This block diagram illustrates my vision of a Furcula-to-Wishbone bus bridge. The KCP53000 CPU exposes a Furcula bus for both its instruction and data ports. Once these buses are arbitrated to a single interconnect, the KCP53001 is used to talk to Wishbone peripherals and memory.
I tried to get a nice, more or less pretty, static demo for a screenshot on Twitter. But, bugs happened, and I ended up having to debug. Turns out, it made for a better screenshot, because it shows a more realistic user experience. Funny how that works!
When you first "power-on" a Kestrel-3 emulator, it can drop you into the Forth programming language environment. (The Kestrel-3 emulator aims to emulate the Digilent Nexys-2 board, and so has 16MB of RAM.)
Schematic, recalled from memory, of the computing elements of the Kestrel-1 home-made computer. What is NOT shown is the DMA circuitry to load code into RAM under host PC control, and reset logic.
The schematic has one error in it: the BE line is tied high through a 1K resistor, just like the RDY line. This lets the IPL circuitry tri-state the CPU's address and data buses under host PC control.