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Author Topic: PICkit 3 VDD Calibration?  (Read 6587 times)

eugge

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PICkit 3 VDD Calibration?
« on: October 31, 2016, 02:15:08 PM »
Hi!
I've bought recently a PICkit 3.
I was trying to program a PIC32MX250F128D without success.
This is the MPLAB output information:
Connecting to MPLAB PICkit 3...

Currently loaded firmware on PICkit 3
Firmware Suite Version.....01.44.26
Firmware type..............PIC32MX

PICkit 3 is trying to supply 3,250000 volts from the USB port, but the target VDD is measured to be 3,000000 volts. This could be due to the USB port power capabilities or the target circuitry affecting the measured VDD.

The target circuit may require more power than the debug tool can provide. An external power supply might be necessary.
Connection Failed.
- - -

I measured voltage level between pin 2 and 3 on PICkit 3 and saw 2,97V. If I disconnect the programming cable from board I see 3,07V. How come? In power settings it is set 3,25V.
There is any callibration tool for PICkit 3 VDD ? Or what I'm doing wrong?

I tried on different MPLAB versions but still see the voltage difference about 0,3V between real output and set in power parameter.
Also I tryed PICkit 3 with external power suplyer 7V and still see the same "low" VDD on output pins.

JohnS

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Re: PICkit 3 VDD Calibration?
« Reply #1 on: October 31, 2016, 07:32:40 PM »
I usually find it can't provide power so use a separate supply.

John

eugge

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Re: PICkit 3 VDD Calibration?
« Reply #2 on: October 31, 2016, 10:12:11 PM »
I usually find it can't provide power so use a separate supply.

John
Do you mean a separate supply to PCB or to programmer (pickit 3)?

Of course I tried to use a separate Power supply to PCB and the programming went well (just to check that programmer itself works).
The main problem is that I need to programm in the field, with minimal cables and connections, that's why it is important to provide on pickit 3 output "exact" VDD.
I could suppose that the PC USB current is not enough but even I connect an external supplyer to PICkit still it doesn't provide right VDD.
The output voltage is too low even when I disconnect PICkit 3 from PCB (nothing to do with current consumption).

My guess is that the problem with VDD calibration from old PICkit 2 migrated to new one...
Hope to get a real support in my problem.

JohnS

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Re: PICkit 3 VDD Calibration?
« Reply #3 on: November 02, 2016, 01:49:00 PM »
In field I always have power on the target.  Never from Pickit3.

John

eugge

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Re: PICkit 3 VDD Calibration?
« Reply #4 on: November 03, 2016, 12:36:30 PM »
In field I always have power on the target.  Never from Pickit3.

John
In the field I'm trying to have minimum of cables and connections, it minimizes the chance to connect something wrong.
Of course everybody is choosing the easiest method...
Meanwhile I got some advises from Olimex support and the result is below:

 I played a little bit with voltage (power) settings.
- In MPLAB X IDE v3.45 and MPLAB X IPE v3.45 the maximum voltage limit for my target chip is 3,5 V. When I set it, the "real" output voltage is 3,25 V (accordind to MPLAB) and I get the same error "... The target circuit may require more power than the debug tool can provide. An external power supply might be necessary.
Connection Failed."
- In MPLAB IDE v8.92 the maximum voltage limit for my target chip is 3,599 V. When I set it, the "real" output voltage is 3,25 V (accordind to MPLAB) and the read/program process is going well without errors. Even I minimize the voltage limit to 3,458 (in settings) and get the output 3,13 V still the read/program process is going well.

To summarize, even the PICKit3 (hardware+firmware) has voltage issue, the MPLAB IDE v8.92 doesn't care and doing well the job.

I will use the working combination until is coming the fix for MPLAB X or/and PICKit3.