Yep, but I'm not trying to beef up Bank A on the MoBo at that location.
I'm making adapters to install four double banked 72-pin SIMMs in the slots of Bank B. The first bank of the 32MB, 72 pin SIMM will act as a 16MB 30-pin SIMM in bank B as "usual." The second Bank of each will act as a 16MB 30-pin SIMM in Bank A as in an SE/30.
Since the CPU/MDU can only address Bank B or Bank A on any given cycle, I need to figure out how to multiplex the address and control lines on the adapter using an existing or synthesized Bank Select signal on each of the four adapter. I'm working out how to get around the Vampire Video's Data Line buffering next.
Next to worst case will be implementation of a fifth circuit board multiplexing all the Bank A signals and reflecting them back at the SIMM slots of Bank B.
Worst case would be not being able to get Bank A to work on the adapters in the IIsi, winding up with a way to make inexpensive 16MB SIMMs for Bank B and to max out my Quadra 950 without going broke in the process.
Dunno, but the ersatz Memory line layout/fleshed out Memory schematic I'm building in Illustrator for the project is a pretty neat exercise for learning a bit about Memory Subsystems!
)
I'm making adapters to install four double banked 72-pin SIMMs in the slots of Bank B. The first bank of the 32MB, 72 pin SIMM will act as a 16MB 30-pin SIMM in bank B as "usual." The second Bank of each will act as a 16MB 30-pin SIMM in Bank A as in an SE/30.
Since the CPU/MDU can only address Bank B or Bank A on any given cycle, I need to figure out how to multiplex the address and control lines on the adapter using an existing or synthesized Bank Select signal on each of the four adapter. I'm working out how to get around the Vampire Video's Data Line buffering next.
Next to worst case will be implementation of a fifth circuit board multiplexing all the Bank A signals and reflecting them back at the SIMM slots of Bank B.
Worst case would be not being able to get Bank A to work on the adapters in the IIsi, winding up with a way to make inexpensive 16MB SIMMs for Bank B and to max out my Quadra 950 without going broke in the process.
Dunno, but the ersatz Memory line layout/fleshed out Memory schematic I'm building in Illustrator for the project is a pretty neat exercise for learning a bit about Memory Subsystems!
)