Hello.how can we use arduino as bitcoin miner control board to control hash boards?cause i think the protocol of hash board is uart.and also we can connect more than 3 hash board to a cheap control board.
I suggest to use pushbuttons and wires.
I'd connect the hash boards to each other by their multiple serial channels, and connect the Arduino by I2C.
BTW, what's a hash board? WRT to bitcoin mining I'd second the buttons&wires approach 