help needed with configuration KDF11-A, DLV11-J (PDP 11/23)

From: Pete Turnbull <>
Date: Fri Jan 21 14:16:29 2005

On Jan 21 2005, 12:04, Pierre Gebhardt wrote:

> Currently, I'm trying to set up a 11/23 in a BA23 box with a H9278
> Unfortunately, no information can be found on the jumper
configuration for the KDF11-A (M8186).
> The most important question: Does this CPU-Board provide bus
termination like the KDJ11 boards ?

Yes, it does. There are 4 16-pin DIL terminator packs, usually blue,
usually labeled 1311003-<something>.

> I plugged in some resistor packs on the dedicated sockets of the
H9278 to provide termination, but nothing can be seen on the terminal
(9600, 8N1).

The correct packs?

> I'm aware of the QQ/CD configuration for the first 3 slots.
> The SLU-Card is a SIGMA DLV11-J clone (SDC-DLV11J). Not knowing,
which of the 4 SLUs provides the console interface lead me to check out
the 4 ports on my terminal, unfortunaltey without any success.

Can't tell you anything about that card, sorry.

> The jumper settings on the KDF11-A look like this:
> top
> -----------------------------
> | |
> | |
> | | | These two upper ones are
> | |
> | __ |
> | |
> |
> |
> | __1
> | | | This is a jumper block of 10 jumpers. The
9th one is open.
> | | | The other ones are all closed.
> | | |
> | --- 10
> |
> | |----| |
> ----------- -----------
> backplane
> It's a bit strange, that the jumpers do not have any numbers like W1,
W2 etc.
> That's the reason for this drawing.

Firstly, I can tell you that you have a Revision C board. That's good,
as it supports 22-bit addressing in ODT (Rev.A does 18-bit. Both will
support 22-bit bus addressing under program control if the MMU is
fitted -- it's a 40-pin chip type 21-15542 in the socket nearest the
left of the board as you've drawn it).

Secondly, you've miscounted the jumpers; there are 11 in that block,
not 10. They're jumpers W5 (nearest the card edge fingers) to W15.
 Just to the right of W7 is W4. W3 and W2 are resistors nearest the
right-hand edge of the board; W2 is nearer the fingers and is a real
resistor (usually) and W3 is usually a zero-ohm resistor. The one
you've shown "upright" near the top is W18, and the other one you've
shown, near the right-hand side is W1. The last two are W16 and W17,
just above the fingers at the left.

W1, W2, W3 are things like the clock and must not be removed.
W4 is the BEVENT line; when fitted, it disables BEVENT. It's normally
not fitted, unless you have a programmable clock board.
W5 and W6 select the power-up mode (0,1,2,3).
W7 is the HALT/TRAP option; when fitted, HALT traps to location 000010;
when not fitted, HALT enters ODT. Normally not fitted.
W8 selects bootstrap address for mode 2; when fitted, the processor
jumps to 173000 on power-up; when not fitted, it jumps to an address
selected by W9-W15.
W9-W15 select bootstrap address for power-up mode 2.
W16-17 are reserved and must be fitted.
W18 is the wake-up control and is almost always fitted unless you have
some external circuitry.

Power-up modes:
0: W5 out, W6 out: loads PC from 000024 and status from 00026
1: W5 in, W6 out: enters console ODT
2: W5 out, W6 in: starts bootstrap at 173000 or address from W9-W15
3: W5 in, W6 in: runs extended microcode (custom microcode ROM

If BHALT is asserted when the processor is booted and W5/W6 are set to
mode 2, the processor enters console ODT instead of booting.

W9-W15 correspond to bits 9-15 (the upper byte) of the bootstrap
address for mode 2 if W8 is not fitted. Jumper inserted makes the
corresponding bit a '1'; removed makes a '0'. The lowest byte is
always 000.

You've got W18 fitted, W1 fitted (so the processor should run!) and we
don't know about the rest. However, I'd guess from your description
it's W6 that's fitted in that block, and no others.

Looks like your CPU is several jumpers short of a full set; it would
seem to be set to bootstrap from address 000000.

I'd suggest you use wire-wrap wire and a wrapping tool to jumper some
of the missing ones, or at least move the jumper off W6 and onto W5 (so
it boots into console ODT), and check that W16/W17 are fitted.

Factory default settings are W1, W2/W3, W6, W8-W18 fitted; W4, W5, W7
not fitted. That enables all the clocks and things, and sets the
processor to try to boot from 173000, and to enter ODT on HALT.

> Is the backplane termination required ?

Yes! But you could put a BDV11 or another terminator board in the last
slot, instead. You might get away without it if you only have a couple
of cards in the machine because there are terminators on the CPU.

I've not taken the SIP resistor packs out of any of my H9278s to
measure them, becasue they're a b****r to get at. However, I have some
spare DIL packs from other devices, and I can tell you that each signal
has 180 ohms to +5V and 390 ohms to GND, giving standard 120 ohm
termination. I expect those SIPs have 5V on one end and GND on the

Pete						Peter Turnbull
						Network Manager
						University of York
Received on Fri Jan 21 2005 - 14:16:29 GMT

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