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skot / bitaxe

Open source ASIC Bitcoin miner hardware
GNU General Public License v3.0
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Mode Pins on BM1366 #89

Closed shufps closed 11 months ago

shufps commented 11 months ago

Hi,

I'm a bit confused about how the caps C4 and C16 are connected to the BM1366.

image

What purpose do the mode_0, mode_1 and modeo pins have?

And what I also wondered - where did you find this awesome information?

I searched a lot and didn't find any schematics to the BM1366 - not even in the repair guides of Bitmain.

Thx, Thomas

skot commented 11 months ago

The mode pins change the direction of the data pins. Ie mode1 is inputs on the left and outputs on the right. Mode0 is the opposite.

Those mode names are arbitrary of course because we don't have any schematics or pinouts.

shufps commented 11 months ago

Thank you, this is almost what I thought for what they are :sweat_smile:

What I still don't understand is that mode_1 and modeo have caps to 0.8V.

So I suspected there must be more going on - like extra caps for a charge-pump that uses the pins that are labeld with modeo and mode_1 or so idk.

If it's not a charge pump then I absolutely have no idea what purpose the caps have :sweat_smile:

shufps commented 11 months ago

I revised the schematic on my branch and added back the 1µ caps. Probably it was stupid to remove them in the first place :grimacing: You seem to have real hardware for reverse engineering - I ofc don't :see_no_evil:

Ordered my HAT and parts ... let's see how it's going :crossed_fingers:

skot commented 11 months ago

Now you have me wondering about this too. What we have is definitely working on the single-ASIC bitaxe. I'm going to look a little deeper into this for the multi-ASIC bitaxeHex.

I don't think it's a charge pump. From what I can tell it's just trying to passthrough the mode from one chip to the next in the chain.