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???
04/23/05 13:06
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#92231 - It is possible to do but why.....
Responding to: ???'s previous message
The analogue scheme to encode multiple switches into a single wire is possible...but in my book a waste of time. I can say that I have seen it done in products but I have heard about many problems of reliability for those same products. The required circuitry alone makes it hard to get working and the result is still a pain in the behind to get a stable result.

For local switches which are near to the microcontroller a much better result can be had with using a matrix connected to port pins. If there is a shortage of I/O pins then get more....easy solution these days. The best additional I/O can be attained through use of a small microcontroller running as a slave device. Interface via some serial technique using UART, I2C, SPI etc.

If the switches are remote then the serial technique lends itself directly !!

If isolation is really required it is easier to isolate a single serial line than a whole bank of switches.

Michael Karas


List of 14 messages in thread
TopicAuthorDate
ADC as digital input            01/01/70 00:00      
   Saturation            01/01/70 00:00      
      good point            01/01/70 00:00      
      URL            01/01/70 00:00      
         all good, but            01/01/70 00:00      
         optocouplers            01/01/70 00:00      
            Re: ADC as digital input            01/01/70 00:00      
               go analog            01/01/70 00:00      
                  schematic            01/01/70 00:00      
                     It is possible to do but why.....            01/01/70 00:00      
                     opto            01/01/70 00:00      
   Possible but troublesome...            01/01/70 00:00      
      very informative            01/01/70 00:00      
      overcomming opto difference            01/01/70 00:00      

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