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List of PDP-8 Omnibus signals

intabits

Experienced Member
Joined
Jan 22, 2019
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148
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I wanted, but could not find a cleanly formatted list of the PDP-8 Omnibus signals.
So I've created the list below from Appendix B of the "PDP-8/e/f/m MAINTENANCE MANUAL VOLUME 1"

Please let me know if:
- Such a list already exists
- This list is of any use at all
- There is a mistake in my list
- (almost certainly) References to M830, M835 & M836 should be M8300, M8350 & M8360?
- You know of any (other) errors in the appendix data
- Any other information should be incorporated in this list (and where to get it)
eg: Type/Class of signal (power, bus, ctrl, misc, etc)
- Other formats for this list are of any value? (eg: CSV)


Notes:
- I'm not very familiar with the signal names, some of the those found in the appendix may not be the definitive ones
eg: those given for C1L, C1V seem weird
- This list is created by some manual editing of a source list, which is read by a program to produce the output below.
So simple formatting changes are easy to make.
- OCR errors are possible, but I think I've caught them all


Some changes were made to the values found in the appendix:-
- '-' replaces spaces in signal names
- P.S. replaced with PSU


Code:
Pin  Signal               Source                          Destination
A1A  TP                                                   Not bussed
A1B  TP                                                   Not bussed
A1C  SPGND                PSU                             ALL
A1D  MA0-L                M8360,M8300                     KC8-EA,M8330,M8300,G227
A1E  MA1-L                M8360,M8300                     KC8-EA,M8330,M8300,G227
A1F  GND                  PSU                             ALL
A1H  MA2-L                M8360,M8300                     KC8-EA,M8330,M8300,G227
A1J  MA3-L                M8360,M8300                     KC8-EA,M8330,M8300,G227
A1K  MD0-L                M8300,G104                      KC8-EA,M8330,M8310,M8300,G104,M8350
A1L  MD1-L                M8300,G104                      KC8-EA,M8330,M8310,M8300,G104,M8350
A1M  MD2-L                M8300,G104                      KC8-EA,M8330,M8310,M8300,G104,M8350
A1N  GND                  PSU                             ALL
A1P  MD3-L                G104,M8300                      KC8-EA,M8330,M8310,M8300,G104,M8650,M835
A1R  DATAO-L              KC8-EA,M8350,M8300,M8360        KC8-EA,M8330,M8300,M8350,M8360
A1S  DATA1-L              KC8-EA,M8350,M8300,M8360        KC8-EA,M8300,M8350,M8360
A1T  GND                  PSU                             ALL
A1U  DATA2-L              KC8-EA,M8350,M8300,M8360        KC8-EA,M8330,M8300,M8350,M8360
A1V  DATA3-L              KC8-EA,M8350,M8300,M8360        KC8-EA,M8300,M8350,M8360
A2A  +5                   PSU                             ALL
A2B  -15                  PSU                             ALL
A2C  GND                  PSU                             ALL
A2D  EMAO-L               M8360                           KC8-EA,G104
A2E  EMA1-L               M8360                           KC8-EA,G104
A2F  GND                  PSU                             ALL
A2H  EMA2-L               M8360                           KC8-EA,G104
A2J  MEM-START-L          KC8-EA                          M8330
A2K  MD-DIR-L             M8330,KC8-EA,M8360              KC8-EA,M8300,G104
A2L  SOURCE               M8330                           G227
A2M  STROBE               M8330                           G104
A2N  GND                  PSU                             ALL
A2P  INHIBIT              M8330                           G104
A2R  RETURN               M8330                           G104,G227
A2S  WRITE-L              M8330                           G104,G227
A2T  GND                  PSU                             ALL
