A simple implementation of serial communication between two software entities (Uart / I2C / etc.)

Question

I've done many projects that include a PC & an arduino / PLC / some kind of other microcontroller / processor, and in every project we had a different protocol used for communication between the PC application and the embedded one. Usually the hardware / controller developer invents a simple protocol which always changes throughout the project, and goes into the form of

Barker | Size | Data | Checksum

This time I'm implementing both sides, so I figured - This has been done a million times before. There must be a base protocol for these things with implementations in C, C#, Java, and such. What I'm looking for is a lightweight layer that transfers stream based serial communication into a message based one.

I've been looking around for one for a while, but I couldn't find anything on my own. Do you happen to know one?

Answer 1

I had exactly the same requirements for a recent project and I found nothing simple enough for low-end 8-bit microcontrollers. So I designed MIN (Microcontroller Interconnect Network) to do the job (inspired by CAN and LIN).

The code is on github here: https://github.com/min-protocol/min (check out the wiki there).

I defined a layer 0 (the UART settings) and layer 1 (the frame layer, with checksums, etc.) plus a C API.

I'm also working on a higher layer that formally defines how sensor data (temperature, pressure, voltage, etc.) are packed, with a JSON representation and a tool to autogenerate the embedded code to pack/unpack them from frames. The end goal is to create a Wireshark dissector that can be clipped on to the serial line and when fed with the JSON will display the signals in human-readable form.

I wrote a blog post showing a Hello World app running on an Arduino board (with an FTDI UART-USB breakout board carrying the data up to my host PC):

https://kentindell.wordpress.com/2015/02/18/micrcontroller-interconnect-network-min-version-1-0/

This serial problem occurs so often that it would be nice if we as a community just nailed it rather than keep re-coding it for every project.

Answer 2

Check Open Source HDLC

I recently came across MIN - never used this one though

Also check this Simple serial point-to-point communication protocol

Answer 3

Using X/Y/Z MODEM protocol must be a good choice to solve your problem. It's easy to implement and ready-to-use. I use X-MODEM on an ISP tool communicates with our cortex-m0 powered MCU, and it works pretty well.