pic16f628a issue


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  1. #1

    Default pic16f628a issue

    So I am trying to write a hello world program of sorts for a 16f628a chip. I have a led hooked up to portb 3. Here is the code that is not working

    Code:
    Main:
    High PortB.3
    pause 100
    Low PortB.3
    pause 100
    goto Main
    The led is not turning on. Why is this not working?

  2. #2
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    Default Re: pic16f628a issue

    Do you have PortB set as output? You need TrisB.3 = 0 in your code.
    Regards
    CharlieM
    Using PBP3
    MCSPX

  3. #3


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    Default Re: pic16f628a issue

    Quote Originally Posted by c_moore View Post
    Do you have PortB set as output? You need TrisB.3 = 0 in your code.
    well I didnt, but even with that code at the top it does not work

  4. #4
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    Default Re: pic16f628a issue

    What config settings did you use?

    What PBP version do you have?

    PM or MPASM assembler?

    Robert

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    Default Re: pic16f628a issue

    How is your led connected, and what resistor value are you using for it ?

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    Default Re: pic16f628a issue

    Quote Originally Posted by Demon View Post
    What config settings did you use?

    What PBP version do you have?

    PM or MPASM assembler?

    Robert
    what is a config value?
    2.5 if I remember right
    mpasm

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    Default Re: pic16f628a issue

    Quote Originally Posted by aerostar View Post
    How is your led connected, and what resistor value are you using for it ?
    If i remember right it is connected to the positive end, then the negative end is grounded, and there is no resistor. But I know that the configuration is correct

  8. #8
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    Default Re: pic16f628a issue

    Technically, you're supposed to put a current-limitting resistor along with an average LED with 5 VDC; most use 330ohms. Does the LED still work on 5 VDC and a resistor? Confirming it isn't burnt is a good start.

    Basics on Configs here:
    http://www.picbasic.co.uk/forum/showthread.php?t=543

    Some overview on what files are used (I have v2.60, so it's about the same as 2.50 - the syntax for 16F is just a bit different):
    http://www.picbasic.co.uk/forum/showthread.php?t=15982

    Robert


    EDIT: Look at top right, try CONFIG 16F628A in Advanced Search.

    Here is one thread that came up:
    http://www.picbasic.co.uk/forum/showthread.php?t=9794
    Last edited by Demon; - 29th April 2012 at 05:26. Reason: Search feature and example

  9. #9


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    Default Re: pic16f628a issue

    Quote Originally Posted by Demon View Post
    Technically, you're supposed to put a current-limitting resistor along with an average LED with 5 VDC; most use 330ohms. Does the LED still work on 5 VDC and a resistor? Confirming it isn't burnt is a good start.

    Basics on Configs here:
    http://www.picbasic.co.uk/forum/showthread.php?t=543

    Some overview on what files are used (I have v2.60, so it's about the same as 2.50 - the syntax for 16F is just a bit different):
    http://www.picbasic.co.uk/forum/showthread.php?t=15982

    Robert


    EDIT: Look at top right, try CONFIG 16F628A in Advanced Search.

    Here is one thread that came up:
    http://www.picbasic.co.uk/forum/showthread.php?t=9794
    the led works, and I have been told by 2 friends of mine familiar with what I am doing that I dont need a resistor because of my setup.

    But even after reading that stuff I can still not get this working for the life of me. Here is my, still broken, code.
    Code:
    @ __config _INTRC_OSC_NOCLKOUT & _WDT_ON & _PWRTE_ON & _MCLRE_OFF & _BODEN_ON & _LVP_OFF
    
    Define OSC 4
    CMCON = 7 
    VRCON = 0 
    
    
    
    
    PortA=0
    TRISA=0000
    TRISB = 0000 
    PortB = 0000 
    
    
    Main:
    High PortB.3
    high PortA.1
    pause 1000
    Low PortB.3
    low PortA.1
    pause 1000
    goto Main


    Also, I just found these fuse settings in my programmer, should one of these settings be different?