A2U  ROM-ADDR-L           M880                            M8310,G104,M880
A2V  LINK-L               M8310                           M8330
B1A  TP                                                   Not bussed
B1B  TP                                                   Not bussed
B1C  GND                  PSU                             ALL
B1D  MA4-L                M8360,M8300                     KC8-EA,M8330,M8300,G227
B1E  MA5-L                M8360,M8300                     KC8-EA,M8330,M8300,G227
B1F  GND                  PSU                             ALL
B1H  MA6-L                M8360                           KC8-EA,M8330,M8300,G227,M8300
B1J  MA7L                 M8360                           KC8-EA,M8330,M8300,G227,M8300
B1K  MD4-L                G104,M8300                      KC8-EA,M8330,M8310,M830,G104,M8650,M8350
B1L  MD5-L                G104,M8300                      KC8-EA,M8330,M8310,M830,G104,M8650,M8350
B1M  MD6-L                G104,M8300                      KC8-EA,M8330,M8310,M8300,G104,M8650,M8350
B1N  GND                  PSU                             ALL
B1P  MD7-L                G104,M8300                      KC8-EA,M8330,M8310,M8300,G104,M8650,M8350
B1R  DATA4-L              M8360,KC8-EA,M8650,M8300,M8350  KC8-EA,M8300,M8650,M8350
B1S  DATA5-L              M8360,KC8-EA,M8650,M8300,M8350  KC8-EA,M8300,M8650,M8350
B1T  GND                  PSU                             ALL
B1U  DATA6-L              M8360,KC8-EA,M8650,M8300,M8350  KC8-EA,M8300,M8650,M8350
B1V  DATA7-L              M8360,KC8-EA,M8650,M8300,M8350  KC8-EA,M8300,M8650,M8350
B2A  +5                   PSU                             ALL
B2B  -15                  PSU                             ALL
B2C  GND                  PSU                             ALL
B2D  INTSTROBE            M8330                           M8330,M8360
B2E  BRK-IN-PROG-L        M8360                           KC8-EA
B2F  GND                  PSU                             ALL
B2H  MA-MS-LOAD-CONT-L    M8360                           M8310
B2J  OVERFLOW-L           M8310                           M8360
B2K  BRK-DATA-CONT-L      M8360,KC8-EA                    KC8-EA,M8310
B2L  BREAK-CYCLE-L        M8360                           KC8-EA
B2M  LD-ADD-ENABLE-L      KC8-EA                          KC8-EA,M8310
B2N  GND                  PSU                             ALL
B2P  INT-IN-PROG-H        M8330                           M8310,M8330
B2R  RES1                                                 Reserved for DEC use on1y
B2S  RES2                                                 Reserved for DEC use on1y
B2T  GND                  PSU                             ALL
B2U  RUN-L                M8330                           KCS-EA,M8330,M8350
B2V  POWER-OK             PSU                             M8330,G104
C1A  TP                                                   Not bussed
C1B  TP                                                   Not bussed
C1C  GND                  PSU                             ALL
C1D  I/O-PAUSE-L          M8330                           M8330,M8310,M8650,M8350
C1E  CO-L                 M8650,M8350,M8330               M8310
C1F  GND                  PSU                             ALL
C1H  C1-L                 M8650,M8350,M8330               M8310
C1J  C2-L                 M8350                           M8310
C1K  BUS-STROBE           M8330,M8350                     M8310,M8330
C1L  INTER.-I/O-L         M8330                           M8650,M8350
C1M  NOT-LAST-TRANSFER-L  M8350                           M8330
C1N  GND                  PSU                             ALL
C1P  INT-RQST-L           M8650                           M8330,M8350
C1R  INITIALIZE           KC8-EA,M8330                    KC8-EA,M8330,M8310,M8300,M8650,M8350,M836
C1S  SKIP-L               M8650                           M8330,M8310
C1T  GND                  PSU                             ALL
C1U  CPMA-DISABLE-L       M836                            M8300
