Looks like it just needs to short to ground to work. Is it a pull-up circuit, or do I need to use a resistor?
Please provide some more details? Are you designing your own board?
This is from the schematic of an Uno rev3
The line at the left of C5 goes to the 16U2 (DTR signal). The resistor in the schematic is the pullup.
I will be building a shield that will hide the main reset button, but I want to retain the functionality. So I will be adding a reset button to the shield.
I'm a bit fuzzy on circuit logic and concepts, but am working my way through. I'm building some successful projects on my breadboards, and am moving toward putting some of them on PCB shields.
Based on your schematic, it looks like there's a diode in parallel with the resistor. Does that prevent reverse voltage on the reset pin?
Provides a discharge path for the capacitor.
If you are building a shield you only need the button as the circuitry is still on the Arduino
(Capacitor and diode are there to support programming the board to create a pulse ( from DTR ) to reset the processor prior to uploads .) . The diode blocks any negative voltage so generated .
And also blocks the positive spike to 0.7V protecting the RESET/-pin of the MCU.
1 Like
What’s wrong with just adding it in parallel?
Nothing , that is what has been explained to the OP
What is wrong if the capa is not there in a stand alone design?
Yes but we have already established this is not a stand alone design, it is for a shield and so the capacitor IS there.
On the promini board I simply take it to ground.....
https://www.arduino.cc/en/uploads/Main/Arduino-Pro-Mini-schematic.pdf
This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.