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???
07/01/06 15:09
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 		 #119513 - Answers
Responding to: ???'s previous message
Ali said:
I didnot understand what u say about bouncing,my eng.is also poor and knowledge too.

Try this:

http://www.8052.com/forum/read.phtml?id=119512


Ali said:
and now how can i made keypad.is keypad is simple arrangement of rows or columns or i need some resistances to make a keypad/

Have a look at this thread:

http://www.8052.com/forum/read.phtml?id=88596


Ali said:
LEDs turn ON at port 3, according to input . e.g input 255... 7 LEDs On.
tell me what is pullup resistance.

You mean current limit resistance? No less than 1k8 when directly driving (sinking!) the LED currents.
You could use a 74HCMOS buffer connected to Port3 to drive the LEDs with some higher currents.

Kai


List of 36 messages in thread
TopicAuthorDate
4x3 keypad interfacing with At89c51            01/01/70 00:00      
   5 errors            01/01/70 00:00      
      Nice attitude!            01/01/70 00:00      
         If the approach is that anyone can get h            01/01/70 00:00      
            Do we know him?            01/01/70 00:00      
               Switch Depressed?            01/01/70 00:00      
                  continous and continous            01/01/70 00:00      
                     Thanks Erik!            01/01/70 00:00      
                  Taking samples            01/01/70 00:00      
                     debounce scheme.            01/01/70 00:00      
                        How to debounce without jumps and branch            01/01/70 00:00      
                           Thank you Kai...            01/01/70 00:00      
                           Having gone through your detailed descri            01/01/70 00:00      
                              Yes, I think so            01/01/70 00:00      
                                 Could you assist me to know that            01/01/70 00:00      
                                    Vertically incrementing            01/01/70 00:00      
                                       Thanks            01/01/70 00:00      
               Homework it is            01/01/70 00:00      
                  "Guilty"...            01/01/70 00:00      
   Post your code            01/01/70 00:00      
      2            01/01/70 00:00      
         There have been several threads            01/01/70 00:00      
         How to post code            01/01/70 00:00      
         why so complex            01/01/70 00:00      
         What Compiler ?            01/01/70 00:00      
            Compiler.KEIL            01/01/70 00:00      
         general idea            01/01/70 00:00      
            Diodes to prevent ghosting            01/01/70 00:00      
    Algorithm for Scanning 4*4 Keypad            01/01/70 00:00      
      thanks            01/01/70 00:00      
         If you'd searched, you'd have had this            01/01/70 00:00      
            Search term "4x4 keypad"            01/01/70 00:00      
   check this code.            01/01/70 00:00      
      Answers            01/01/70 00:00      
   Sorry kai.            01/01/70 00:00      
      keypad scanner in C            01/01/70 00:00      

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