Bitcoin Forum

Hi,

I was working to reverse engineer the chip name: BM1398BB, the same chip used inside Bitminer S19 or S19 pro.

I already figured out the pinmaps and the hardware use of this ASIC. I already made a test pcb with the ASIC. I could reset the chip from the reset pin and also send a 25MHz signal. Even this signal coming out from the CLKO pin. When I am touching the reset pin with GND the current goes back to 1.9 A. But when I am making it high to 1.8V then the current consumption is increasing to 10A.  That proves my experimental hardware is working.

I was sending commands to the PIN: CI and was expecting the response out from: RO
Need to mention that I am using a level shifter IC to convert 1.8V level to 3.3V or vise versa

For sending commands I was following the workformat of BM1385 listed in the datasheet
But looking like the ASIC is not responding with the commands. I think they change their communication protocol for BM1398BB

Now, I was planning to check the software firmware from the Bitminer S19 machine. But I am not sure I will get the source code of the firmware.

Can anyone please help me out establishing communication with BM1398BB ASIC. And what is the protocol to send commands for tasks?

Hey there, sounds cool! I have BM1387 here and a breakout PCB I made, that's waiting for me to have time to tinker with it.
Whatever I found so far about different chips, I gathered here (https://bitcointalk.org/index.php?topic=5357043.0). Maybe there's something in it that will help you. I'm happy to work together once I get to the 'software phase' that you're already in, even though I have slightly different chips.
If you find more documentation on any of the chips, feel free to add links to the above topic!

Regarding firmware; nobody is getting access to the code, however I have not yet tried downloading Bitmain firmware updates and throwing them into a disassembler. I have no idea whether they have symbols or not; if not, they will be a bit more tricky to reverse-engineer.