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Newbie Alert !!!! — Parallax Forums

Newbie Alert !!!!

ArchiverArchiver Posts: 46,084
edited 2004-03-31 16:33 in General Discussion
I am trying to understand this but it makes no sense to me at all.So
if you got some crayons can you draw me a picture I can
understand.Here is the first part:
switch=INC & 7 ' only 3 switches
switch=switch ^ 7 ' reverse sense (active low->active high)

Here is the second part:
IF INC <> 15 THEN readloop

I guess my big question is what value do you apply to the pins
covered by INC.

Thanks,
Stan

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2004-03-31 15:18
    INC is the IO pin group that holds P8, P9, P10 and P11. What the code
    appears to be doing is reading that group, extracting three of the pins
    for the variable switch, then retesting the group and continuing at the
    label "readloop" if all inputs on INC are high.

    The inputs to the BASIC Stamp micro are digital: 0 (ground) and 1 (+5v).
    The code indicates active-low inputs. That means the inputs are
    pulled-up to Vdd (+5) through resistors (probably 10K) and a button
    connects between each of the pins and ground. When a button is open,
    the pin will see "1" (+5v), when the button is pressed the input will se
    "0" (ground).

    This is standard digital stuff. Since you've identified yourself as
    new, let me suggest you download our "What's A Microcontroller?" text
    from our web site.

    -- Jon Williams
    -- Applications Engineer, Parallax
    -- Dallas Office

    Original Message
    From: kingtweeter [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=x3vFJlc3l2qoesF1SSnrsAuTp5aUH-BsDpU9iImHojILea30Bmmv-QW7Chi0eJYkHCPI5IxNb9ij2rIsPAU]jamachine@c...[/url
    Sent: Wednesday, March 31, 2004 6:51 AM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Newbie Alert !!!!


    I am trying to understand this but it makes no sense to me at all.So
    if you got some crayons can you draw me a picture I can
    understand.Here is the first part:
    switch=INC & 7 ' only 3 switches
    switch=switch ^ 7 ' reverse sense (active low->active high)

    Here is the second part:
    IF INC <> 15 THEN readloop

    I guess my big question is what value do you apply to the pins
    covered by INC.

    Thanks,
    Stan







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  • ArchiverArchiver Posts: 46,084
    edited 2004-03-31 16:33
    Thanks for the reply Jon,
    And I will read that I am also going to post all of the code this
    time,because part of this still makes no sense[noparse]:([/noparse]IF INC <> 15 THEN
    readloop)the code length is 5 so you have 5 key presses if pin 8
    =1,pin9=2,pin10 =3,and if the code is 3,3,1,2,3 and it is looking
    for 15 that is my problem.

    Thans,
    Stan

    '{$STAMP BS2}
    ' Combo lock demo by Al Williams
    ' Shows how to use an RC network for generating
    ' a timeout
    rctrig CON 7 ' pin connected to capacitor
    codelen CON 5 ' length of combo
    lockrelay CON 0 ' turns on when unlocked
    timeout VAR IN7
    current VAR Byte
    switch VAR Byte
    test VAR Byte
    OUTPUT lockrelay
    LOW lockrelay ' locked!

    top:
    current=-1 ' before 1st digit
    ' The code jumps here to advance to the next test digit
    advance:
    current=current+1 ' look at next digit
    IF current=codelen THEN unlock ' or, if done, we got em all
    GOSUB resettimer ' reset timer on good key
    loop:
    GOSUB readsw ' read switches
    IF switch=0 THEN testtime ' no switches? Look for timeout
    LOOKUP current,[noparse][[/noparse]3,3,1,2,3],test ' get current key to compare for
    IF switch=test THEN advance ' right! Advance to next
    DEBUG "bad code",CR ' could make an obnoxious beep here
    GOTO top ' Start over from beginning
    testtime:
    IF timeout=0 THEN loop ' still time, so keep looking
    IF current=0 THEN top ' don't complain if no entry
    DEBUG "timeout",CR
    GOTO top
    unlock:
    DEBUG "unlocked",CR
    HIGH lockrelay
    GOTO top ' go again for debugging purposes
    'Read combo switches to switch variable
    ' You could customize this in many ways
    ' SWITCH will equal 0 (no key) or 1, 2, 3 for the 1, 2, or 3 keys
    readsw:
    switch=INC & 7 ' only 3 switches
    switch=switch ^ 7 ' reverse sense (active low->active high)
    IF switch=0 THEN noread ' nothing
    IF switch<4 THEN readsw_ret ' correct switch 3
    switch=3 ' top most switch
    readsw_ret:
    ' now switch=0, 1, 2, or 3
    PAUSE 25 ' debounce
    readloop:
    IF INC <> 15 THEN readloop ' wait for keys to go up
    PAUSE 25 ' debounce
    DEBUG ?switch
    noread:
    RETURN
    ' Reset RC timer
    resettimer:
    OUTPUT rctrig
    LOW rctrig ' discharge capacitor
    PAUSE 100 ' give it time
    INPUT rctrig
    RETURN
    Thanks

    Stan



    --- In basicstamps@yahoogroups.com, "Jon Williams" <jwilliams@p...>
    wrote:
    > INC is the IO pin group that holds P8, P9, P10 and P11. What the
    code
    > appears to be doing is reading that group, extracting three of the
    pins
    > for the variable switch, then retesting the group and continuing
    at the
    > label "readloop" if all inputs on INC are high.
    >
    > The inputs to the BASIC Stamp micro are digital: 0 (ground) and 1
    (+5v).
    > The code indicates active-low inputs. That means the inputs are
    > pulled-up to Vdd (+5) through resistors (probably 10K) and a button
    > connects between each of the pins and ground. When a button is
    open,
    > the pin will see "1" (+5v), when the button is pressed the input
    will se
    > "0" (ground).
    >
    > This is standard digital stuff. Since you've identified yourself
    as
    > new, let me suggest you download our "What's A Microcontroller?"
    text
    > from our web site.
    >
    > -- Jon Williams
    > -- Applications Engineer, Parallax
    > -- Dallas Office
    >
    >
    >
    Original Message
    > From: kingtweeter [noparse][[/noparse]mailto:jamachine@c...]
    > Sent: Wednesday, March 31, 2004 6:51 AM
    > To: basicstamps@yahoogroups.com
    > Subject: [noparse][[/noparse]basicstamps] Newbie Alert !!!!
    >
    >
    > I am trying to understand this but it makes no sense to me at
    all.So
    > if you got some crayons can you draw me a picture I can
    > understand.Here is the first part:
    > switch=INC & 7 ' only 3 switches
    > switch=switch ^ 7 ' reverse sense (active low->active
    high)
    >
    > Here is the second part:
    > IF INC <> 15 THEN readloop
    >
    > I guess my big question is what value do you apply to the pins
    > covered by INC.
    >
    > Thanks,
    > Stan
    >
    >
    >
    >
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the
    Subject
    > and Body of the message will be ignored.
    >
    > Yahoo! Groups Links
    >
    >
    >
    >
    >
    >
    >
    > This message has been scanned by WebShield. Please report SPAM to
    > abuse@p...
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