NOYITO CH341A USB Bus Converter Module USB to Serial Module RS232 RS485 RS422 Programmer

This is a great board because the design makes it more configurable compared to other boards with this chip. At the very least you need to solder on the headers, and then jumper either 3.3V or 5V to VCC in order for the chip to power up and operate. I set mine up with a breadboard so that I can connect and jumper pins as needed. This board doesn't come with any instructions, but if you do some searching for the CH341A datasheet it is easy enough to figure out. The Mini-USB port was a great design choice as well, I prefer it over the more popular Micro-USB ports that tend to be too fragile.

This was a bit of a puzzle because of no documentation.I found that for my application (Asynchronous Serial), it was necessary to jumper VCC to +5V, and also TEN to GND (to enable the Tx function). Also, according to the device data sheet, "V3" shoild have a decoupling capacitor to GND when operating with a 5V supply.