PICkit 2 Constant "VDD Error"

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PICkit2Dev
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2006/09/28 13:41:38 (permalink)
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PICkit 2 Constant "VDD Error"


This error typically indicates a short or heavy load condition on the target board, including a part socketed backwards. If the error goes away when nothing is connected to the PICkit 2,
it indicates a likely target board problem and the information in this post is not relevant.
 
Older PICkit 2s produced before very early 2006 may be damaged by shorting the VDD output to ground, or pulling large currents out of the VDD pin.  PICkit 2's produced since then should not experience this problem.


Constantly getting the message "VDD Error" on software versions 1.20 and later, even when the PICkit 2 is not connected to any device is the prime symptom of damage. On older software, this issue would be seen as low VDD voltage when VDD was turned on but no device was connected. This causes programming to fail
unless an external power supply is used to power the part.
 

The damage can be fixed in most cases by replacing damaged diode D4 in the VDD path. Diode D4 is located near the button switch, by the "target" LED. The recommended replacement is the Zetex ZHCS1000TA, a high-current Schottky diode.

post edited by PICkit2Dev - 2007/04/10 11:30:23
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    xiaofan
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    RE: PICkit 2 Constant "VDD Error" 2006/09/28 13:57:42 (permalink)
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    ORIGINAL: PICkit2Dev

    Older PICkit 2s produced before very early 2006 may be damaged by shorting the VDD output to ground, or pulling large currents out of the VDD pin.  PICkit 2's produced since then should not experience this problem.



     
    What are the changes made for the PICKit 2 produced after that date? I am wondering it is only a bootloader firmware change or it involves hardware changes.
    #2
    PICkit2Dev
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    RE: PICkit 2 Constant "VDD Error" 2006/09/28 14:03:12 (permalink)
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    What are the changes made for the PICKit 2 produced after that date? I am wondering it is only a bootloader firmware change or it involves hardware changes.

     
    The bootloader is unchanged.  Firmware versions 1.20 and later will help prevent this issue even on older boards by detecting shorts and shutting off VDD.
     
    The production change was to use the ZHCS1000 diode for D4.
     
     
    #3
    16f877
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    RE: PICkit 2 Constant "VDD Error" 2006/10/10 03:07:32 (permalink)
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    PICkit2Dev, I meet the similar problem. When I connect PICTKit 2 and open the application file, it can find PICKit 2, but when I connect the board and select device, see the error: 
    PICKIT2 Vdd and Vpp Voltage Level Error Detected, Check Target & Retry Operation. 
    I check the
    ZHCS1000 with a multimeter and find it's ok, about 0.38v.
    Do you have any idea for me?
    #4
    PICkit2Dev
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    RE: PICkit 2 Constant "VDD Error" 2006/10/10 12:25:29 (permalink)
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    16F877,

    That you are seeing a "VPP Error" also, and that it doesn't appear when you start the application means it is unlikely the diode issue.
    Please check for the following reasons you might be seeing these errors:
    - Shorts on VDD and/or VPP (/MCLR), part socketed improperly, or PICkit 2 interface connection reversed/improperly wired.
    - Insufficient isolation of VPP signal from the rest of the /MCLR circuitry (see User's Guide)
    - Too much current draw from the PICkit 2.  If your circuit uses more than about 25mA, try powering it externally.
    - Too much capacitance on VDD.  If there is enough capacitance to slow the PICkit 2 VDD rise time to greater than 500us,
    it should be powered externally.
    - Trying to power a circuit that limits voltage above that voltage - ie trying to power a 3.3v circuit with protection Zeners at 5.0V.
    post edited by PICkit2Dev - 2006/10/10 12:27:22
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    16f877
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    RE: PICkit 2 Constant "VDD Error" 2006/10/10 19:03:13 (permalink)
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    Hi PICkit2Dev, I test with 2 PCs and 2 PICKit2s and 1 LPC board, let me mark them with PCa, PCb, PK2a, PK2b and LPC, and mark the VPP error as error.
    1. In PCa, PK2a + LPC, ok!  Pk2b + LPC, error!
    2. In PCb, PK2a + LPC, error!  Pk2b + LPC, error!
    3. In PCa, boot PICKit2 firmware with PK2a,i.e., PK2a + LPC, ok!, and then switch to Pk2b + LPC quickly, with no change to anything else,   ok!, but if select other device family and then change back to midrange, error!!!
    It's very strange! Thank you in advance!


         
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    16f877
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    RE: PICkit 2 Constant "VDD Error" 2006/10/10 21:04:16 (permalink)
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    Additionanly, I test again, and found my PICKit2 works fine with the firmware version of both 1.10 and 1.21, but the error comes when it goes to v2.01.
    #7
    PICkit2Dev
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    RE: PICkit 2 Constant "VDD Error" 2006/10/11 12:32:09 (permalink)
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    In v2.01, try setting VDD = 4.5V before connecting and attempting to program a device.  See if that works for you.
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    16f877
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    RE: PICkit 2 Constant "VDD Error" 2006/10/12 00:21:53 (permalink)
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    HiPICkit2Dev,  Now it's "PICKIT2 Vdd Voltage Level Error Detected, Check Target & Retry Operation.  "
    And I can't change the VDD manually because no device detected.
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    mmormota
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    RE: PICkit 2 Constant "VDD Error" 2006/10/13 03:10:53 (permalink)
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    ORIGINAL: 16f877
    And I can't change the VDD manually because no device detected.

     
    I am using the 2.01 sw and firmware version. Even if there is "no device detected" and "Vdd voltage error" warning present , it is possible to change the "Vdd Pickit2" voltage. If I set it to a lower voltage(ie 4V), and start a read or communication test, it detects the device and working properly. 
     
