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KD11-F CPU and H9278-A backplane

J

jmdhuse

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Hello All -

Can I use this backplane with the LSI-11/03 if I just avoid using the first three slots that are mixed QQ and CD? I was thinking that I could put the CPU in slot 4, then continue with RAM, SLU, and then boot ROM modules.

Thanks, Jon.
 
You wouldn't want to install a KD11-F M7264 in a Q22/Q22 slot if any other modules installed in the backplane use BDAL18-21 for 22-bit addressing. The KD11-F M7264 uses DC1, DD1, DE1, DF1 for purposes other than BDAL18-21.

A KD11-F M7264 might be OK in Slot 1 of a H9278-A, if jumper W3 connecting DK1 and DL1 together is removed. DC1, DD1, DE1, DF1 aren't connected to anything else in Slot 1.

Probably need to take a closer look at this schematic to see if there are any other issues:
http://www.bitsavers.org/pdf/dec/pdp11/1103/1103_Schematics.pdf

LSI-11 CPU Module (K8) SHEET 8 of 9
KD11-F_M7264_Dx1.png
LSI-11 CPU Module (K9) SHEET 9 of 9
KDll-F_M7264_DKL1.png
 
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gslick said:
A KD11-F M7264 might be OK in Slot 1 of a H9278-A, if jumper W3 connecting DK1 and DL1 together is removed. DC1, DD1, DE1, DF1 aren't connected to anything else in Slot 1.
Click to expand...

After taking a further look, if I understand things correctly, a KD11-F M7264 would normally originally be installed in an H9270 backplane, and in an H9270 backplane in every slot BK1 is only connected to BL1 of the same slot, and DK1 is only connected to DL1 of the same slot. So the KD11-F M7264 expects BK1 to be connected to BL1, and that DK1 is connected to DL1.

In an H9278 backplane in every slot BK1 is only connected to BL1 of the same slot. Where I mentioned jumper W3 above in the previous reply, that was looking at the H9276 backplane, not the H9278 backplane. There is no W3 equivalent jumper in the H9278 backplane, and DK1 is probably not connected to DL1 in slot 1, I'm not currently sure about that. So if the KD11-F M7264 does require DK1 to be connected to DL1, it probably won't work in the first 3 Q22/CD slots of an H9278 backplane. Then in the remaining 5 Q22/Q22 slots of an H9278 backplane there is the issue of the the KD11-F M7264 using DC1, DD1, DE1, DF1 for purposes other than BDAL18-21.
 
gslick said:
You wouldn't want to install a KD11-F M7264 in a Q22/Q22 slot if any other modules installed in the backplane use BDAL18-21 for 22-bit addressing. The KD11-F M7264 uses DC1, DD1, DE1, DF1 for purposes other than BDAL18-21.
Click to expand...
"Restricted Compatibility Options" list in the second half of Micronote #5 Q22 Compatible Options:

Also useful information in http://www.vaxhaven.com/images/8/8d/EK-LSIFS-SV-005-vol1.pdf but not a direct answer!
 
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Yeah, it's beginning to look like the solution is either find an H9275-A or an H9276 backplane, or design one of my own...
 
Attached is the schematic for the H9276; see note on upper-right of page 9-of-11. The LSIFS description of the H9275 makes clear that the W6/7/8/9 jumpers simply add/remove the CPU connections to the four BDAL address lines. There's nothing wrong with driving those lines per se; just stick to 18-bit addressable modules (micronote #5) -- which you'll need to do anyway with the KD11-F. If you are very concerned, then cut those four traces on the KD11-F itself (unless you can do that on the backplane -- I haven't checked, but I doubt it). AFAICS you can use Slot 3 for the KD11-F since it's wired directly to Slot 4 as part of the "serpentine" configuration; just keep Slots 1-2 empty (and thus ignore any signalling on CD).

What is your exact intended module set?
 

Attachments

  • H9276-B (BA11-S_schem_Mar81).pdf
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Of course, caveat emptor. https://gunkies.org/wiki/QBUS is also a good read. "electrically incompatible" as used there near the bottom of the page is unfortunately ambiguous -- could mean something like pin reassignment that shorts +5Vdc to GND, or simply _electronically_ incompatible e.g. the BDAL situation. I'd go with the LSIFS statements rather then the overly broad warning in gunkies. However gslick may be on to something ...
 
Initially, I plan to have the CPU, M8044 32KW memory, and probably a DLV11-J. That will enable me to boot XXDP from a TU58 emulator and start running diagnostics. It's possible that I might add a RQDX3 disk controller, but I suspect that would tamper with the 4 upper address lines that are being used for something else (it appears that they are used to indicate some kind of CPU action status).
 
jmdhuse said:
It's possible that I might add a RQDX3 disk controller
Click to expand...
This (M7555) requires a Q22 backplane, which then means that you want a 22-bit memory CPU which means at least a F11 with MMU which means at least an 11/23 (KDF11-A, dual-height) or 11/23+ (KDF11-B, quad-height). Refs:

KDF11-A CPU - Computer History Wiki

gunkies.org gunkies.org

KDF11-B CPU - Computer History Wiki

gunkies.org gunkies.org

There are several KDF11-A on eBay at the moment, although IMO very overpriced. Consider making a cost-effective offer on https://www.ebay.com/itm/185376423188 as the vendor has a pile of them to "move" rather than chasing the H9273 backplane, unless you intend to stick with some of the limitations of the LSI11-era. You should be able to acquire a KDF11-A at same-or-cheaper cost than yet another backplane. The current offered prices for KDF11-A are much too high. One sold at end-January for $52.00 +$10.95 shipping. YMMV, of course.
 

Attachments

  • EK-RQDX3_RQDX3_Controller_Module_Users_Guide_Nov85.pdf
    1.6 MB · Views: 3
Steve Toner said:
Yeah, but suppose I had a spare H9273 backplane (which I do) that I'd be open to trading with OP Jon? :)
Click to expand...
What would you take in trade? I have a spare KDF11-A and a spare KDF11-B CPU board. And I have a board I designed and build that can act as either a BDV11 or MVX11-B2 for boot ROMs (it is not a multifunction module, just a boot ROM module).
 
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