Hi! I am designing a pcb and would like to know what components are required to use an ATmega328p-pu like an Arduino Uno for bootloading, uploading, and running code. Anyone know?
Funny you should ask that - I have a 328P-PU in front of me on a breadboard right now that I’m programming to be a very low energy data monitor for a mobile fridge and freezer. I am using a USB ASP to program it and since it doesn’t need high-speed I have loaded a 8MHz bootloader using the internal oscillator to save parts. I have a pull-up resistor on the reset (which isn’t 100% necessary, but safe) and also 2 small and one larger decoupling capacitors, which again aren’t absolutely necessary. I am using I2C to connect to a BME680 and some I2C FRAM so have those two chips plus 2 pull-up resistors for I2C.
It is possible to run an ATMega328P-PU without any external components apart from a ISP Programmer. My breadboard is doing serial at a TTL level to another Arduino, but if you want serial to a USB you would need an external UART chip (like the FTDI chip) for communications.
There was a good article on breadboarding this chip, let me search for it again, ahh, there it was - Nick Gammon’s page at https://www.gammon.com.au/bootloader
Ok, I will try that. Thanks.