> On Feb 8, 2016, at 1:08 PM, Ian S. King <[email protected]> wrote: > >> >> See above re: gold edge fingers. I was originally thinking that if I do >> have to >> split the board up, that I’d make them completely independent. But that >> has >> the issue of requiring 2x the number of UNIBUS transceiver parts (which are >> all but unobtainium as of now). One of the things that drives up the >> power (and >> board area) are said transceivers (and level shifters, etc). If I could >> come up >> with a reasonable alternative for the SPC version, that may work. But >> that’s >> all in the future at the moment. >> >> TTFN - Guy >> >> > A thought: would a second quad board necessarily need transceivers? I'm > thinking of the top-block connectors used in the PDP-8, and the top-plugged > ribbon cables for e.g., MicroVAX II CPU-to-memory connection. You might > still want to grab power through a few fingers, but that's an > implementation detail. — Ian >
I’m not a particular fan of that because some of the signals I’m running are pretty fast between the FPGA and some of the other components (~40ns cycle time for the FRAMs for example). I wouldn’t want to run those signals very far and certainly not across any sort of cabling. It’s not clear to me (yet) how I could partition the design across 2 SPC boards. TTFN - Guy
