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Pro Micro hardware modification clarification #2

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hiduino opened this issue Aug 31, 2019 · 4 comments
Closed

Pro Micro hardware modification clarification #2

hiduino opened this issue Aug 31, 2019 · 4 comments

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@hiduino
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hiduino commented Aug 31, 2019

Can you clarify the hardware modification? It appears that pin-1 (in the picture example) of the regulator is the RAW input, not the 5V output pin.

@MCUdude
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MCUdude commented Aug 31, 2019

It is indeed connected to the VIN pin, However, since microUPDI requires a 5V 16 MHz Pro Mini, this means that the solder jumper (SJ1 in the Pro Micro schematics is shorted, and ~4.5V will appear on the VIN pin.

I chose that connection point because it's the closest to the AREF capacitor. However, you may choose any 5V point on the board if you like.

@hiduino
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hiduino commented Aug 31, 2019

Yes, thanks for the clarification. I think it will be safer to go with the 5V output, just in case someone decides to put in more than 5.5V on the raw input (not that anyone would but you never know).

@MCUdude
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MCUdude commented Aug 31, 2019

I think it will be safer to go with the 5V output, just in case someone decides to put in more than 5.5V on the raw input (not that anyone would but you never know).

There's no reason to connect the Raw pin to anything when using the Pro Micro as a UPDI programmer. I'll leave a note that the Raw pin shouldn't be used.

@MCUdude
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MCUdude commented Oct 19, 2020

The latest release (v1.0.1) uses a modified firmware where the hardware modification is no longer necessary since AREF is connected to VCC internally instead

@MCUdude MCUdude closed this as completed Oct 19, 2020
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@MCUdude @hiduino and others