BeagleBoard/GSoC/BeagleBone-based-Serial-Terminal-Server

=BeagleBone based Serial Terminal Server =

Student: Harikrishnan R Mentors: Michael Welling Code: GitHub: BeagleBone based Serial Terminal Server Wiki: eLinux: BeagleBone based Serial Terminal Server GSoC: TBD

=Status= This project is currently just a proposal.

=Proposal=

About me
IRC: illustris Github: https://github.com/illustris School: BITS Pilani, Goa campus Country: India Primary language: English Typical work hours: 11:30 PM to 4.30 PM UTC Previous GSoC participation: No previous participation.

About my project
Project name:   BeagleBone based Serial Terminal Server Task Completion: Pull request.

Description
Often in embedded development it is valuable to have a serial terminal server which can retain a serial port connection along with buffered past I/O separate from a typical host PC, either for longer term logging of serial port data or to enable remote management of a device via serial port. Commercial units which have this capability are very expensive, with even single port serial terminal servers consting hundreds of dollars. The BeagleBone has 4 highly capable UARTs exposed besides UART0 through the cape connectors. A simple cape hardware could easily enable a BeagleBone to physically have all the interfaces needed to be a serial terminal server.

Deliverables
The project will have the following features:
 * 1) User connects to the terminal server over SSH.
 * 2) A command line interface will allow users to configure and select the interfaces to monitor and log.
 * 3) Logs will be split and archived every 24 hours.
 * 4) User will be able to attach to and detach from individual serial terminal sessions, similar to tmux/screen.
 * 5) User will be able to view logged data from the serial device.
 * 6) Kermit style expect-send scripts can be attached to interfaces from the prompt.
 * 7) Arbitrary scripts/executables can be attached to interfaces for automation through redirection of stdio.
 * 8) Scripts can be scheduled for periodically connecting to devices, performing actions and logging the output.
 * 9) The final goal of this project is to provide a ready to use serial terminal server image for beaglebone, and to provide instructions for building an image with the latest version of debian

Implementation

 * A new user will be added to the BeagleBone for users to connect to.
 * The new user will have a custom prompt instead of bash.
 * termios will be used to configure serial interfaces.
 * Incoming data will be piped to a log file without buffering.
 * When a user attaches to a session, the log will be tailed to display the serial output.
 * Input from the user will be piped to the serial device in interactive mode.
 * A cron job will handle log archiving.
 * The native "expect" program will be used to parse expect scripts.
 * On running a script, the output of UART will be piped to the script, and the output of the script will be piped to UART.
 * scheduling of scripts will be handled by a separate thread.

Resources

 * Serial cape design by pmezydlo
 * KiCAD tutorials
 * Wikipedia page with example expect scripts
 * Enabling all UARTs on BBB
 * handling SIGINT
 * Tab completion using readline
 * Using inotify for efficient unbuffered tailing of log files
 * example of piping stdio in C

Experience and approach
I'm a final year undergraduate student at BITS Pilani KK Birla Goa campus. I've worked on a few embedded systems projects including Hyperloop India, the student team that was one of the 24 finalists (one of two from Asia) in the 2017 SpaceX Hyperloop pod competition. As the controls engineering lead of Hyperloop India, I have worked extensively with embedded electronics and software. One of the nodes used in the pod electronics was built around a BeagleBone with a device tree overlay for enabling DCAN1. I have also ported FreeRTOS to a RISC-V processor I helped design.

Contingency
What will you do if you get stuck on your project and your mentor isn’t around? If Michael and Stephanie are unavailable, I would try asking for help on IRC. I would also consult relevant manpages and documentation.

Benefit
This project will allow users to monitor up to 4 UART devices over ethernet without having to use either an expensive serial terminal server, or an always-online computer with USB hubs and multiple USB-TTL converters. This will also allow users to automate monitoring by using expect, python and other scripting languages. The final goal of making a ready-to-use serial terminal server image for BeagleBone would make it appealing to hardware hackers who can treat this as another tool that works "out of the box".

Quotes from IRC: 2016 Mar 04 17:40:03  I like the serial terminal idea - 2016 Mar 04 17:43:02 * nerdboy would like to see a cape with a set of pins and db9's, each one selectable... - 2016 Mar 04 17:44:45 m_w: my really like that idea too, i might be able to talk her into co-mentor 2016 Mar 04 17:44:51 *my boss even - 2016 Mar 04 17:46:57 use case is up to 5 controller boards 2016 Mar 04 17:47:04 simultaneous - 2017 Mar 16 16:00:53  the trick is making an interface that is more user friendly 2017 Mar 16 16:01:45  just ssh'ing into the target and running minicom is not going to be enough - 2017 Mar 16 16:06:19  perhaps a TUI or web interface to configure the terminals 2017 Mar 16 16:06:55  baud rate, bits, parity, logging file, etc 2017 Mar 16 16:08:09  another nice feature to have would be a hexadecimal viewer 2017 Mar 16 16:09:13  perhaps timestamps would be useful 2017 Mar 16 16:10:12  the trick is packaging the software in a way that you would expect from a consumer product - 2017 Mar 19 17:48:08 m_w: hey I looked through commercial terminal servers and found that some companies also include pattern matching, messaging when certain events occur and tunneling to interconnect 2017 Mar 19 17:48:54  maybe we can add some of those features as stretch goals - 2018 Mar 16 08:34:28  I am partial to CLI interfaces myself, especially if there is tab completion - 2018 Mar 20 15:57:15  serial logging and sessions are gimmies we need a UI of some sort and maybe some integrated scripting support 2018 Mar 20 15:58:28  this project was close to making the cut for the last few years so a good proposal would really up it's chances of being accepted - 2018 Mar 20 16:19:28  illustris, is there going to be an attempt at making some supporting hardware? if so it needs to be ready soon - 2018 Mar 20 16:24:46  scripting and logging are critical features - 2018 Mar 20 16:52:42  serial automation is especially important in embedded test fixtures - 2018 Mar 20 17:42:36  illustris, kermit allows for an expect like interface to poll for expected serial output and conditionally send data out 2018 Mar 20 17:43:11 <m_w_> not saying you have to use kermit but it would be nice to have similar features - 2018 Mar 22 09:15:12 <Wormo> the focus at the end could be to use image builder to generate terminal server images that end users can use, and document how to generate an updated one from latest debian 2018 Mar 22 09:18:50 <Wormo> think about what kind of integration might need to be done to make the image a real turn-key system for users, appeal to some of the hw hackers who could want to treat this as another hw tool that works "out of the box" though customizable if desired