can someone help me with RCTIME


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  1. #1
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    Hi and Welcome on the forum,
    Any specific reason why you want to use RcTime? What do you want to do?
    Steve

    It's not a bug, it's a random feature.
    There's no problem, only learning opportunities.

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    T.Jackson's Avatar
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    Smile

    Gotta be a Time Machine. Just has to be. This would be about the only use for RCTIME.

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    Could be, but why i'm asking is that many use RcTime to read a POT, while using the ADC is much efficient and don't need any extra capacitor.

    Let's see...
    Steve

    It's not a bug, it's a random feature.
    There's no problem, only learning opportunities.

  4. #4
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    Yeah - RCTIME is a bit inadequate for that, there's not enough span at the lower end. I think min is a few KΩ. Besides, relatively inefficient too, tying up a complex protocol for something so simple.

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    I could easily see throwing a few push buttons, each with their own resistor, on the same pin, with a parallel cap, and using RCTIME to figure out which switch was pressed.

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    Quote Originally Posted by skimask View Post
    I could easily see throwing a few push buttons, each with their own resistor, on the same pin, with a parallel cap, and using RCTIME to figure out which switch was pressed.
    That is a very good idea!

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    Quote Originally Posted by T.Jackson View Post
    Gotta be a Time Machine. Just has to be. This would be about the only use for RCTIME.
    Im starting with the basics but you discovered my evil plan! ^^

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    Wink my reasonings

    well, as a clarification I forgot to include. I am using the 16f88 as this projects chip. And I am trying to read a photoresistor or a pot. Mostly I am trying to carry over my knowledge of electronics from the basic stamp. And make sure I know how to do everything I had learned up till' now.

    If I can do that, I can still use the books I purchased for the basic stamp as a learning tool for the pic micro. As I have decided that the stamps are not cost effective, and want to learn at a little more depth.

    Also as a note, I have attempted to get it to work all digital, and on digital only ports with the same result.

    If there is a better way, do tell, however I still want to know how to get the command to work. ^^ thankyou.


    Quote Originally Posted by mister_e View Post
    Hi and Welcome on the forum,
    Any specific reason why you want to use RcTime? What do you want to do?
    Last edited by gandora; - 15th May 2007 at 18:04. Reason: extra info

  9. #9
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    As pointed out earlier, RCTIME is a digital function not analog. So you'll need to enable the port in digital mode. Your code gears the port up in analog mode. BS2 is an unpopular joke in my opinion.

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    Talking Its Alive!

    Quote Originally Posted by T.Jackson View Post
    As pointed out earlier, RCTIME is a digital function not analog. So you'll need to enable the port in digital mode. Your code gears the port up in analog mode. BS2 is an unpopular joke in my opinion.

    Alright Thankyou for your help i now got it to work. For other newbs who would prefer not make a fool of themselves. The working code is below.

    Thanks again. it now results in different things depending on the light. ^^

    Code:
    '---clock settings
            define OSC 8
            OSCCON = %1111110 ' sets internal osc to run at 8MHZ
    
    '----------turn analog on porta off, and use as digital input/output
            CMCON = 7 'Comparators off
            ANSEL = 0 'A/D off -- Port pins all digital
    '----------^^^^^^^^^^
    '----------the change is in this block of code
    
    '---** Constants
    
    rcpin var porta.3
    
    '---**variables
    
    rcreturn var byte
    
    '------**main program
    
    
    
    loop:  
    
    '----its rctime!
    pause 1000
    
    high rcpin
    pause 5 
    rctime rcpin,1,rcreturn
    low rcpin
    
    
    '----(end rctime) shows over folks ^^
    
    
    
    '----send serial feedback      
            serout2 porta.0, 16468, ["rc time was: ",dec rcreturn] 'call for data    
     '-----end serial feedback
    
    goto loop   'loop forever
    end

  11. #11
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    in case you're using a LDR (or high impedance analog source), i see some advantage of RCTime.. unless, i really don't. A simple transistor+few resistor + PIC adc, would be my solution if i need accuracy.

    Level detector? ---> PIC Comparator

    OR, PIC16F785 i've ordered a thousand of them yesterday, sOOOO much nice stuff on-board... built-in OP-AMP, 2 phase PWM + asynchronous feedback as a teaser...

    NEW TOY, NEW TOY
    Steve

    It's not a bug, it's a random feature.
    There's no problem, only learning opportunities.

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    Quote Originally Posted by T.Jackson View Post
    BS2 is an unpopular joke in my opinion.
    To me, ANY Basic Stamp are as good as PIC16F84

    But come-on... 40$ EACH
    Steve

    It's not a bug, it's a random feature.
    There's no problem, only learning opportunities.

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    Smile Furthur ponderences.

    So you said there was a way of reading a pot in analog? Is there any chance you could give me a little synopsis of how it is done? Thankyou.

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    Assuming your POT impedance is equal or less than the maximum recommended, you just need to feed the wiper to a PIC analog input and use the internal ADC.

    PBP ADCIN is a nice start point.
    Steve

    It's not a bug, it's a random feature.
    There's no problem, only learning opportunities.

  15. #15
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    This is for a 877 but it will help you get the picture.

    http://www.rentron.com/PICX2.htm

    Be sure to look at the speacial feature part of the data sheet for the PIC you are usinf as at this point the PIC are not "standard".

    There is a RCTIME and place for everything Upgrading from the BS2, you will enjoy the built in ADC on some PICs. If you have used an external ADC with the BS2, do not try and compare this with the ones built in. End result the same but how tou get there is another story.

    Have fun.
    Dave
    Always wear safety glasses while programming.

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    Quote Originally Posted by mister_e View Post
    To me, ANY Basic Stamp are as good as PIC16F84

    But come-on... 40$ EACH
    - you must be joking. BS2 hovers along at around 2,000 instructions p/sec. BS2 has two major short comings. 1) Overhead of the serial EEPROM which is the reason why it's so slow. 2) Cost - in Australia when BS2 was initially released it retailed for something like $100. I'd swap you a BS2 for a 16f84a any day. In fact, I'd even pay a bit of money on top. Honda Vs Ferrari basically.

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    Quote Originally Posted by T.Jackson View Post
    - you must be joking. BS2 hovers along at around 2,000 instructions p/sec. BS2 has two major short comings. 1) Overhead of the serial EEPROM which is the reason why it's so slow. 2) Cost - in Australia when BS2 was initially released it retailed for something like $100. I'd swap you a BS2 for a 16f84a any day. In fact, I'd even pay a bit of money on top. Honda Vs Ferrari basically.
    And who drives a Ferrari as there first car. The BS2 is a good way to get started. Compare to the cost of PBP or the time of learning assembly and cost of a good programmer...

    And about the swap. Your on. What is you mailing address. This would make the Scouting Troop I work with very happy. Do not worry about the "bit of money on top", paying for the shipping will be fine.
    Dave
    Always wear safety glasses while programming.

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    Yeah - I guess few people drive Ferraris as their first car, BS2 has its place. As far as the swap goes, I have never personally owned a BS2. I'd be more than happy to adopt some more 16f84's though. One of my old College teachers was mad into BS2. Come to think of it, he was a bit mad himself actually.
    Last edited by T.Jackson; - 16th May 2007 at 09:48.

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