HP82143 Processor details

[blackjetrock]

Does anyone know if there is information about the processor in the HP82143 printer?
I want to add printer output over USB to the Pico attached to an HP41C and I have the NPIC or interface IC so know what the instructions are to get data to and from that IC (the one in the module). What I don't have is any information about how that data maps to the printer. So, for instance, I see the ENPIC instruction in my bus trae and can get data but I have no idea what status is needed to be emulated to get printer data to go from the HP41C to the emulated NPIC or how those characters are formatted.

Andrew