User Experiences of SHAKTI Processor

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In this series of articles, we are collecting the user experiences of SHAKTI. This is from one of our interns in the RISE Lab. It also has a detailed account of all the errors he faced during execution and its solutions.

Development Environment

OSUbuntu on VMware
BoardArty7 35t with Micron Flash

Where did you hear about shakti?

I was doing my internship under Shri Shankar Raman and Shri Anand Kumar. While doing my internship, I got to know about Shakti by them. Then i visited the website for more information.

What were your first thoughts?

As an Indian citizen, I was feeling proud that our India has got a Indigenous processor built from RISE group @ IIT Madras.

Were you able to understand the materials we have?

I didn’t read every material. I understood everything i read, for instance, the Shakti SDK User Manual,Shakti SoC manual.

Were you able to get help from the Forums/video tutorials/ blog articles we have?

Yes, of course. Shakti YouTube channel was helpful for programming the FPGA (Both manually & by MCS).

What are the errors you faced while using shakti?

I got few errors which is listed below. When i couldn’t find the solutions anywhere. I got more ideas from my mentors mentioned above, Learn-With-Shakti, Stack overflow, Shakti YouTube channel,

Error 1:

kapil@Kapil:~$ cd dtc-1.4.7/ 
kapil@Kapil:~/dtc-1.4.7$ sudo make NO_PYTHON=1 PREFIX=/usr/CHK 
version_gen.hLD dtc/usr/bin/ld: multiple definition of `yylloc'; dtc-lexer.lex.o:/home/kapil/dtc-1.4.7/dtc-lexer.l:41: first defined here collect2: error: ld returned 1 exit status make: *** [Makefile:325: dtc] Error 1 


Delete the line 1076 in the file ~/dtc-1.4.7/ Now open the terminal and run the commands. Then the Device tree compiler will be installed successfully.

Error 2:

kapil@Kapil:~/shakti-soc/fpga/boards/artya7-35t/e-class$ make quick_build_xilinx
make[1]: Entering directory '/home/kapil/shakti-soc/fpga/boards/artya7-35t/e-class/boot-code'
make[1]: Entering directory '/home/kapil/shakti-soc/fpga/boards/artya7-35t/e-class/boot-code'
'' Compiling BOOT Polling code ''
'' Caveat: BOOT Code starts at 0x2000. Configure RTL appropriately ''/bin/bash: riscv32-unknown-elf-gcc: command not found
make[1]: *** [Makefile:20: boot.riscv] Error 127
make[1]: Leaving directory '/home/kapil/shakti-soc/fpga/boards/artya7-35t/e-class/boot-code' make: *** [Makefile:150: generate_boot_files] Error 2


User should install the shakti-tools and then execute the command again.

Error 3:

In vivado,

open_hw: Permission Denied. Could not Open Hardware Manager.


Change the Access Permission for /tools as read and write. Then open the terminal and run the vivado command. Now Vivado 2018.3 will run successfully.

Error 4:

HARDWARE MANAGER AUTO CONNECT not detecting arty a7 as in the figure below,

Figure: 1


If you are using ubuntu and vivado in virtualbox, then add an usb extension to the virtualbox for your corresponding version.

Here is the link.

  • Navigate to the “virtualbox6.1.16 oracle vm virtualbox extension pack” and download the extension.
  • Then add it to the virtual box.
  • After that, go to the usb section and select the usb version 2 as in Figure 2.
Figure: 2
  • Now connect the arty a7 board with digilent usb cable and with cable_drivers installed on vivado.

Hurray!! arty is now connected with vivado.

Error 5:

sudo $(which openocd) -f spike.cfg shakti-tools/bin/openocd: error while loading shared libraries: cannot open shared object file: No such file or directory 


If the above error comes execute the following commands,

sudo apt-get -y install libftdi1
sudo apt-get -y install libftdi1-2 

Error 6:

sudo /dev/ttyUSB1 19200sudo: command not found


1. You need to download the pyserial package, If this download fails click here.

2. Follow the below commands,

*Move into the folder into which pyserial is downloaded, then execute the following commands,

tar -zxvf pyserial-2.6.tar.gz
cd pyserial-2.6 
python build
sudo python install

Error 7:

sudo /dev/ttyUSB1pyserial-could not open port '/dev/ttyUSB1': [Errno 2] could not open port /dev/ttyUSB1:[Errno 2] No such file or directory: '/dev/ttyUSB1'


USB1 is not a valid port in this case, Press tab once to automatically get the port to which the board is connected or Press tab twice to see the available options

Error 8:

kapil@Kapil:~/shakti-sdk/bsp/third_party/artix7_100t$ sudo $(which openocd) -f ftdi.cfg
[sudo] password for kapil: 
Open On-Chip Debugger 0.10.0+dev-00615-gfd9c54b (2020-06-04-12:44)
Licensed under GNU GPL v2
For bug reports, read
adapter speed: 1000 kHz
none separate
Info : auto-selecting first available session transport "jtag". To override use 'transport select <transport>'.
Info : Simple Register based Bscan Tunnel Selected
Error: libusb_claim_interface() failed with LIBUSB_ERROR_BUSY
Error: unable to open ftdi device with vid 0403, pid 6010, description '*', serial '*' at bus location '*'


This error occurs when we open multiple OpenOCD’s. Kill all the existing process and start the execution again.

ps aux | grep "openocd"
sudo kill <pid>

What can be improved?

I’m not in such a big position for telling/knowing what to improve. Everything works well. This is a great Success in India and for Indians.

This Post Has 2 Comments

  1. Simmi

    Hello, I’d connected a LED to the board using ground and VCC, but then the board isn’t working, what shall be the fault

Comments are closed.