Why?

A bunch of random UART converters

I am a computer and electronics engineer. I am a hardware hacker and maker.

USB-UART converters are ubiquitous and can be used throughout many phases of a product's lifecycle. They are used during initial board bringup, for debugging and development, for flashing firmware, for exchanging operational data, as service ports in the field, or as diagnostic interfaces during analysis.

As many as they may be, these use cases don't really differ much from a hardware perspective, so I thought to myself - Why do I need multiple converters just to get all voltage levels for different projects? Why do I need multiple of each just to get all the pins for flashing here or handshaking there? Why won't many of them last, and why do some act up time to time? As it stands, I need a small collection of these adapters, each of them less then ideal, and I still have use cases not covered.

A USB-UART converter is my tool, and I want to debug my project, not my tools. My tool should be reliable. Such adapters are often used during development, experimentation, or debugging, and especially on these occasions, mistakes and accidents happen. As a result, my tool should be robust and it should isolate faults. A USB-UART adapter is also used throughout a project's lifetime and during many projects, so it should lend itself easily to multiple similar use cases. Hence, my tool should be versatile and universal. Other converters on the market were made to be simple or to compete in price. I want quality naturally combined with functionality.

The muArt

The muArt UART converter

The μArt - as in mu-art - is a USB-UART adapter (also called serial converter) for TTL-level signals, finally done right. It was made to be versatile, robust, and reliable. It has all the pins and features to enable various use cases, all the protections to withstand or even prevent faults, means to preserve signal integrity, and a number of features to improve usability. Let the following list speak for itself:

  • Wide working voltage of 1.8 to 5.4 V, making it suitable for most projects, be it single-board computers, microcontrollers, FPGAs, or low-power electronics.
  • RXD, TXD, DTR, RTS, and CTS. Usable not just for basic communication, but also for flashing various modules from Espressif and multiple Arduinos such as the Pro Mini, Fio, or Arduino Pro. Hardware handshaking allows for reliable high-speed UART.
  • Up to 3 Mbaud transfer speed, the highest in the industry. As an example, this is enough bandwidth to stream uncompressed high-quality stereo audio.
  • Complete galvanic isolation, even for mains-level and higher voltages. Electric currents cannot flow between your computer and the other board. This spells safety for you and your computer, while also helping to keep noise levels down.
  • Reverse polarity protection. The converter will survive even if you mix up the power pins.
  • Over-current protection on IO pins. Made a false IO connection by mistake? Don’t worry, the μArt and your other board are both safe.
  • Pullups on all inputs, so that disconnected pins don’t cause funny things like garbage random input, a ruined terminal app, or corrupt application state.
  • Judicious filtering. Each IC in the converter is decoupled using multiple capacitors, both locally and in bulk. The USB signals and power are filtered, and sensitive pins are protected with RC networks.
  • Multi-level ESD protection for all external pins. ESD damage is tricky because things can seem to work for a while after an ESD event, and you don’t need visible sparks to have it.
The muArt UART adapter board
  • Voltage auto-sensing, meaning the converter will automatically use the correct voltage levels for UART communication. No more setting jumpers or “Which of these 5 converter boards was the one for 3V3?”.
  • Cross-platform support, with readily available and mature drivers for Windows, Linux, MacOS, and more.
  • Suitable for communicating with low-noise circuits, supported by the filters, the isolation, and careful layout.
  • GPIO pins that you can control directly over USB, parallel to the UART lines. They can also be reconfigured in software for alternate functions (TXDEN for RS-485).
  • Four LEDs, each of different color to make them immediately distinguishable. One lights up if power is connected, two indicate RX/TX activity, while the last one is connected to a GPIO, giving you visual feedback about its state without special software on the host computer.
  • Four-wall shrouded header gives protection from ESD by fingers and from shorts by dangling wires.
  • Custom-designed, professional, and ergonomic case, giving both mechanical and electrical protection, and a cool transparent-translucent look.
  • Compact design, only the size of two euro-coins.
  • CE- and FCC-compliant, independently lab-tested.

Resources

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The μArt is preparing for its first production batch. Support the product on Crowd Supply now, and be one of the first ones to receive a unit. For more information, mailing list for related announcements, and support options, click below.

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