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Group Pins

ArchiverArchiver Posts: 46,084
edited 2004-04-26 17:39 in General Discussion
I am new to programing in Pbasic. How do I group pins together as a
group. I need to read five pins together so that I can read them as
a whole number. I know there must be a way.

Thanks,

Troy

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2004-04-26 17:00
    There are special names for groups of pins. For example, INA is the first 4
    pins (P0-P3) and IND has the last 4 pins. In addition INH and INL are the
    two groups of 8 bits (P8-P15 and P0-P7, respectively).

    To do what you propose you'd probably want to knock off the top part of an 8
    bit group, so say:

    V=INL & $1F

    Something like that.

    Regards,

    Al Williams
    AWC
    *Kits!
    http://www.awce.com/kits.htm



    Original Message
    From: Troy Bakken [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=wV1hrHAIGkZipQNLWtShiBmoOE1erI6jtUwYo3Qpq_ukBF2ZhtRzhdPtSYiQ0B6t8g7N7pvsC_9fttHD]troybakken@y...[/url
    Sent: Monday, April 26, 2004 10:56 AM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Group Pins


    I am new to programing in Pbasic. How do I group pins together as a
    group. I need to read five pins together so that I can read them as
    a whole number. I know there must be a way.

    Thanks,

    Troy



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  • ArchiverArchiver Posts: 46,084
    edited 2004-04-26 17:39
    Pins are pre-grouped. You can read each individually (IN0 - IN15), in
    groups of four (nibbles = INA, INB, INC, IND), in groups of eight (bytes
    = INL, INH), or all 16 (INS) as a word.

    With your example, you'll need to read as a group of eight (INL or INH)
    and then mask out the unused pins. You may also need to shift the data,
    depending on your input alignments in the group.

    Let's say, for example, your inputs are P0 - P4. Easy.

    myInputs = INL & %00011111

    This reads the group INL (P0 - P7), then masks out the inputs on P5 -
    P7. But what if your inputs are not aligned on the LSB as above? What
    if your inputs are P2 - P6 and you want to read them as a number. Just
    tweak your mask value and add a shift operation:

    myInputs = INL & %01111100 >> 2

    Note that this only works with contiguous groups of pins. If your
    inputs are not contiguously grouped, you'll have to grunt it out. For
    example:

    myInputs.BIT0 = IN0
    myInputs.BIT1 = IN2
    myInputs.BIT2 = IN4
    myInputs.BIT3 = IN6
    myInputs.BIT4 = IN7

    Section 4 of the manual covers this stuff.


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

    Original Message
    From: Troy Bakken [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=MxOWPty49PNJll_PUNmAkyrJ-0YdH34MMn_09yHEeLh78sAwv0HFR1P3hN9npRA0JoXWenebrU_GAVMgMg]troybakken@y...[/url
    Sent: Monday, April 26, 2004 10:56 AM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Group Pins


    I am new to programing in Pbasic. How do I group pins together as a
    group. I need to read five pins together so that I can read them as
    a whole number. I know there must be a way.

    Thanks,

    Troy
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