IISI nubus adapter in an SE/30 — #15

Post #15 by trag

Source Forum	68kMLA
Category	Hardware
Post Date	Tue, 10 Apr 2012 - 20:52
Original URL	https://68kmla.org/bb/threads/iisi-nubus-adapter-in-an-se-30.25088/

Post

According to the datasheet, the FPU in 68-pin PLCC has not one, but eight VCC leads :'( And twelve Ground leads.
However, I think a less intrusive way to disable the FPU would be applying VCC to the /CS input (Chip Select, pin 29 -- third from the right of the top row if the index dot is at the bottom).

I don't think that would be a good idea, without confirming where that wire comes from on the adapter board. It might lead all the way back to the /CS pin on the FPU on the logic board, in which case you'd be disabling both FPUs...