VPP Voltage Error

[yklyman]

Hello,

I am attempting to program a PIC12F1571 and I have 3 wires connected to the output of the programmer's MCLR/Data/Clk pins connected to a circuit board attached to my PIC chip. I am attempting to program the board and an error pops up indicating VPP Voltage Error (4.22 volts). The data sheet for the PIC 12 indicates the MCLR Line should toggle high between 8 and 9 volts. I have the MCLR pin metered and it reads 3.22V. Is there some setting I should be aware of that will affect this?
I attached my project for your ease.
Thanks!

[biljana.nedeljkovic]

Hello,

please check the electrical characteristics of your microcontroller:
http://ww1.microchip.com/downloads/en/D ... 01723b.pdf

Can you tell me which hardware do you use with your PIC?
Can you send me the photos of your connections?
You should disconnect all the peripherals like displays, diodes etc, and then try to program.
Have you connected power supply and GND? What is your power supply voltage?

Best regards,
Biljana

[yklyman]

Thank you for your reply.

I have confirmed the electrical ratings for the chip are within appropriate ranges.

I am attempting to program the PIC without any peripherals connected and have attempted two kinds of programming. 1) Only connecting the MCLR/Data/Clock lines to the chip from the programmer. 2) Connecting all lines from a regulated 5v supply.

Do the programmers Vdd and gnd need to be connected when I programming the chip?
Can I not simply connect the MCLR/Data/Clock pins to the chip?

[yklyman]

I read further into the documentation and came to the conclusion that I need to have the chip powered during programming. I wired it appropriately and am still having the VPP problem. Is it possible the programmer is broken and not providing enough voltage?

[biljana.nedeljkovic]

Hello,

which programmer do you have?
Please send me the photos of your connections.

You need to power the chip and also connect the power supply and GND on the programmer.
After you tried to program the chip, have you noticed if the chip gets overheated? Are you certain it's functional? Have you been able to program it before?

Best regards,
Biljana

[jpc]

maybe a stupid suggestion but you say :

I have 3 wires connected

, where is the ground connection?

[yklyman]

I have connected the MCU_VCC to my 5v supply with no success and have the supply lines connected to the same supply and the return lines grounded.

[yklyman]

I am use the MikroElectronica programmer

live image link at
http://imgur.com/6bW8lIR

[biljana.nedeljkovic]

Hello,

how do you supply the microcontroller? Do you have two power supplies?
I have successfully programmed the microcontroller with 3.27 volts on MCLR pin but I have supplied both PIC and programmer.

Best regards,
Biljana

[yklyman]

Hello,
I supply the programmer and circuit with 5v and I tried supplying the MCLR pin with 5v and 8v.
Can you send me your circuit diagram and I will attempt to wire my system the way you have?
Thanks!

[hadv]

If you use two supplies make sure they have a common ground.

[yklyman]

Thank you for your input.
When I attempted using two supplies, I did use a common ground.
Is there anything else that I might be missing?

[hadv]

As a matter of fact I do. I read your posts again and then it came to my mind that you powered the board from a separate supply.
Let me make it clear that I do not know the programmer you use (I use PicKit2/3), but a programmer should supply all five lines necessary to program a PIC (+5, Vpp, Clk, Dat, Gnd).
I took a look at the documentation and found this to be the case.
Using only three pins to the programmer, and +5 and gnd from a different supply will not work because the programmer is not connected so it won't be able to give a sensible voltage reading.

So...connect all 5 lines to the programmer and forget about the external power supply.

[yklyman]

Thank you again for your help hadv.
I am using the MikroE PIC programmer.
So I connect the MCU-VCC pin out from the programmer to the MCLR and VCC lines on the PIC and the GRD pin out from the programmer to the PIC ground lines? No external power supply is needed?
If its not too much trouble, could you provide me with a circuit diagram? The ones I have seen seem to indicate the connection of an external supply but it is possible I am misreading them.

[hadv]

It should be in the documentation. I defnitely found it there & it can be found on the mE website.