SOM Part Selection

USB-UART chip:

Goal: convert USB protocol to UART so our STM32 can read USB signals from a host computer
Current chip: CP2102N-Axx-xQFN24
- 4 dollars
- QFN package is hard to solder
- Works out of the box
Part selection requirements:
- Convert some protocol (does not need to be UART) to a USB protocol so we can plug a usb cable into it
- Needs to be cheap since we’re buying many of these for all SOMs ( > 5 dollars per chip)
- Supports micro USB
Alternatives:

Part Number	Cost ($)	Notes

Part Number

Cost ($)

Notes

FT230XS-R

2.26

Provides features we need, and supports 5V PWR.

A bunch of pins we probably won’t end up using

Hitlego CP2102N board

~2.5

Instead of a separate chip for UART debugging we buy a board that has. uart debugging chip and then make breakout pins on the SOMs
Saves cost and manufacturing time
Now requires an external dependency board to debug (what if we lose )

FT232H

4.09

Comes with a lot of features like supporting SPI, I2C, JTAG

Probably overkill considering we’re using this for USB debugging

Verdict
- It’s nice to have a USB chip on the SOM since we need less external boards
- FT230XS-R is the winner