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Michael Karas
01/20/12 08:17
Read: 472 times
Beaverton Or
USA


 
#185590 - ? Not Muxing ?
Responding to: Erik Malund's previous message
From the schematic description it does not sound like the OP is using display multiplexing at all. He is simply driving a series of 7-segment registers off a series connected set of shift registers.

In his application he really only needs to shift the data from the internal memory storage locations out to the shift registers + displays when there has been a change to the display content. It can be simpler code design and implementation to simply setup a timer interrupt that periodically refreshes the display from the internal memory variables and shifts that data out to the shift registers. That way the mainline program code can simply manage the memory variables and input switch detection and let the timer interrupt take care of keeping the display up to date.

In this proposed case of using the timer interrupt to update the display there would be no need to run those updates any faster than necessary to keep up with changes to the display caused by the mainline code. One could certainly choose to use a greater than 120 Hz update but it would be unnecessary. A 12 Hz update would work just as well.

Michael Karas




List of 44 messages in thread
TopicAuthorDate
switch interfacing      Anil Kumar      01/11/12 00:38      
   What?      Per Westermark      01/11/12 00:58      
      switch interfacing      Anil Kumar      01/11/12 01:39      
         The 7-segment digits will not handle switches      Per Westermark      01/11/12 02:57      
   Perhaps this may be useful to you      Maunik Choksi      01/11/12 03:53      
      4 buttons - not full keypad      Per Westermark      01/11/12 04:39      
         switch interfacing      Anil Kumar      01/12/12 00:06      
            That is called edit mode      Maunik Choksi      01/12/12 01:55      
               switch interfacing      Anil Kumar      01/12/12 22:50      
                  You need to study some examples      Maunik Choksi      01/12/12 23:51      
                     switch interfacing      Anil Kumar      01/13/12 00:10      
                  Details details - and where is debounce/repeat handling?      Per Westermark      01/13/12 01:20      
                     switch interfacing      Anil Kumar      01/14/12 00:59      
            Why should this be a problem??      Kai Klaas      01/12/12 07:53      
            interfacing your switches has nothing to do with LED's      Richard Erlacher      01/12/12 22:02      
   MUX LED AS O/P PIN      Satish S Munot      01/14/12 19:47      
      Switch interfacing      Anil Kumar      01/19/12 23:19      
         divide and conquer      Mahmood Elnasser      01/20/12 01:35      
         simplified step-by-step way to post your schematic        KONSTANTINOS L. ANGELIS      01/20/12 02:12      
            remember      Erik Malund      01/20/12 07:31      
               ? Not Muxing ?      Michael Karas      01/20/12 08:17      
   switch interfacing      Anil Kumar      01/21/12 01:57      
      You need lots of resistors      David Prentice      01/21/12 04:34      
         (Back to) Basics      Andy Neil      01/21/12 05:17      
            multiplex 5 digits      David Prentice      01/21/12 05:43      
               Don't think anyone would want 1:35 degenerate "multiplexing"      Per Westermark      01/21/12 05:52      
                  Have I done the sums wrong?      David Prentice      01/21/12 06:06      
                     No but multiplexing requires few driver lines      Per Westermark      01/21/12 06:17      
                        You MUST have digit drvers      David Prentice      01/21/12 07:00      
                           You missed '4094 OE+PWM for luminocity      KONSTANTINOS L. ANGELIS      01/21/12 09:47      
               No multiplexing needed...      Kai Klaas      01/21/12 07:33      
                  switch interfacing      Anil Kumar      01/21/12 07:46      
                     What help?      Andy Neil      01/21/12 08:33      
                     how?      Erik Malund      01/21/12 08:34      
                     Ah, a homework, right?      Kai Klaas      01/21/12 09:21      
                        switch interfacing      Anil Kumar      01/21/12 09:55      
                           language?      Erik Malund      01/21/12 10:37      
                           i have no logical idea how i write code      Andy Neil      01/21/12 10:40      
                           You need...      Kai Klaas      01/22/12 07:07      
                              Making a seven segment display blink      Andy Neil      01/22/12 07:19      
                                 The 4094 chip has an OE pin      David Prentice      01/22/12 07:48      
                              switch interfacing      Anil Kumar      01/22/12 10:57      
   switch interfacing      Anil Kumar      01/31/12 22:07      
      would you provide some feedback ?      KONSTANTINOS L. ANGELIS      02/01/12 03:35      

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