BeagleBoard/GSoC/2020 Projects/Cape Compatibility

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Revision as of 13:35, 22 March 2020 by Lorforlinux (talk | contribs) (Description)
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Proposal for Cape compatibility layer for BeagleBone Black and BeagleBone AI

Student: Deepak Khatri
Mentors: Jason Kridner
GSoC: [N/A]


This project is currently just a proposal.


Completed all the requirements listed on the ideas page. the code for the cross-compilation task can be found here submitted through the pull request #130.

About you

IRC: lorforlinux
Github: Deepak Khatri
School: Netaji Subhas Univerity of Technology (NSUT) formely NSIT
Country: India
Primary language(s): Hindi,English
Typical work hours: 9AM - 7PM IST
Previous GSoC participation: I participated in GSoC2019 but i was not selected for the project. The project was to make a jekyll website for AIMA organization, Discussion on the project can be found here and the prototype i made can be found here. From the GSoC2019 I learnt the importance of communication.

About your project

Project name: Cape compatibility layer for BeagleBone Black and BeagleBone AI


The idea of this project is to make the same userspace examples work with both BeagleBone Black and AI, using the same references to drivers for peripherals assigned to the same pins between Black and AI. Main things to do for achieving that are assigning similar muxing of pins, same pin names and same aliases for both the boards. Changes will be done in the file am5729-beagleboneai.dts of BeagleBoard-DeviceTrees repo.

  1. For making the boards pin to pin compatible as in pin names, a new node will be created cape-universal {...} which will hold child nodes like P8_03{...} for pin name assignment.
  2. Setting up the same default pin configuration in pin muxing nodes of board device tree files is required which will be achieved using nodes that uses DRA7XX_CORE_IOPAD() functions along with pinctrl-single driver. I have included the required code through pull requests #8 #9 #10. We are also required to assign pinctrl-names by creating nodes like P9_26_pinmux{...} AM335x uses bone-pinmux-helper for doing that.
  3. we also require to assign same aliases which is the easiest part after achieving the above goals. We need some assignments under aliases {...} node similar to what we have in BeagleBone Black device tree file.

After testing we may require to create new device tree sources include (dtsi) files. The file am335x-bone-common-univ.dtsi for BeagleBone Black and am335x-pocketbeagle.dts provides all the information for pinmuxing and pin naming. The porject will enable us to use serial ports and userspace I2Cdev/spidev, aliases provided by the device trees would match. For GPIOs, examples would work using pin names under libgpiod.

The project requires the use of the device tree compiler (dtc) for compiling the device tree source (ex. *.dts, *.dtsi) files. The c programming language will be used for kernel-level programming and gcc compiler along with other build tools will be used for compiling the C source code (*.c).


Apr 27 Pre-work Community Bonding Period and discussion on the project and resources available.
May 18 Pre-work complete Coding officially begins!
May 25 Milestone #1
  • Introductory YouTube video.
  • Setting up BeagleBone Black and Ai boards.
  • Running cape examples and user space examples on BeagleBone Black.
June 1 Milestone #2
  • Analysing the full process of naming GPIO, P8 and P9 header pins on Black.
  • Getting more information on how to create a device tree source and include file.
  • Learning the process of creating device tree overlays and running some examples on the Black
June 8 Milestone #3
  • Reading and understanding the System Reference Manual for Beagle bone Ai.
  • Start working on the "Linux/arch/arm/boot/dts/am335x-bone-common-univ.dtsi" and related device tree files.
  • Detailed discussion on the work done till now.
June 15 - 19 18:00 UTC Milestone #4
(Phase 1 Evaluation)
  • Demonstrating the work through examples.
  • Documenting everything and submitting the report for evaluation.
June 22 Milestone #5
  • Taking notes and feedback from my mentor on the quality of code.
  • Testing the pin control using libgpiod.
  • Writing new examples & running available examples that demonstrate the proper working of pin control using libgpiod.
June 29 Milestone #6
  • Start learning about how to create device tree aliases.
  • Writing aliases for the Ai board pins with compatibility with Black.
  • Writing examples for the work in progress.
July 6 Milestone #7
  • Running userspace examples provided for Black on Ai.
  • Testing example code for at least 1 cape on Ai.
  • Detailed discussion on the work done till now.
July 13 -17 18:00 UTC Milestone #8
(Phase 2 Evaluation)
  • Demonstrating the cape compatibility.
  • Documenting everything and submitting the report for evaluation.
July 20 Milestone #9
  • Testing more capes on Beagle Bone Ai.
  • Code cleaning and proper commenting if not done already.
  • Taking notes and feedback from my mentor on the quality of code.
July 27 Milestone #10
  • Documenting everything done during the summer.
  • Taking feedback from my mentor.
August 3 Milestone #11
  • Completion YouTube video
August 10 - 17 18:00 UTC Final week Students submit their final work product and their final mentor evaluation
August 17 - 24 18:00 UTC End of competition Mentors submit final student evaluations

Experience and approach

I have a good understanding of C, C++, and python. I have done an internship on Embedded Electronics using BeagleBoneBlack. I completed this project called "Mausam national" during my internship. Mausam national is an air quality cum multiple gases ppm level acquisition system. The interesting part of the project is that it can connect to the internet and fetch the air quality data from my university's pollution center that they provide for everyone to use. we used that data for the calibration of the MQ sensors on-board.

I was one of the quarter-finalists in IICDC2017 and during that period I worked with ARM cortex M4 based MSP432. I participated in Electronics Maker contest '17 there I presented a low-cost biopotential amplifier based on TL074 and won Ti's C2000 DSP for the project. I have worked on both hardware and software-based projects, hardware projects can be found on my youtube channel here and software projects can be found on my GitHub here.


I believe that if I get stuck on my project and my mentor isn’t around, I will use the resources that are available to me. Some of those information portals are listed below.

  1. Derek Molly's beagle bone guide provides all the information needed for getting up and running with my beagle.
  2. Content on is very useful for information that ranges from tutorials and walkthroughs to the level of very advanced stuff.
  3. BeagleBone cookbook from Mark A. Yoder & Jason Kridner is the best source for test projects during the prototyping period.
  4. The technical reference manuals provided by TI on am3358 and am5729 are the best source for getting the insights on the SoC used in Black and Ai.


If successfully completed, what will its impact be on the community? Include quotes from community members who can be found on and


Is there anything else we should have asked you?