Next week we ship the Bitaxe Naja Duo, and the spec that matters is 9.5 joules per terahash at stock. First open-source home miner under 10. But this is dev.to, so instead of a product pitch, here's the part that's actually interesting to build: what it takes to make a $3 microcontroller drive silicon that Bitmain designed for industrial hashboards and documented for nobody.
The problem: a peripheral with no datasheet
The BM1373 is Bitmain's 3nm SHA-256 ASIC from the Antminer S23 generation. Roughly 2.5 TH/s per chip. No public datasheet, no reference firmware, no SDK. Out of the box it's an inert slab of silicon speaking an undocumented serial protocol.
To make it hash, something has to handle:
Init sequences and chain enumeration: discovering what's on the wire and waking it up