C1V  MS-IR-DISABLE-L      KC8-EA                          M8330,M8310,M8360
C2A  +5                   PSU                             ALL
C2B  -15                  PSU                             ALL
C2C  GND                  PSU                             ALL
C2D  TP1-L                M8330                           M8310,M8330,M8350,M8360
C2E  TP2-L                M8330                           M8310,M8330,M8350,M8360
C2F  GND                  PSU                             ALL
C2H  TP3                  M8330                           M8310,M8330,M8650,M8350
C2J  TP4                  M8330                           KC8-EA,M8310,M836
C2K  TS1-L                M8330                           KC8-EA,M8330,M8310,M8350,M8360
C2L  TS2-L                M8330                           M8310,M8360
C2M  TS3-L                M8330                           KC8-EA,M8310,M8350
C2N  GND                  PSU                             ALL
C2P  TS4-L                M8330                           KC8-EA,M8310,M8360
C2R  LINK-DATA-L          M8330                           M8310
C2S  LINK-LOAD-L          M8330                           M8310
C2T  GND                  PSU                             ALL
C2U  IND1-L               KC8-EA                          M8330,M8310
C2V  IND2-L               KC8-EA                          M8330,M8310
D1A  TP                                                   Not bussed
D1B  TP                                                   Not bussed
D1C  GND                  PSU                             ALL
D1D  MA8-L                M8360,M8300                     KC8-EA,M8330,M8300,G227
D1E  MA9-L                M8360,M8300                     KC8-EA,M8300,G227
D1F  GND                  PSU                             ALL
D1H  MA1O-L               M8360,M8300                     KC8-EA,M8300,G227
D1J  MA11-L               M8360,M8300                     KC8-EA,M8300,G227
D1K  MD8-L                G104,M8300                      KC8-EA,M8330,M8310,M8300,G104,M8650,M8350
D1L  MD9-L                G104,M8300                      KC8-EA,M8330,M8310,M8300,G104,M8650,M8350
D1M  MD10-L               G104,M8300                      KC8-EA,M8330,M8310,M8300,G104,M8650,M8350
D1N  GND                  PSU                             ALL
D1P  MD11-L               G104,M8300                      KC8-EA,M8330,M8310,M8300,G104,M8650,M8350
D1R  DATA8-L              M8360,KC8-EA,M8650,M8300,M8350  KC8-EA,M8300,M8650,M8350
D1S  DATA9-L              M8360,KC8-EA,M8650,M8300,M8350  KC8-EA,M8300,M8650,M8350
D1T  GND                  PSU                             ALL
D1U  DATA10-L             M8360,KC8-EA,M8650,M8300,M8350  KC8-EA,M8300,M8650,M8350
D1V  DATA1-1-L            M8360,KC8-EA,M8650,M8300,M8350  KC8-EA,M8300,M8650,M8350
D2A  +15                  PSU                             ALL
D2B  -15                  PSU                             ALL
D2C  GND                  PSU                             ALL
D2D  IRO-L                M8310                           KC8-EA,M8330,M8310
D2E  IR1-L                M8310                           KC8-EA,M8330,M8310
D2F  GND                  PSU                             ALL
D2H  IR2-L                M8310                           KC8-EA,M8330,M8310
D2J  F-L                  M8310                           KC8-EA,M8330,M8310
D2K  D-L                  M8310                           KC8-EA,M8330,M8310
D2L  E-L                  M8310                           KC8-EA,M8330,M8310
D2M  USER-MODE            USER                            KC8-EA,M8330
D2N  GND                  PSU                             ALL
D2P  F-SET-L              M8310                           KC8-EA,M8330,M8310
D2R  PULSE-LA-ADDR-H      KC8-EA                          M8310
D2S  STOP-L               M8330,KC8-EA                    M8330
D2T  GND                  PSU                             ALL
D2U  KEY-CONT-L           KC8-EA                          M8330,M8310
D2V  SWITCH-L             KC8-EA                          KC8-EA
 
