We are going to start our breadboard RISC-V project. We build a simple RISC-V with students to fulfill the below requirements. The breadboard CPU is simple, but we will be in full stack, code the testing program in GCC, debug via GDB with our own jtag and by openocd.


  1. A controllable program counter. We can set its speed and pause it at any time manually
  2. Support some basic instructions such as below
  3. Provide LED to indicate the status and register values on board
  4. Data bus & instruction bus
  5. 3 Stage pipeline and visualize it
  6. We use STM32 to build the USB tag and plug to our breadboard RISC-V, write openocd driver and able to dump out registers and single step via GDB

Remark 1:

Outside the RISC-V we still need some components such as a programmable clock generator, we do all that by ATtiny85 and flash it via this device

Remark 2:

For the memory rather than using gates, we use dip memory such as 24AA32AF and this device and flash the EEPROM memory

Bill Of Material

Digital Design and Computer Architecture: RISC-V Edition4$350
We need some OLED (don’t know how many, just buy them all)
0.96 inch x 20 + 1.3 inch x 20
8-segments LED100$300
USB Power Supply3$60
Button x 50 for each student3$80
Cable x 300 for each student3$50
We need some gates but I don’t know which one, so buy them all3$800
STM32 board and JTag to offload some logic outside RISC-V3$100
Logic Analyzer3$80
Ben Eater Complete 8-bit breadboard computer kit bundle3$7020
Total =$10880