Need Help! Reversed Logic voltage to PICSTEP- What component to be replaced?


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Thread: Reversed Logic voltage to PICSTEP- What component to be replaced?

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    Member Khalid's Avatar
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    Default Reversed Logic voltage to PICSTEP- What component to be replaced?

    I have developed the Picstep version 4 board but i did not install the IDC cable as my BOB only requires STEP and DIR signals. Today i accidentally reversed the Logic voltage cables so that instead of installation of +5V DC wire to the +5V Logic i install the +5V to the Gnd... The result was my PIC become too hot as soon i realize what i did wrong i removed the cables...

    Fortunately most of the capacitors are ceramic or MKT type (non polar) so i am not worried about them But:
    1- I am sure that the PIC is blown away.
    2- What components else might be blown away?... XTAL and LMD?????

    Anyone can tell me should i replace all the components and discard them? Or should i replace the 20MHz XTAL?

    Similar Threads:
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    Community Moderator Al_The_Man's Avatar
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    I doubt if the XTAL was damaged as it usually is connected to two pins on the PIC and isolated from DC -ve by two caps, if this is the configuration you have?
    Probably just the PIC suffered, if you have any electrolytic's or Tantalum on board, you could remove them and test if need be.
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
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    Member Khalid's Avatar
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    Thanks Al, I do have the electrolytic on the board.. I hae replaced the PIC as well as the Xtal.. Two wires (+5V and GND) from the ATX computer power supply, i am using to give the Logic voltage to the PICstep... I have connected 24VDC and GND on the PICstep board for Motor powering.. My Motor has total 6 wires so i have just left the both COMMON wires unconnected..the rest of the 4 wires are connected to the board A A' and B B'...

    Following is my observation... With the motor connected and the both the Power supply enabled and the PIC install..My motor do not hold...

    But when i keep finger under the PIC and Xtal soldering joints, Motor holds and i can't rotate it by fingers... But as i removed the fingers from the Xtal/Pic soldering joints the motor do not hold..
    I thought that the cold solder may be their but the Digital Meter shows continiuty of all the joints...

    1-Whats going wrong?
    2- Should i make ENABLE pin to ground?
    3-If the Motors hold it means that LMD and other Electrolytic capacitors are working well...

    NOTE:
    I am using 20MHz Xtals with 22PF capacitors.

    http://free3dscans.blogspot.com/ http://my-woodcarving.blogspot.com/
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    Community Moderator Al_The_Man's Avatar
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    I had a weird problem like that once and the reason turned out to be the fact I had not had the right config string in the asm code and the power up reset was not set for internal pull up.
    Every time if I touched the board it would set it.
    Is this a pre-programmed Pic or are you programming it? What PIC IC is it?.
    If there is nothing connected to the Master Clear pin, you could take it high to see if it runs.
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


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    Community Moderator Al_The_Man's Avatar
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    I found a schematic of the board, and MCLR pin 1 goes to +5 so it may not be the cause if this is connected.
    What about the stop input?
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


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    Member robe_uk's Avatar
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    Hi
    you have to ground the enable line and also feed a step pulse for the motors to hold. So tie your enable to ground, with standard code the motors will not hold till it see's a pulse on the step pin.


    Cheers Rob

    I'll get it finished sometime after I start it.....


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    Member robe_uk's Avatar
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    did you get your pic's programmed ok?

    I'll get it finished sometime after I start it.....


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    Member Khalid's Avatar
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    @Al:
    I have QL-2006 advance PIC programmer and i am programming the PIC Myself. Hex code uploaded to the PIC successfully without Error with all Configuration Bits. Attached is also the screen shot of software after reading Back the Hex code from the PIC. The Right side of the initial and re-read Hex file has different characters and i think this is due to the placing of configuration bits.

    What do you mean by STOP input.Please clarify.

    @robe_uk:
    A) I have ground the Enable Pin 01 to the GROUND with a Jumper but nothing happen. The motor do not hold.
    B) As the Modular Card PICSTEP is not connected to the BOB, so can i externally give inputs to the STEP PIN?
    Should i provide +5V DC to step pin to check or connect it to GND. Your help and opinion needed.

