USB / Serial Bridge Options

I’ve been working with FT2323H USB to Serial device. I have a need for both USB/I2C as well as USB/UART with some general purpose I/O. I like the FT232 because it gives you all of these features, but doesn’t require you to write custom firmware and program it to the chip (like a USB microcontroller would). Having some trouble communicating with this device using a .NET app running on Linux (.net software libraries are built for Windows only).

Started looking for other options with software libraries that will work for both Linux or Windows and came across MCP2221. Seems like a pretty solid solution. Supports both USB to UART and USB to I2C. Has a few GPIO to work with. Found a few different .NET libraries to work with which is nice. However, this chip doesn’t provide much for UART configurability beyond the baud rate which disqualifies this from our solution (need EVEN parity).

Wondering if there are any other potential options similar to FT232 or MCP2221 that I haven’t stumbled across yet? Need USB to I2C, USB to UART, and at least 3 GPIO to work with. Obviously, I could use a USB microcontroller, but I’m trying to avoid the requirement of writing custom firmware as that is just one more support obligation we would be taking on for this product.

Welcome to the TechForum, I am looking into your question.

Hey @scott.schmit ! Long time…

Thinking maybe… GitHub - smdn/Smdn.Devices.MCP2221: .NET library for controlling MCP2221/MCP2221A USB2.0 to I2C/UART Protocol Converter with GPIO


Hey @scott.schmit,

Have you taken a look at any of the Cypress/Infineon CY7C652xx series stuff. It appears that they handle I2C, UART with parity, and have plenty of GPIO. It’s a bit difficult to differentiate between the various models and not sure just yet what sort of software support is available (I’ll see what I can find). Unfortunately, as per current supply issues, almost nothing in stock at the moment, but still might be worth a look.

We also have eval boards available for a few variants.

Hey Rob! Great to hear from you! I actually saw that .net library already. I like the .net software library options for the Microchip part as I intend to communicate with the device from a .net core web app (able to run on Windows and Linux). Looks like Microchip has its own library as well, although it doesn’t appear to work for Linux environments. Actually, there’s not much that I don’t like about the Microchip part. Unfortunately, the inability to set UART parity is a deal breaker for us as one of our primary serial targets for this bridge device uses EVEN parity, so I think the MCP2221 is probably not an option.

@David_1528, I was wondering when someone was going to bring up Cypress :slight_smile:
I suspect this chip would fit what we want to do at a hardware level (where the Microchip part comes up short). Scanning some of the USB driver / .net library documentation. I worry a little about getting that driver working with a linux-hosted .net webapp. I’ll do some more digging though. Thanks for finding this!