00      
                           You need...            01/01/70 00:00      
                              Making a seven segment display blink            01/01/70 00:00      
                                 The 4094 chip has an OE pin            01/01/70 00:00      
                              switch interfacing            01/01/70 00:00      
   switch interfacing            01/01/70 00:00      
      would you provide some feedback ?            01/01/70 00:00      

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