    C) The PIC is programmed successfully as per attached picture and above points.

    Attached Thumbnails Attached Thumbnails Reversed Logic voltage to PICSTEP- What component to be replaced?-hex-file-selected-jpg   Reversed Logic voltage to PICSTEP- What component to be replaced?-hex-code-jpg   Reversed Logic voltage to PICSTEP- What component to be replaced?-bit-configuration-settings-jpg   Reversed Logic voltage to PICSTEP- What component to be replaced?-uploaded-code-read-pic-jpg  

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    Member Khalid's Avatar
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    If someone have a working HEX file can share with me please.

    http://free3dscans.blogspot.com/ http://my-woodcarving.blogspot.com/
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    Member Khalid's Avatar
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    Hmmm... In above picture i have mistakenly selected PIC 16LF628A but whether this may be the cause of trouble?

    http://free3dscans.blogspot.com/ http://my-woodcarving.blogspot.com/
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    Gold Member doorknob's Avatar
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    Quote Originally Posted by Khalid View Post
    Following is my observation... With the motor connected and the both the Power supply enabled and the PIC install..My motor do not hold...

    But when i keep finger under the PIC and Xtal soldering joints, Motor holds and i can't rotate it by fingers... But as i removed the fingers from the Xtal/Pic soldering joints the motor do not hold..
    I thought that the cold solder may be their but the Digital Meter shows continiuty of all the joints...
    I have no experience with that circuit, but I am wondering whether the symptom you have described could be caused by a balky oscillator, with a crystal that does not want to start oscillating.

    Is there any indication on the board (such as a blinking LED that is under the direct control of the PIC firmware) that the PIC is actually getting a clock signal when you don't have your finger under the crystal circuitry? If the oscillator does not start reliably then you will have problems. It might be possible that the capacitance values that you are using are not well matched to the crystal.



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    Community Moderator Al_The_Man's Avatar
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    Is this the schematic you are working with?
    http://www.jrkerr.com/pstep_bd.pdf
    There is an active high E-stop input, which would indicate that this has to be taken low to remove the stop.
    My programmer won't allow a different PIC than designated to be programmed?
    What is the PIC you are using?
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


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    Quote Originally Posted by doorknob View Post

    Is there any indication on the board (such as a blinking LED that is under the direct control of the PIC firmware) that the PIC is actually getting a clock signal when you don't have your finger under the crystal circuitry?
    Ans: Unfortunately no such LED indication on the PICSTEP.
    Quote Originally Posted by doorknob View Post
    If the oscillator does not start reliably then you will have problems. It might be possible that the capacitance values that you are using are not well matched to the crystal.
    I have used 33pf and currently using 22PF capacitors(ceramic) across the Xtal(20MHz)..The problem still persist.

    http://free3dscans.blogspot.com/ http://my-woodcarving.blogspot.com/
    http://my-diysolarwind.blogspot.com/


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    Quote Originally Posted by Al_The_Man View Post
    Is this the schematic you are working with?
    http://www.jrkerr.com/pstep_bd.pdf
    There is an active high E-stop input, which would indicate that this has to be taken low to remove the stop.
    My programmer won't allow a different PIC than designated to be programmed?
    What is the PIC you are using?
    Al.
    Hi Al,
    I am working on Alan designed circuit of PICSTEP..You can find the hardware and Firmware here:
    www.fromorbit.com | Where ideas can hurt!
    you can download files from here:
    https://github.com/alangarf/picstep
    Attached is the Schematic.
    I am using PIC 16F628A

    Attached Thumbnails Attached Thumbnails Reversed Logic voltage to PICSTEP- What component to be replaced?-picstep_v4_0_schema-pdf  
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    Member robe_uk's Avatar
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    Hi
    I have not used the programmer you have but I would say yes select the correct PIC, fuses are set in the hex so you should not have to change anything there. You can download the firmware source code and compile it yourself, you can see it the code the different options the can be selected by commenting and uncommenting code.

