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I was looking to use a PIC32MX series microcontroller on a project. It is currently in the mail, but I thought I would try to understand the wiring for power and programming before it arrived. I had planned on using a PICKit 3 to program the device over the ICSP line, but I'm having some trouble understanding the wiring of the MCLR. Here are the designs I have come across:

schematic

simulate this circuit – Schematic created using CircuitLab

According to Figure 2-2 on page 46 of the reference manual for the device family the connection circuit should look something like the first circuit design. According to the Microchip wiki it should look like the second circuit. The third design comes from Figure 2-4 in the PICKit 3 User's Guide and the final design comes from Figure 1 in the Microchip ICSP Guide. The design I have seen most people using is the third one, but I am unsure if it would be better for some reason to use one of the others. Does anyone have a suggestion?

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  • \$\begingroup\$ I edited your question to include your links. (was waiting for edit approval to comment) Welcome to EE.SE! \$\endgroup\$ – user2943160 Aug 15 '16 at 1:25
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I believe in the past I have used Option 1, although all of them will probably work ok.

The advantage of Option 1 is that it is the most protected from ESD and other transients on the programmer reset pin and the switch.


Option 4 is intended for the case where the programmer is providing a high \$V_{PP}\$ (possibly 13V) to the \$\overline{MCLR}\$ line.

Related: ICSP Circuit: Vpp (13V) and Vdd (5V) on Pic microcontroller MCLR pin

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I am using option 3, just because it is simplest.

But here I combined options 1 and 4:

schematic

simulate this circuit – Schematic created using CircuitLab

It combines ESD protection (from option 1), and blocks 13V to get to Vdd (from option 4)

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