Computer Architecture Lab
This course is a hands-on introduction into computer architecture. The main target is to build a simple, pipelined microprocessor and run it in an FPGA. This course is associated with a real course at the Technical University of Denmark.
Martin Schoeberl
The Challenge
In this course you will design and develop extensions to the T-CREST time-predictable multicore processor and implement it in an FPGA.
The Rules
There are only two rules for your design:
- The design has to be pipelined
- The design has to run in an FPGA
Everything else is up to you. Be creative!
Additional Pages
Grading
The lab work and the project are part of the final grade.
Following points are given for individual parts:
- Instruction Set (RISC-V and comparison): 20 points
- FPGA Design Flow: 10 points
- Project design and implementation: 50 points
- Project documentation (academic research paper style): 20 points
Assignments
Several assignments will help you to get started. We will start on a weekly basis and loosen it up at the end when the main activity is designing your own processor.
As a first action add a template for your project and your name at the Student page.
Instruction Set
- Describe the RISC-V instruction set
- Comparison of RISC-V against other instruction sets
FPGA Design Flow
To get started using an FPGA start with following small projects:
A Simple Blinking LED
The FPGA Hello World Example describes the FPGA design flow with Quartus.
UART Output
A UART will enable you to communicate between a PC and your processor. Therefore, this is our first real VHDL example. For this experiment, connect a serial cable between the FPGA board and the serial port on your PC. Start a terminal program (gtkterm on Linux or Hyperterm on Windows) with baud rate 115200 and no handshake.
Extend the blinking LED example with a UART and write 0 and 1 to the serial line when the LED is off and on.
The Chisel code for the UART transmit is available as part of the Chisel examples at To simplify your design use an additional buffer as shown in the Sender example:
The VHDL code for a UART is available here: sc_uart.vhd and fifo.vhd. The UART is connected via the SimpCon interface.
With the slow output of characters (two per second) you can just write the data to the UART transmit register.
Extend the example by writing repeated numbers 0-9 as fast as the baud rate allows. In this case you have to extend your state machine to poll the UART status to check if the transmit buffer is free.
UART Input (optional)
Implement a state machine that receives characters from the UART. Switch the LED on and off with two different commands received on the serial line.
ModelSim UART print out (optional, not with Chisel)
There is a faster simulation version of the UART available that prints the output to the ModelSim console: sim_sc_uart.vhd.
Having mastered this UART examples gives you a great tool to debug your processor design. The UART output will probably be the only way to communicate with your processor.
For further tips see HOWTO.
Patmos Exercise
Explore Patmos with the provided VM.
Exercise document: Getting Started with Patmos
Argo NoC Exercise
T-CREST Exploration
Get started with the T-CREST/Patmos project. See: http://patmos.compute.dtu.dk/
Documentation
Either in a PDF file or (preferably) within Wikiversity.
Hardware
To implement your design you can use any decent FPGA board. A serial interface (UART) will help for debugging. If you need more memory than the few KB on-chip the board should contain memory chips connected to the FPGA. I suggest using a board with SRAMs as they are easy to connect to the processor.
Students
Add yourself to this list for this semester. It is strongly suggested for the students from DTU.
The former student pages:
References
- CA at Wikipedia
- Microprocessors at opencores.org
- b: Microprocessor Design
- b: VHDL for FPGA Design
- b: Embedded Systems/Particular Microprocessors
TO DO
a short list of open issues:
- nothing open at the moment