    With the enable grounded you can put a pulse onto the step pin, when i originally built mine I just toggled the step input from +5v to 0v to +5v to 0v etc and the motor should step, although with microstepping you have to toggle a lot to see the motor move, if things are working correctly on the picstep once you toggle the input on the step pin the motors will hold provided the enable is 0v

    I'll get it finished sometime after I start it.....


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    Gold Member doorknob's Avatar
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    Quote Originally Posted by Khalid View Post
    Ans: Unfortunately no such LED indication on the PICSTEP.


    I have used 33pf and currently using 22PF capacitors(ceramic) across the Xtal(20MHz)..The problem still persist.
    Can you tell from the firmware source code whether there is any output pin from the PIC that you can probe to determine whether or not it is actively running the firmware?

    It has been about five years or so since I last worked with PICs, so I don't remember all of the standard signals offhand, but if you can not demonstrate that your oscillator is starting and running reliably then nothing else that you do will be running reliably. Therefore, my guess is that any changes that you may make to the rest of the circuitry will be moot until you can convince yourself that the PIC's clock is running properly.



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    Member Khalid's Avatar
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    Dear All,
    I am just frustrated.. First i thought may be their some Traces problems or some component problems..Today i etched two PCB and mounted all the new components...

    I checked the first board in following way:
    1- JUMPER the ENABLE PIN (Pin-1 on IDC) to GROUND
    2- Provided +5V power to the PCB. The Gnd from the same Power supply also connected to the GND on PCB.(See the Picture)
    3- A seperate power supply (+24V DC) is connected to the Motor power connector. the GND from the same power supply is also connected to the Motor GND.

    4- The 4-wires from the motor is connected to other 4-connectors in a manner AA' and BB'.

    then i powered up the Board with both power supply but nothing happen. I checked the both power is being supplied to the board and i can read the voltages on PCB.

    I took a new PIC 16F628A and programmed it with following configuration bits:
    Oscilator type = HS

    Code protection (CP) = OFF
    Watchdogtimer (WDT) = ON
    (PWRT) = ON
    Low Voltage Programming (LVP) = OFF
    Brown out reset (BOREN) = ON
    (MCLR) = OFF

    and installed it on the PICSTEP in right direction but again nothing happen

    I then removed the 22PF capacitor across the xtal and replaced with 15PF capacitor but my motor do not hold...

    Please help me

    Attached Thumbnails Attached Thumbnails Reversed Logic voltage to PICSTEP- What component to be replaced?-picstep-jpg  
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    Quote Originally Posted by robe_uk View Post
    Hi
    I have not used the programmer you have but I would say yes select the correct PIC, fuses are set in the hex so you should not have to change anything there. You can download the firmware source code and compile it yourself, you can see it the code the different options the can be selected by commenting and uncommenting code.
    in which program i compile ? Alan has provided the Hex files, so should he inserted all the configuration bits in Hex?... Can you send me a Hex file so that i can upload?
    Quote Originally Posted by robe_uk View Post
    With the enable grounded you can put a pulse onto the step pin, when i originally built mine I just toggled the step input from +5v to 0v to +5v to 0v etc and the motor should step, although with microstepping you have to toggle a lot to see the motor move, if things are working correctly on the picstep once you toggle the input on the step pin the motors will hold provided the enable is 0v
    nothing happen.. Motor do not hold..
    My Question is :
    1- Should the Motor hold if the PIC is removed from the PICstep?
    2- If the enable is connected to Gnd and PIC is in the PICSTEP PCB socket, should the Motor Hold?

    http://free3dscans.blogspot.com/ http://my-woodcarving.blogspot.com/
    http://my-diysolarwind.blogspot.com/


  19. #19
    Community Moderator Al_The_Man's Avatar
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    Your Hex listing shows the config bits 3F46, this corresponds to your post #17.
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


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    Quote Originally Posted by Al_The_Man View Post
    Your Hex listing shows the config bits 3F46, this corresponds to your post #17.
    Al.
    Hi Al,
    how do you know that 3F46 is my configuration bits... Can you help me whats going wrong...pls

    http://free3dscans.blogspot.com/ http://my-woodcarving.blogspot.com/
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Reversed Logic voltage to PICSTEP- What component to be replaced?

Reversed Logic voltage to PICSTEP- What component to be replaced?