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dtmf question (straight pins vs crossed pins) — Parallax Forums

dtmf question (straight pins vs crossed pins)

cyberzernicscyberzernics Posts: 2
edited 2006-12-27 10:11 in BASIC Stamp
Can someone please explain me the difference between straight pins and crossed pins?

Also, please explain the relationship of the pins to these lookup values or code:

"D84#206B195A3*7C-" for straight pins
"D1234567890*#ABC-" for crossed pins

Comments

  • FranklinFranklin Posts: 4,747
    edited 2006-12-26 07:05
    Could you explain your question better? What device are you talking about?

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    - Stephen
  • cyberzernicscyberzernics Posts: 2
    edited 2006-12-26 20:08
    Sorry for not being clear. I am using the CM8880 DTMF Transceiver and I'm trying to understand the following sample code below. I just want to know when to use the lookup values "D84#206B195A3*7C-" and "D1234567890*#ABC-". The comments says 'straight pins' and 'crossed pins', but I don't know what is it talking about. I'm not even sure if it has something to do with CM8880.

    DTMFER:

    DTMF = INL & %00001111

    LOOKUP DTMF,[noparse][[/noparse]"D84#206B195A3*7C-"],DTMF 'STRAIGHT PINS

    'LOOKUP DTMF,[noparse][[/noparse]"D1234567890*#ABC-"],DTMF 'CROSSED PINS

    IF DTMF = "1" THEN DTMF1

    IF DTMF = "2" THEN DTMF2

    IF DTMF = "3" THEN DTMF3

    IF DTMF = "4" THEN DTMF4

    IF DTMF = "5" THEN DTMF5

    IF DTMF = "6" THEN DTMF6

    IF DTMF = "7" THEN DTMF7

    IF DTMF = "8" THEN DTMF8

    IF DTMF = "9" THEN DTMF9

    IF DTMF = "0" THEN DTMF0

    IF DTMF = "*" THEN OTHER

    IF DTMF = "#" THEN OTHER

    IF DTMF = "A" THEN OTHER

    IF DTMF = "B" THEN OTHER

    IF DTMF = "C" THEN OTHER

    IF DTMF = "D" THEN OTHER

    RETURN

    The rest of the code can be found here:

    http://www.repeater-builder.com/pix/rc2.bs2
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-12-27 03:29
    Hello,
    ·
    ·· Not sure about straight and crossed pins…Do you perhaps mean common bus key switches and matrix keys?

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    Chris Savage
    Parallax Tech Support
  • PARPAR Posts: 285
    edited 2006-12-27 07:11
    cyberzernics said...
    Can someone please explain me the difference between straight pins and crossed pins?

    Also, please explain the relationship of the pins to these lookup values or code:

    "D84#206B195A3*7C-" for straight pins
    "D1234567890*#ABC-" for crossed pins
    Have you tried to contact the program's author?

    ·················· [url=mailto:n0yox647@[remove-no-smam]iland.net]n0yox647@[noparse][[/noparse]remove-no-smam]iland.net[/url]

    PAR
  • Bruce BatesBruce Bates Posts: 3,045
    edited 2006-12-27 10:11
    cyberzernics -

    Based on the contents of the CM8870 data sheet, my guess would be that they're speaking about the ROW and COLUMN wires. If they are correctly wired (ROWS = ROWS, COLUMNS = COULUMNS) then you use one of the tables. If however, it's mis-wired (ROWS = COLUMNS, COLUMNS = ROWS) then you use the other table. With that in mind, the justaposition in the table is reasonably easy to see.

    What makes NO SENSE at all is the last "-" entry in both tables. That character is not present on a telco-style keypad, or in the DTMF sequence. Thus. for my money, that's an unnecessary entry, although it probably won't hurt anything. Moreover, I can't even see a way for it to be transmitted, as any bit pattern it might present would exceed 4 bits, and there are ONLY 4 data lines (D0-D3)!

    Regards,

    Bruce Bates

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