Random number -> Corresponding LED lit (n00besque content contained)


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  1. #1
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    LED1 = !(MyByte != 1)
    LED2 = !(MyByte != 2)
    LED3 = !(MyByte != 3)
    LED4 = !(MyByte != 4)
    LED5 = !(MyByte != 5)
    LED6 = !(MyByte != 6)
    DT

  2. #2
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    Default Re: Random number -> Corresponding LED lit (n00besque content contained)

    Quote Originally Posted by Darrel Taylor View Post
    LED1 = !(MyByte != 1)
    LED2 = !(MyByte != 2)
    LED3 = !(MyByte != 3)
    LED4 = !(MyByte != 4)
    LED5 = !(MyByte != 5)
    LED6 = !(MyByte != 6)
    Excellent, the top of my fishing rod is moving a touch!

    but I don't understand the response!

    eg if the random number comes out as 1, meaning I want to light LED1.....normally - if wanting to light LED1 for 200ms, I'd simply do this....
    Code:
    HIGH LED1
    PAUSE 200
    LOW LED1
    PAUSE 200
    but, how do I do this......

    Code:
    HIGH LED'result_of_random_number'
    PAUSE 200
    LOW LED'result_of_random_number'
    PAUSE 200
    Apologies if that is what you just told me Darrel, but I'm not sure how to use the info you gave me (that'll be the n00bishness that's never far away from all I do!)

  3. #3
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    Change the conditions on me eh ...

    How about ...
    Code:
    ;---------------------------------------
    Main:
        Random MyWord
        MyByte=(MyWord//6)+1
        GOSUB HIGH_LED
        PAUSE 200
        GOSUB LOW_LED
        PAUSE 200
    GOTO Main
    ;---------------------------------------
     
    HIGH_LED:
      SELECT CASE MyByte
        CASE 1 : HIGH LED1
        CASE 2 : HIGH LED2
        CASE 3 : HIGH LED3
        CASE 4 : HIGH LED4
        CASE 5 : HIGH LED5
        CASE 6 : HIGH LED6
      END SELECT
    RETURN
     
    ;---------------------------------------
    LOW_LED:
      SELECT CASE MyByte
        CASE 1 : LOW LED1
        CASE 2 : LOW LED2
        CASE 3 : LOW LED3
        CASE 4 : LOW LED4
        CASE 5 : LOW LED5
        CASE 6 : LOW LED6
      END SELECT
    RETURN
    DT

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    Default Re: Random number -> Corresponding LED lit (n00besque content contained)

    Hey Darrel...that works a treat ...I've now got pretty twinkly Blue leds randomly flashing before my eyes (which strangely, makes me feel warm inside).

    I note that a fair few of the random numbers are the same as the previous (I guess when you've only six to choose from, then that's bound to happen!), so I'll sit down for a few weeks & try & code this out!

    Many thanks!

    Hank.

    Edit: Actually, dialing out the successive repeats only took a couple of minutes...

    Code:
    MyWord var Word
    MyByte var Byte
    previous_random var Byte
    ;---------------------------------------
    Main:
        Random MyWord
        MyByte=(MyWord//6)+1
        if previous_random = MyByte then goto Main
        GOSUB HIGH_LED
        PAUSE 50
        GOSUB LOW_LED
        PAUSE 50
        previous_random = MyByte
    GOTO Main
    ;---------------------------------------
     
    HIGH_LED:
      SELECT CASE MyByte
        CASE 1 : HIGH LED1
        CASE 2 : HIGH LED2
        CASE 3 : HIGH LED3
        CASE 4 : HIGH LED4
        CASE 5 : HIGH LED5
        CASE 6 : HIGH LED6
      END SELECT
    RETURN
     
    ;---------------------------------------
    LOW_LED:
      SELECT CASE MyByte
        CASE 1 : LOW LED1
        CASE 2 : LOW LED2
        CASE 3 : LOW LED3
        CASE 4 : LOW LED4
        CASE 5 : LOW LED5
        CASE 6 : LOW LED6
      END SELECT
    Last edited by HankMcSpank; - 22nd April 2011 at 22:48.

