SystemVerilog SHA256 Hardware Design / FPGA Bitcoin Miner
The design can now hash as many bytes as is needed for the application. This means it's ready to hash a Bitcoin block, as well (for example).
The module sha_256.sv is a parametrized SHA256 calculator which allows you to hash any data. Usage can be seen in the testbench sha_256_tb.sv.
miner.sv is basically a Bitcoin miner, a module that implements two instances of sha_256.sv and byte-reversing the result. It is specifically made for this task, so you don't have to pass any parameters, just connect the 80-byte block header, a clock and a reset signal, as well as a flag to know whether the hash is calculated and a register to store the hash in.
All testbenches are running fine in Icarus Verilog and the modules return the right results.
As I use this open-source software, that doesn't support System Verilog natively, the modules are always converted to Verilog files with a few simple commands. Because of that I couldn't use exclusive System Verilog features, so it's basically plain Verilog.
Update on the display part: I figured it's easiest to have that part done by an Arduino Nano / 328P, getting the number to display via some pins as there's a great library (Adafruit_SSD1331) that worked perfectly in just a few minutes. My Verilog controller for the PmodOLEDrgb is going to be done some time later on!
Next steps are:
- Getting raw data of the Bitcoin Genesis block (#1)
- Hashing that (#2)
- Executing on FPGA
- Try a combination with a UART USB bridge
- Display hashes via LCD / VGA
- Lots of optimization / making it both more efficient and the code more readable
Useful resources that I used:
(#1):
https://en.bitcoin.it/wiki/Genesis_block#cite_note-block-1
https://webbtc.com/block/000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f.hex
(#2):
https://www.reddit.com/r/Bitcoin/comments/6gl8ol/how_to_manually_verify_a_hash_from_a_block/
The miner_tb.sv tesbench is the easiest way to use / test the main module.
Put a 80 byte BTC block header in the message register and execute the simulation!
Icarus Verilog will also output the computed result to the command line.
As an example, take the first 80 bytes of the block found here and compare them to the hash found when you remove the '.hex' from the link, here.
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