The humble USB-UART adapter. Such a ubiquitous device, there really isn't much to say about it. If you don't know what it is, you probably don't need one, and if you do know what it is, you probably already have 3 of them scattered around your desk somewhere. These things get practically handed out for free with any dev board out there. Sadly, though, that commoditization has come at one significant cost: quality. These devices are so common, and so cheap, they've ended up in a complete race to the bottom, and nobody really bothers to make GOOD ones. Many years ago, I bought an adapter called the FTDI Pro, made by ckdevices, and it has been my go-to adapter ever since, because they took the time to pay attention to the details in their design. Sadly, it seems that ckdevices is no more, and their FTDI Pro is no longer available anywhere, so I took it upon myself to take what they did right and update the design along the way. The USB mini-B connector from the FTDI Pro (a far superior choice over the commonly used micro-B) has been replaced with USB-C, and the classic FT232RL has been replaced with the newer and more capable CH340C.

Features:

• Up to 2Mbaud communication speed
• Supports 5V and 3.3V operation (150mA maximum in 3.3V mode)
• Pinout follows standard FTDI cable definitions
• Low-profile USB-C connector (USB2.0-only)
• On-board 3.3V voltage regulator, with physical switch (no solder jumpers!)
• Physical switch to swap Rx/Tx pins, allowing direct communication between two adapters.
• LED indicators for operating voltage and I/O activity
• Unique serial number and product ID to avoid system level conflicts with other CH340 devices, allowing multiple devices to be used at once