Unobtainium obtained!

On Tue, Dec 11, 2012 at 02:55:38PM -0500, David Riley wrote: Not as a pin-compatible part for repair of existing boards, no. If that's what you're going for, that's a great idea! An 8646A clone circuit on a tiny daughterboard might be cool too (for the KS10/VAX crowd). But I've got first-cut PCBs stuffed (and awaiting firmware) for a couple of projects which need to talk to DEC busses but don't need the DS8641N pinout: - Unibus battery-backed RAM and clock/cal board, (for my own use -- I know it's trivial but my main 11/34a's MS11Ls have gotten super flaky and I always wanted a TOY clock). This is a dual-height board, 3" tall, which fits in A/B of a MUD slot. Embarrassingly, it has a CPU, just to save square inches, but now that it's there, doing a KDJ11E-compatible TOY clock becomes easy, and doing config through an RS232 port is easy too so there are no jumpers. - Unibus universal disk controller (will be a D Bit product if successful). First prototype is a 6"x6" board with ribbon cables for a PCI/Unibus adapter (without the M9014-like Unibus paddle card) and an M9302-like terminator daughterboard with female Bergs on the back, so I can debug the firmware using E11 w/o hauling a big noisy BA11K into my little office. If I get this working, the next rev will be a quad SPC. SATA/USB/SD, with an 18-bit data path (obviously!). Anyway for these I'm seeing if I can get away with receiving the bus using 74LVC240s (etc.) and transmitting using a gazillion 2N7002PWs with 100 ohms in series with the gate (hoping that plus the gate capacitance will get the slew rate into a good neighborhood). Technically none of this is OK but I'm hoping in practice it works. Once the firmware's taking shape, a scope will tell all... Yours sounds better than mine, so, nope! Probably just as well to do it with loose parts though -- you don't want to get dependent on *another* oddball chip that'll be rare five years from now. John Wilson D Bit