  5. #5
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    Default Re: Random number -> Corresponding LED lit (n00besque content contained)

    Just had a sleep on this - I've never previously used case, and now I fresh look at it, to my eyes it's just a load of IFs?

    For example....

    Code:
    HIGH_LED:
      SELECT CASE MyByte
        CASE 1 : HIGH LED1
        CASE 2 : HIGH LED2
        CASE 3 : HIGH LED3
        CASE 4 : HIGH LED4
        CASE 5 : HIGH LED5
        CASE 6 : HIGH LED6
      END SELECT
    RETURN
    could be written as...

    Code:
    IF MYBYTE = 1 THEN HIGH LED1
    IF MYBYTE = 2 THEN HIGH LED2
    IF MYBYTE = 3 THEN HIGH LED3
    IF MYBYTE = 4 THEN HIGH LED4
    IF MYBYTE = 5 THEN HIGH LED5
    IF MYBYTE = 6 THEN HIGH LED6
    So when to use case & when to use if?

    Going back 20 years to when I used to write simple VMS DCL programs, I could construct code like thus...

    HIGH "LED"+'MyByte'

    the stuff inbetween " " was text & stuff in the ' ' was the value held in a variable

    therefore the above would actually run as.....

    HIGH LED1 (assuming MyByte held 1) ......presumably no similar ways of constucting in Picbasic?

  6. #6
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    Default Re: Random number -> Corresponding LED lit (n00besque content contained)

    Select Case is a lot like a "Load of IF's" with a few differences.
    1. It removes some of the (n00besque content contained) look and feel.
    2. Only the first "CASE" that evaluates TRUE will execute, then it exits the SELECT block.
      In your list of IF's, if the first one is true, it still goes on and evaluates all the other IF's too.
      This allows more complex logic, where more than one test can be true, but only the first one is acted on.
    The same functionality using IF statements would look like this ...
    Code:
    IF MYBYTE = 1 THEN
        HIGH LED1
    ELSE
        IF MYBYTE = 2 THEN
            HIGH LED2
        ELSE
            IF MYBYTE = 3 THEN
                HIGH LED3
            ELSE
                IF MYBYTE = 4 THEN
                    HIGH LED4
                ELSE
                    IF MYBYTE = 5 THEN
                        HIGH LED5
                    ELSE
                        IF MYBYTE = 6 THEN
                            HIGH LED6
                        ENDIF
                    ENDIF
                ENDIF
            ENDIF
        ENDIF
    ENDIF
    OR, if you have PBP 2.60 you could do it like this ...
    Code:
    IF MYBYTE = 1 THEN 
        HIGH LED1
    ELSEIF MYBYTE = 2 THEN 
        HIGH LED2
    ELSEIF MYBYTE = 3 THEN 
        HIGH LED3
    ELSEIF MYBYTE = 4 THEN 
        HIGH LED4
    ELSEIF MYBYTE = 5 THEN 
        HIGH LED5
    ELSEIF MYBYTE = 6 THEN 
        HIGH LED6
    ENDIF
    It may not seem like much difference with this simple example, but with large SELECT CASE blocks using more complex comparisons, it can save a boat load of execution time not having to evaluate every condition.

    * SELECT CASE is also much easier to read. Especially when it's not your program.

    PicBasic Pro, was written to generate the Smallest and Fastest code possible. As it is the HIGH/LOW statements only use a couple of instruction cycles. If you add in the abilities to use them like array's and access pins non-contiguously, it would make EVERY HIGH/LOW statement Bigger and Slower, breaking everyone's code, and causing more complaints than not having those abilities produces.
    Last edited by Darrel Taylor; - 23rd April 2011 at 16:29.
    DT

  7. #7
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    Default Re: Random number -> Corresponding LED lit (n00besque content contained)

    Many thanks Darrel....crystal clear now

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