I'm adding a usb to a PCB I'm making for the first time with the ATmega chip. The 'standalone' arduino.
As part of my project, I have a 5V 10A power supply to run a bunch of LEDs and other components.
But I want to add USB functionality.
Question 1: The FTDI boards you can buy have the 5V power pin. My understanding is that is 5V OUT, to give power to the board/chip when connected to USB. If I already have a separate 5V power source supplying my chip/board, should I leave the 5V unconnected on the USB FTDI board? Or should I still connect it up. I feel like the chip would be getting TWO power sources at that point and that that would be bad. So with external power, do I still connect the 5V line on the chip?
Question 2: The DTR pin connects to pin 1 of the 328 chip for reset, through a capacitor (I'm using 0.1 uF). Can I also add a reset switch at the same place? So basically pin1-->0.1uF-->DTR and then pin1-->same 0.1uF-->spst switch?
Or can only one thing be connected to the reset switch? If I add the button, then when pressed it will also connect DTR to ground as well as the pin1.
I should mention I do have the 10k pullup resistor on pin1 as well.
edit: I've seen one board suggesting for question #2 that you CAN add a button as well. But that the button does NOT go through the capacitor. Does that sound right?