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Forum Index : Microcontroller and PC projects : PIC Programming voltage Vpp - alert

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larny
Guru

Joined: 31/10/2011
Location: Australia
Posts: 346

Posted: 11:49am 29 Dec 2014

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I recently discovered - by looking at some of the files in the MPLAB IDE Device folder (see Program Files (x86)\Microchip\MPLAB IDE\Device) - that the nominal programming voltage (Vpp) is not always 13 Volt. Some examples (taken from the respective .dev files) are shown below - note that the PIC 16F684 is 11 Volt nominal with a maximum of 12 Volt!

PIC16F84
vpp (range=12.000-14.000 dflt=13.000)

PIC16F88
vpp (range=12.500-13.500 dflt=13.000)

PIC12F675
vpp (range=12.750-13.250 dflt=13.000)

PIC16F684
vpp (range=10.000-12.000 dflt=11.000)

PIC16F917
vpp (range=10.000-12.000 dflt=11.000)

All of the PIC programming hardware I have seen was designed to apply about 13 Volt. So I don�t know what would happen if one of these was used to programme a 16F684. But I don't intend to find out!

I recently purchased three of these PICs so I will modify one of my programmers so I can switch it between 11 and 13 Volt using a jumper shunt.

One of the programmers I constructed is the dSPIC/PIC Programmer published by Silicon Chip in their May 2008 issue. This one covers a wide range of PICs & it will be easy to modify. So I will do it in the new year and post the details in this forum.

Edit. I have just checked 2 more PICs & added them to the list above. Note that the 917 is also 11 Volt nominal.Edited by larny 2014-12-30

MOBI
Guru

Joined: 02/12/2012
Location: Australia
Posts: 819

Posted: 11:32am 30 Dec 2014

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Hi,

I have been using the SiliconChip PIC programmer for years now on all manner of chips. The programmer VPP is 13VDC. So far, I have not damaged any PICs.

I am making my own programmer and intend to make the VPP adjustable.

David M.

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