Trouble with USB to SPI , finding a good ic

I want to be able to program my ATmega using the arduino IDE . I know that this can be done with SPI
So I need a USB to SPI ic converter for this project ? Most arduinos use FT232RL but this chip is for USB to UART conversion . I am really confused right now :confused: ... Is there a way that UART signal can program an ATmega ? Also I found an ic for USB to SPI conversion , the MCP2210 . Is this ic okay for my project?

You actually want to program it using ISP (In-System Programming), which does use the SPI pins but is different to SPI. There are a variety of ISP programmers- the USBASP is a fairly popular one and you can get them fairly cheap from a variety of places.

I m interested in making my own programmer:/ ... So I need you to give me links for some ics that wont give me a severe headache

Most arduinos use FT232RL but this chip is for USB to UART conversion

Incorrect on both points. The Uno and Mega, the most common boards with a USB input use the ATmega16U2 for USB to serial conversion using public domain firmware. The Chinese clones use the much lower cost dedicated CH340G.

You can use a repurposed Uno or Nano board using the Arduino as ISP program but if you want a dedicated solution, the most common chip used for a stand-alone ISP programmer is the ATmega8 as used by the open source project USBasp. This project has been copied by the Chinese and is available on eBay for about $2 US. FWIW, you cannot buy the parts for that cost. Be sure to buy a 10 pin to 6 pin adapter so it will plug directly on the Arduino boards.