KDJ11-A CPU

KDJ11-A CPU

The KDJ11-A CPU board (M8192) is the first QBUS PDP-11 CPU card using the J-11 chip set. It is a dual-height board, and was used to upgrade PDP-11/23 systems. (Confusingly, no DEC 'PDP-11/xx' system is specified as using the KDJ11-A.)

It contains an 8K-byte write-through cache (set size 1, block size 1 16-bit word), protected by parity; cache control logic inspects DMA transfers on the QBUS and invalidates cache entries for main memory which is written to by a device.

It also provides a set of diagnostic LEDs, and a line time clock; but no other devices (boot PROM, serial line, etc). Both the LTC, and its control register, are enabled by a single configuration jumper (below).

Although the J-11 does implement FP11 floating-point, the board can also use the optional FPJ11 floating point accelerator chip; note that only the -YB version of the board operates correctly with the FPJ11.

Configuration

A limited amount of configuration can be done with a set of nine jumpers (in the middle of the card).Their functions are:

Jumper	Function	In	Out
W1	Bootstrap address bit 15	1	0
W2	Bootstrap address bit 14	1	0
W3	Powerup option bit 2
W4	Bootstrap address bit 13	1	0
W5	Halt enable	Halt	Trap to 4
W6	Bootstrap address bit 12	1	0
W7	Powerup option bit 1
W8	Wakeup circuit	Disabled	Enabled
W9	BEVNT/LTC register	Disabled	Enabled

Powerup options are:

W3	W7	Action
In	In	PC from 024, PS from 026
In	Out	ODT, PS=0
Out	In	PC=0173000, PS=340
Out	Out	PC=configuration jumpers, PS=340

External links

• KDJ11-A CPU Module User's Guide (EK-KDJ1A-UG-002)
• KDJ11-A Field Maintenance Print Set (MP01890-01)