The "Bus Pirate V4" is connected to the PCF8570 via the signal lines MOSI and CLK.
These "clips" of the logic analyzer can be used for this purpose.
I can not provide any information about the commands at the moment, as my "Bus Pirate" is still on the way from China to me in Switzerland.
As soon as the device arrives, I will send you the necessary commands.
But now to another question.
Do you know why the command to set the serial number in AM5030 = "SERIAL [space] [space] B12345" does not work?
That with the calibration data "CALC 00,25000" works.
That's why I started to measure the data stream with the logic analyzer in order to change this serial number.