I am making a programmer for my atmega ics but I dont know what interface to use to communicate with it...
I see USB to FULL UART , BASIC UART , SPI , I2C , FIFO ( no idea what this is , sounds like a candy brand name) , and I dont know what to choose.
Any ideas?

 

I am making a programmer for my atmega ics but I dont know what interface to use to communicate with it...
I see USB to FULL UART , BASIC UART , SPI , I2C , FIFO ( no idea what this is , sounds like a candy brand name) , and I dont know what to choose.
Any ideas?

Read Chapter 32 Section 9 of attached datasheet. It has the circuit, the voltages and step by step instructions of what needs to be done to program the ic using serial (USB, universal SERIAL bus) system/signals.

 

Found this online but there are more FT232 chips . FT232BL , FT232RL , FT232HL , FT232RL-TUBE . Which one should I choose? Also I found this chip :http://www.acdcshop.gr/content/mcp2221.pdf (datasheet) , https://www.microchip.com/wwwproducts/en/MCP2221 (actual chip)
Should I go with this option? It has both I2C and UART and less pins + it is THT mounted (I have no SMD experience) , also it has less pins for me to get troubled with . What should I pick?

 

Found this online but there are more FT232 chips . FT232BL , FT232RL , FT232HL , FT232RL-TUBE . Which one should I choose? Also I found this chip :http://www.acdcshop.gr/content/mcp2221.pdf (datasheet) , https://www.microchip.com/wwwproducts/en/MCP2221 (actual chip)
Should I go with this option? It has both I2C and UART and less pins + it is THT mounted (I have no SMD experience) , also it has less pins for me to get troubled with . What should I pick?

Atmega328 uses spi for serial programming.

I think there is one case where it uses uart. You did not mention it.

 

Found this : https://www.acdcshop.gr/content/DS_FT311D.pdf
Is it okay ? Both UART , I2C and SPI