ASIC CHIP COMMANDS WORK FORMAT S19

[amilkarnunez]

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?

[1714542321]

1714542321

[n0nce]

~

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. 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.