{"id":1143,"date":"2025-11-20T20:28:06","date_gmt":"2025-11-20T12:28:06","guid":{"rendered":"https:\/\/vm1.go2see.me\/?p=1143"},"modified":"2025-11-20T20:28:06","modified_gmt":"2025-11-20T12:28:06","slug":"embedded-c-programmming-on-risc-v","status":"publish","type":"post","link":"https:\/\/vm1.go2see.me\/?p=1143","title":{"rendered":"Embedded C Programmming on RISC-V"},"content":{"rendered":"

Embedded C Programmming on RISC-V<\/h1>\n

This lab is done INDIVIDUALLY<\/strong>.<\/p>\n

Getting Started with Hardware<\/h2>\n

The following instructions are adapted from Lab 0 for use with C.<\/p>\n

Connect your FPGA board to your laptop and a VGA monitor. There are VGA
\nmonitors in the lab with a BLUE connector on the end. If you do not have a VGA
\nmonitor at home, you can use CPUlator to get started (see below), but to you
\nwill be marked with things running on your FPGA board.<\/p>\n

In Windows, go to Start<\/strong> –> Nios V Command Shell<\/strong> and run the following commands on your laptop:<\/p>\n

make DE10-Lite # VGA will be blank\nmake GDB_SERVER<\/code><\/pre>\n
(alternatively, use make DE1-SoC<\/code>)<\/p>\n
The first command transmits a Nios V computer system to your DE10-Lite board.
\nThe second command will start a program on your laptop that you need to leave running — it
\ncontinuously communicates between your Nios V computer system and your laptop.
\nIf you exit the GDB server by typing Q, the commands below will not longer work.
\nSometimes things get confused and you need to stop everything, including the GDB server,
\nand start over. Sometimes the GDB server can’t find the JTAG server to start — try starting Quartus
\nand then re-run the command.<\/p>\n
Again, go to Start<\/strong> –> Nios V Command Shell<\/strong> and run the following commands on your laptop:<\/p>\n
make TERMINAL<\/code><\/pre>\n
This launches a program to listen and display any characters sent by your Nios V computer over the JTAG UART.
\nLeave this program running to capture everything printed by your program. Control-C will exit.<\/p>\n
You can merge windows by dragging the tab for the Nios V Command Shell window over the tab from the first window.<\/p>\n
Again, go to Start<\/strong> –> Nios V Command Shell<\/strong> and run the following commands on your laptop:<\/p>\n
make COMPILE\nmake RUN<\/code><\/pre>\n
The first command compiles your program, vga.c<\/code> into an object file,
\nvga.c.o<\/code>, and then linking it into an executable, vga.elf<\/code>.  The second
\ncommand transfers the vga.elf<\/code> executable to your Nios V computer and runs it.<\/p>\n
This Nios V program will print the message "start" to the TERMINAL window you started earlier, then it will
\nfill the VGA screen with colour bar pattern, then it will print the message "done".<\/p>\n
You can edit your vga.c program, save it, then run make COMPILE<\/code> and make RUN<\/code> again.
\nHint: the easiest way to edit is with notepad vga.c<\/code>, but you can also right-click the
\nfile and use notepad++ or launch WSL and run vim.<\/p>\n
Using GDB<\/h3>\n
After make COMPILE<\/code>, you can also launch gdb to debug your program:<\/p>\n
make GDB_CLIENT<\/code><\/pre>\n
Note: for some reason, GDB is not working with C code. Use CPUlator instead.<\/p>\n
Using CPUlator<\/h3>\n
Instead of using GDB and using your FPGA board, you can run things on CPUlator.
\nThis tool, written by a former UBC Master’s student \/ UofT PhD student Henry Wong,
\nperfectly emulates the DE1-SoC Computer System with RISC-V as well as several
\nother computers and processors. Henry runs this website on his own.<\/p>\n
http:\/\/cpulator.01xz.net<\/a><\/p>\n
To get started:<\/p>\n