    This Vdd set in the program seems to be a treshold setup. If the actual Vdd is much lower then the set value, the program gives a "Vdd voltage error" warning and a "no device detected". The actual Vdd voltage provided by the Pickit2 is not affected, it is allways the USB supply voltage (4.6V on my PC) minus about 0.4V (the Schottky diode drop).  
    #10
    16f877
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    RE: PICkit 2 Constant "VDD Error" 2006/10/17 00:26:58 (permalink)
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    mmormota, I'm not so lucky as you are.
    Yes I can set the value of VDD before check the "ON", to 4.5 or something else, but it has no mean. For after I do so and select device family, the VDD error comes, and the value change back to 3.3 automatically. Or if I check "ON", the value change back to 3.3 automatically.

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    mrgone
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    RE: PICkit 2 Constant "VDD Error" 2006/11/10 09:52:57 (permalink)
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      OK, my PicKit2 has no problem with the 16F690 but I have hooked up a cable to the output connector so I can try to program a 10F206 chip. I get the "VDD error" and I scoped it out and it looks like all the signals are being loaded down. I have checked and re-checked the connections and according to the PicKit2 manual & the 10F2xx user's guide it is all correct. So I ordered a whole tube of 10F2xx chips & have same problem. I also have two "Low pin count Demo boards" and they both do the same thing. If I put the sample 16F690 back in it works fine.

    Here are my connections:

    PicKit2-------------->10F206
    (output conn)

    1---------------->8
    2---------------->2
    3---------------->7
    4---------------->5
    5---------------->4
    post edited by mrgone - 2006/11/10 09:56:02
    #12
    PICkit2Dev
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    RE: PICkit 2 Constant "VDD Error" 2006/11/13 16:45:31 (permalink)
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    The LPC Demo Board cannot be used with PIC10F DIP parts.  The 10F parts have a different pinout than PIC12F parts.
    #13
    dantlud
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    RE: PICkit 2 Constant "VDD Error" 2006/12/20 16:04:46 (permalink)
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    Hi,

    I get the VDD error when the PICkit 2 Programmer Target VDD source is set to Auto-Detect. When I set the source to Force Target, another error appears stating that the VPP voltage is incorrect. I am using V2.10 of the Programmer software, the board I am using is the PICDEM 2 Plus Board with a PIC16F877 as the processor.

    Can you suggest anything that will cure this problem?

    Thanks :)
    #14
    PICkit2Dev
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    RE: PICkit 2 Constant "VDD Error" 2006/12/20 17:58:44 (permalink)
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    dantlud,
     
    The PICDEM 2 Plus demo board draws too much current (and has too much capacitance on VDD) for the PICkit 2 to be able to power it.  If you power the PICDEM 2 plus with the 9 Volt DC wall adapter you should be able to use it with PICkit 2 without these problems.
    #15
    dantlud
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    RE: PICkit 2 Constant "VDD Error" 2006/12/22 10:45:44 (permalink)
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    I am now using a 9V wall adapter, but the error persists. Only when I select Tools -> Target VDD Source -> Force Target the error window for VDD disappears. However, I get a different error complaining that the voltage on VPP is incorrect. 
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    PICkit2Dev
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    RE: PICkit 2 Constant "VDD Error" 2006/12/22 15:41:03 (permalink)
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    I am now using a 9V wall adapter, but the error persists. Only when I select Tools -> Target VDD Source -> Force Target the error window for VDD disappears. However, I get a different error complaining that the voltage on VPP is incorrect.

     
    This sounds like there may be a wiring problem between the PICkit 2 and PICDem 2+.  How are they connected?  The PICkit 2 should detect the PICDem 2+ VDD when connected properly.
     
    In PICkit 2 v2.10, you can used the Tools > Troubleshoot... wizard to verify each signal is getting to the appropriate pin on the 16F877.
    #17
    dantlud
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    RE: PICkit 2 Constant "VDD Error" 2006/12/23 13:41:15 (permalink)
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    The PICkit2 connects to the board using the Microchip part no. AC162069 cable. The RJ11 end is plugged into the ICD board socket, and the pins into the PICkit2. When I used the Troubleshoot tool it informed me that I had to supply 4.5V from the PICkit2 in order to get the correct VDD level. Once set, VPP was correct at 11.9V. However, when I toggled PGC and PCD low and high, the voltage on these pins did not change.

    Hope that's helpful.
    #18
    PICkit2Dev
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    RE: PICkit 2 Constant "VDD Error" 2006/12/23 17:48:13 (permalink)
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    dantlud,
     
    The AC162069 ICD 2 breakout cable cannot be used in this way.  If you look at section 9.3.3 of the ICD 2 User's Guide you'll notice that the cable is straight through.  What this means is that the ICD 2 RJ-11 is wired backwards from a target or demo board RJ-11.  This cable is meant to be plugged into the ICD 2 RJ-11 and the pins connect to the target.
    When you plug the AC162069 into the target board, the signal descriptions for the flying leads don't make sense, because they will be in reverse order.
    You would not be able to get it to work by flipping the flying leads around because there only 5 leads, so there will be no connection for VPP into the target board.
    Instead, you would need the AC164110 - RJ-11 to ICSP Adapter.
    #19
    dantlud
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    RE: PICkit 2 Constant "VDD Error" 2006/12/24 04:36:18 (permalink)
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    Oops! Very sorry about that. Thanks for explaining why it doesn't work. I'll be getting the correct cable in the near future. Thanks for all your help and have a good Christmas :)
    #20
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