Hi there, for a project I want to design a pcb which incldues an arduino pro mini (3.3V/8Mhz) and a LoRa Ra-02.
I’m very inexpert with schematics (but I’m trying to learn) and new to KiCad. What I’m trying to do is basically to simplify the arduino pro mini as much as possible but I’m not sure exactly of what I can/can’t remove.
The schematics I have are taken from here.
With my limited understand I’ve removed a few things (pretty much everything) except for:
- the crystal
- the C3 component between GND and VCC (no idea what is it for)
This is assuming that I will power directly the ATMega328 with a battery (ATMega Vcc accepts 1.8V - 5.5V from datasheet) likely 3.7V (for the LoRA module to work correctly).
The resulting schematic is below.
- can I remove the C3 component? What is it?
- Is it safe to use the battery directly to the ATMega or is it better to use something to protect the chip? In which case, what would I use?
- I see pins for Vcc (18,4,6) and GND (5,3,21) are all connected together. Is there a reason for it or can I just only connect 1 of each to Vcc and GND? for example disconnect pins 5,3 and 6,4, leaving only pin 18 to Vcc and 21 to GND.
Any comment is much appreciated!
FYI at the moment I have the LoRa working well with the arduino pro mini board so I’m basically trying to design a pcb to put everything together without cables (and smaller size).