Why EMBER ONE
Ember One is an open-source hashboard for learning how a multi-chip miner is designed. ASIC communication, power delivery, and thermal design sit on one board. That board connects to a separate controller, such as Libre Board.
The same split is how larger mining systems are built. The hashboard is one board. The controller is another.
EmberOne/00 is the first board. It is a 100 W hashboard with twelve BM1362 ASICs from the Antminer S19j Pro. The v6.1 design uses BM1362AC footprints. Figures for power, size, and the rest are in Specifications.
Power, data, and heat
These are three different problems. The design keeps them separate.
Power. The twelve ASICs are powered in series. That is the electrical arrangement of the core supply. The onboard TPS546D24A feeds that string from a 12–16 V input. The limits are in Specifications.
Data. The series string is not the data path. The chips are linked to each other for command, clock, busy, and reset. The v6.1 schematic names the reset net CHAIN_RST_N. Command, clock, and busy are their own nets, separate from the power rails and from that reset. One UART, TX and RX, leaves the ASIC group. An onboard RP2040 passes that UART over USB to the control board, along with a separate control interface for I2C, GPIO, ADC, and the LED. See USB interface.
Heat. The ASICs and the power MOSFETs both have to be cooled. Ember One does not yet include a heatsink or a water block. For development and testing, you design, adapt, or provide that cooling yourself. The hashboard has no fan connector. See Cooling.
The controller is a separate board
The hashboard does not run the miner. A control board does. Libre Board is one such board. Mining firmware such as Mujina runs there. See Run with Mujina.
The split is what you can work on. Hashboard and controller are developed on their own. A change to one does not require a new design of the other. You can study the chain of chips, the series power, and the cooling on the hashboard while the controller stays a USB host. You can work on the controller while the hashboard stays the board it already is.
Ember One scales up. Libre Board scales down. Ember One is the hashboard, so a larger machine is a larger hashboard: more chips, more power, and the cooling that goes with them. Libre Board is the controller, and it stays the smaller board that drives the hashboard.
Bitaxe
Bitaxe is an all-in-one board. The mining chip and the controller are one design. Bitaxe is earlier work by Skot, the lead maintainer of Ember One. Chip count is not the distinction: a Bitaxe design can use more than one chip.
Ember One is the hashboard alone. It expects a separate controller, which is the arrangement used in larger miners. The pages here are about that hashboard.
What the files are
Ember One and Libre Board are reference designs, not products. The 256 Foundation sells nothing.
We started them. Nobody owns them.