RC11 controller (Was: Reproduction DEC 144-lamp indicator panels)

On 12/9/21 8:15 PM, Jay Jaeger via cctalk wrote: Why does everyone seem to want to emulate HW like this with a micro when a reasonable FPGA implementation with some external FRAM would do the job? The SMD/ESDI emulator that I've been working on has to "brute force" the emulation because of BW concerns.? That is, it has to read the entire emulated disk image into DRAM because: 1. You need at least a track's worth of buffering to send/receive the data though the data interface (serial) 2. You don't have enough time to transfer tracks in/out of the track buffer to flash (or what ever) to meet the head switch times 3. You don't have enough time to transfer whole cylinders in/out of the cylinder buffer to flash (or what ever) to have reasonable track-to-track seek times So it will require a micro, but that's mainly to manage what's going in/out of the (large) DRAM back to flash (it reads the entire emulated disk image into DRAM during boot).? All of the actual commands and data movement across the interface are all done by an FPGA. -- TTFN - Guy