TTL input - 3rd states possible?


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  1. #1
    Join Date
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    Hi,

    See tip #3:

    http://ww1.microchip.com/downloads/e...doc/40040b.pdf

    Best regards,

    Luciano

  2. #2
    Join Date
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    Default Good documentation

    Thanks to both of you,

    The Tips & Tricks documentation is cool :-)

    I'll have a try with tis stuff.
    Roger

  3. #3
    Join Date
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    Unhappy Can't get it working...

    Well,

    After a few hours trying to get a positiv result, I just got nothing working.

    I would like to read two buttons connected to one pin.

    The states are "0" and "1". The third "Z" state is not relevant to me here.

    To make sure I have an intermediate level, I use a 2 resistor divider like described in the first post.

    Currently, I can't get clear "0" or "1" states.

    Any idea?

    Code:
    OSCCON       = %01100000  '4MHz
    OPTION_REG   = %10000000  'D I S A B L E PORTB's Pull-Ups for buttons
    ANSEL        = %00000000  'Disable Analogue Inputs
    TRISB        = %00010000  'Inputs/Outputs
    PORTB        = %00000000  'Drive all ports low
    
    MAIN:
        IF PORTB.5 = 0 THEN PORTB.0 = 1
        IF PORTB.5 = 1 THEN PORTB.1 = 1
        PAUSE 1000
        PORTB.0 = 0
        PORTB.0 = 0
        Goto MAIN
        end
    I use PORTB.5 of my PIC16F88 for buttons because it is a TTL input only.
    Roger

  4. #4
    Join Date
    Feb 2003
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    Smile

    Code:
    TRISB        = %00010000  'Inputs/Outputs
    you have PORTB.4 set as input, not PORTB.5
    Paul Borgmeier
    Salt Lake City, UT
    USA
    __________________

  5. #5
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    Red face How can I be so blind?

    Thanks Paul,

    It was again far to obvious to me (the tree in the forest story...).

    I'll try again tomorrow and let you know.

    Thanks a lot.
    Roger

  6. #6
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    Default Just tried - didn't want to go to bed frustrated...

    Well,

    I've still got one led always ON.

    In my understanding, I should get a state where no Led is ON.

    Is this correct?
    Roger

  7. #7
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    Quote Originally Posted by flotulopex View Post
    Well,

    I've still got one led always ON.

    In my understanding, I should get a state where no Led is ON.

    Is this correct?
    Show us your code again...

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