Hello My name is Peyton and after coming across your project on github it inspired me to work on my own product which I didnt realize until today that it was discussed on the forum page about the bitaxe 1387 version. but anyway my project is a 12 asic BM1397 hashboard that is the same formfactor as a matx motherboard so you can put it in a slim matx case. my plan is to power it with an apw 3. I will link some 3d renders of it. But the plan is to cool it with standard LGA1151 heatsinks and its 4 asics per heatsinks and 3 heatsinks. My idea which im not sure if it will work is to basically have 6 domains where there are 6 sets of two chips in series. the power will come from 12 volt of the apw3 and get stepped down to 5v then 3.3v which then powers the 2 asic domain splitting the power into 2 coming to that 1.6 vdd line it needs. It also will be controlled by a rpi cm4. That will run the linux which runs kano theoretically. What I think I need your help on is the actual communication portion. my plan is to make a built in ttl connector which is hardwired into the cm4 as a usb port with a dip switch to power it off if necessary. I think I can figure out how to wire that ttl connector up no problem, what I dont know how to do is connect the asics to said "ttl adapter" or how to actually make the chips do any work. any guidance you can give me of how to connect and communicate with the asics would be much appreciated and lmk what you think!
https://gyazo.com/24625a4510e0393d42d2ae27f94f5ebc - overall
https://gyazo.com/438c1e7d3284387ee43fe1a1162a8a45 - overall back
https://gyazo.com/ae867ddc0d43c6b0dc4fe1b36e88fbf1 - asic layout, 8 pin ic 5v 5 pin 3.3v, not fully put together but should work in theory?
https://gyazo.com/91955ccfa9e6b9f295086913b4efdbb6 - serial ttl adapter, 12v power, cm4, gpio pin set, startings of power circuitry to power the cm4
I am designing it through easy eda as thats the software I like best and could send you the files if youd like. again any help would be appreciated!
Dude, that's rad! fitting it in the micro atx case is a great idea. I wonder if you could make it work with normal PC power supplies that also fit in the matx case? Don't they have some beefy 3.3V rails?
A couple things you might watch out for;
- BM1397 core voltage is nominally 1.5V. The 1.65V you have would probably work but be inefficient unless you're running a high hash frequency.
- Careful of the BM1397 copper tops, they are connected to GND, which won't be at the same potential if you have the chips in series. ie, a common heatsink between two BM1397's in series is going to short them.
- What voltage regulators are you using for 5V and 3.3V? They need to handle a lot of current, and/or have a lot of them.
You should be able to get a design for a FTDI or similar usbserial chip connected to the CM4. I think the official RPi CM4 IO board has one.
https://www.raspberrypi.com/products/compute-module-4-io-board/ (They have the design files available for KiCad
)
As far as the connections between BM1397's I bet @developeralgo could help you here. I haven't looked into this yet. There is also the S17 Repair guide
Once you've got linux running and the BM1397's attached to a usbserial chip, you can just look at cgminer kano edition for how to communicate with them.
https://github.com/kanoi/cgminer The recent changes for the Gekkoscience Terminus R909 should get you pretty close. That miner has 6 BM1397's
https://bitcointalk.org/index.php?topic=5423227.0Maybe put your design files up on GitHub and post the link here?
Also, You should really check out KiCad! It's free, open source, cross platform and great for sharing files on the internet. It's a bit quirky to learn at first, but if you can get past that you'll love it. No advertisements either
You would think someone who works for Bitdeer repairing miners all day would remember that the 1397s tops are connected to ground. Silly me. I’ll have to think of something other than thermal pads because the goal is to be super quiet. (APW3 doesn’t qualify as super quiet i know, the 3.3 rail Isn’t a bad idea. I’ve used kicad before just more familiar with easyeda. What should the current be for two chips? The one i have is a 3.3v 1amp
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