[HECnet] pdp-11/83-84

On 07/05/2012 09:00 PM, Paul_Koning at Dell.com wrote: On Jul 5, 2012, at 7:35 PM, Johnny Billquist wrote: ... Oh, and I saw some additional discussions about the CIS option for the F11. Unless I remember wrong, and understood things wrong, it is not just a simple PROM. It's a coprocessor, which have logic in addition to whatever microcode the coprocessor need. So no way of just duplicating a PROM to get a CIS. Not unless someone could dig up the details. If it *is* just a PROM, even if it's an oddball bipolar model with different interface specs, it should be easy to reproduce that with a small FPGA. Any reasonable modern FPGA is way faster than a 1980s era bipolar ROM, so modeling the interface timing should be easy. And level conversions should be doable. So a sort of daughterboard? That's a good idea. I'm pretty sure the F11's manuals are out there, but I haven't gone digging for them. From that, and possibly even just from the KDF11-Bx schematics, one should be able to glean the important parts of how to interface to the microinstruction and microaddress buses. Then all we'd need is a copy of the actual code. -Dave -- Dave McGuire, AK4HZ New Kensington, PA