  10. #10
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    Default Re: pic16f628a issue

    Did you comment out the config in the Include file as described here:
    http://www.picbasic.co.uk/forum/showthread.php?t=15982

    The config settings in your programmer should be ok. Compare them with what you put in your code.

    What happens exactly, do you get error messages?
    Compiles ok but no activity on circuit?

    Robert

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    Default Re: pic16f628a issue

    Quote Originally Posted by Demon View Post
    Did you comment out the config in the Include file as described here:
    http://www.picbasic.co.uk/forum/showthread.php?t=15982

    The config settings in your programmer should be ok. Compare them with what you put in your code.

    What happens exactly, do you get error messages?
    Compiles ok but no activity on circuit?

    Robert
    the config settings look the same.

    it compiles and programs perfectly, but nothing happens on the circuit.

  12. #12
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    Default Re: pic16f628a issue

    Look at Archangel's code here:
    http://www.picbasic.co.uk/forum/show...hlight=16f628a

    He has these also (for 16F628 - not sure if it applies to you):
    Code:
    T1CON = %00000011
    OPTION_REG = %01010111
    What if you disable BODEN and PWRTE?

    What about your voltage, it is at 5V right?

    I don't use the low voltage 16F628A, I used the regular 16F628.

    Robert

    P.S.: To get your code to come out right (missing %), hover your mouse over the A icon at far left when you post, you want to be in SOURCE mode, not WYSIWYG.


    EDIT: What about the resistor on MCLR?
    http://www.picbasic.co.uk/forum/showthread.php?t=16188
    His code works for 16F628A and internal oscillator.
    Note he is using PM instead of MPASM, so his CONFIG syntax is a bit different.
    He used CLKOUT instead of NOCLKOUT, not sure what difference that makes.

    Can you post a drawing of your circuit, a JPG from Paintbrush would be fine.
    Last edited by Demon; - 1st May 2012 at 02:26.

  13. #13


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    Default Re: pic16f628a issue

    Quote Originally Posted by Demon View Post
    Look at Archangel's code here:
    http://www.picbasic.co.uk/forum/show...hlight=16f628a

    He has these also (for 16F628 - not sure if it applies to you):
    Code:
    T1CON = %00000011
    OPTION_REG = %01010111
    What if you disable BODEN and PWRTE?

    What about your voltage, it is at 5V right?

    I don't use the low voltage 16F628A, I used the regular 16F628.

    Robert

    P.S.: To get your code to come out right (missing %), hover your mouse over the A icon at far left when you post, you want to be in SOURCE mode, not WYSIWYG.


    EDIT: What about the resistor on MCLR?
    http://www.picbasic.co.uk/forum/showthread.php?t=16188
    His code works for 16F628A and internal oscillator.
    Note he is using PM instead of MPASM, so his CONFIG syntax is a bit different.
    He used CLKOUT instead of NOCLKOUT, not sure what difference that makes.

    Can you post a drawing of your circuit, a JPG from Paintbrush would be fine.
    Got it working, I added some code from that thread and disabled boden and pwrte, I dont know what exactly did it but it works. And incase you were wondering, it is powered by a 3v source and I do not have a resistor anywhere/

    But if anyone in the future has this problem has this problem stumbles upon this thread, here is my code that works
    Code:
    @ __config _INTRC_OSC_NOCLKOUT & _WDT_ON & _PWRTE_OFF & _MCLRE_OFF & _BODEN_OFF & _LVP_OFF
    
    Define OSC 4
    
    
    LED4 VAR PortA.1
    CMCON = 7 
    VRCON = 0 
    PortA=0
    PortB = %00000000 
    T1CON = %00000011
    TRISA = 0 
    TRISB = %00000000 
    
    
    
    
    
    
    
    
    STARTMAIN:
    
    
    
    
    LED4=1
    
    
    PAUSE 250
    
    
    LED4=0
    
    
    Pause 250
    
    
    GOTO STARTMAIN
    
    
    END

  14. #14
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    Default Re: pic16f628a issue

    The Brown Out detect fuse solved our problem, now look at the datasheet and see why it works...
    Steve

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

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