Thank you, I was looking for something like that after reading the bus documentation in the Small Computer Handbook.

I wish I had the knowledge to expand that table to add the voltage levels as well as a good description of each signal.

Nice work!!!
 

Thanks. Yes, I've seen that diagram, though I didn't notice that it had signal names as well as pin numbers.
It can help me with checking the signal names.

But it's not a list or table. I was after something made of text - that can be read, edited, sorted etc.
One purpose of my list could be as an aid to automating the production of a diagram such as that.
(something similar was the motivation to create it)


Use of the list for automation would benefit from a type/class field, as I mentioned earlier.
I'm thinking: POWR, BUSS (or ABUS, DBUS?), CTRL, MISC, RSVD (trying to keep everything upper case)
Any thoughts?
 
But it's not a list or table. I was after something made of text - that can be read, edited, sorted etc.
One purpose of my list could be as an aid to automating the production of a diagram such as that.
(something similar was the motivation to create it)

Use of the list for automation would benefit from a type/class field, as I mentioned earlier.
I'm thinking: POWR, BUSS (or ABUS, DBUS?), CTRL, MISC, RSVD (trying to keep everything upper case)
Any thoughts?

Indeed, it's not plain text, or a table. One can extract the text and edit it up into a table, but that's work.

One issue that I run into all the time with re-drawing the schematics and such, is that the CAD software doesn't allow blanks in the names, so I have to rename "SWITCH L" to "!SWITCH" (like "SWITCH", but with an overbar) or "SWITCH_L". Likewise with names like "SWITCH (0) L", etc.

I do think it would be interesting to put a class/type field. Steve Lafferty did some work a while back to understand the Omnibus signal classes: http://tronola.com/html/ram_for_pdp-8e.html

Vince
 
I've updated my Omnibus Signals List, fixing some errors, and adding three new fields.
Two of these fields refer to information contained in Chapter 9 of the "Small Computer Handbook 1973"
The new fields are:-
* A 2 digit "Load Driver" that indicates the Load and Driver types, as per those shown on ch9 p8. ("A" is type 10)
* An 8 character "signal type" of arbitrary strings that I've made up to try to classify the signals into groups.
* A 2 digit number that indicates the page in chapter 9 that best describes the signal.

Note that there are errors and inconsistencies in the handbook. In different places:-
* Some signals are described as both active low and active high. ("?" in signal name)
* Some signals have slightly different names.
* There is no driver type 7

Here is the updated list:-
Code:
Pin  Signal             LD  Type      Source                          Destination                                Page
A1A  TP                 28  Special   n/a                             Not bussed                                 07
A1B  TP                 28  Special   n/a                             Not bussed                                 07
A1C  SPGND              00  Power     PSU                             ALL                                        07
A1D  MA00-L             38  MemAddr   M8360,M8300                     KC8-EA,M8330,M8300,G227                    21
A1E  MA01-L             38  MemAddr   M8360,M8300                     KC8-EA,M8330,M8300,G227                    21
A1F  GND                00  Power     PSU                             ALL                                        07
A1H  MA02-L             38  MemAddr   M8360,M8300                     KC8-EA,M8330,M8300,G227                    21
A1J  MA03-L             38  MemAddr   M8360,M8300                     KC8-EA,M8330,M8300,G227                    21
A1K  MD00-L             28  MemData   M8300,G104                      KC8-EA,M8330,M8310,M8300,G104,M8350        19
A1L  MD01-L             28  MemData   M8300,G104                      KC8-EA,M8330,M8310,M8300,G104,M8350        19
A1M  MD02-L             28  MemData   M8300,G104                      KC8-EA,M8330,M8310,M8300,G104,M8350        19
A1N  GND                00  Power     PSU                             ALL                                        07
A1P  MD03-L             28  MemData   G104,M8300                      KC8-EA,M8330,M8310,M8300,G104,M8650,M8350  19
A1R  DATA00-L           48  I/OData   KC8-EA,M8350,M8300,M8360        KC8-EA,M8330,M8300,M8350,M8360             22
A1S  DATA01-L           48  I/OData   KC8-EA,M8350,M8300,M8360        KC8-EA,M8300,M8350,M8360                   22
A1T  GND                00  Power     PSU                             ALL                                        07
A1U  DATA02-L           48  I/OData   KC8-EA,M8350,M8300,M8360        KC8-EA,M8300,M8350,M8360,M8330             22
A1V  DATA03-L           48  I/OData   KC8-EA,M8350,M8300,M8360        KC8-EA,M8300,M8350,M8360                   22
A2A  +5V                00  Power     PSU                             ALL                                        07
A2B  -15V               00  Power     PSU                             ALL                                        07
A2C  GND                00  Power     PSU                             ALL                                        07
A2D  EMA0-L             38  MemAddr   M8360                           KC8-EA,G104                                21
A2E  EMA1-L             38  MemAddr   M8360                           KC8-EA,G104                                21
A2F  GND                00  Power     PSU                             ALL                                        07
A2H  EMA2-L             38  MemAddr   M8360                           KC8-EA,G104                                21
A2J  MEM-START-L        20  ProgCons  KC8-EA                          M8330                                      22
A2K  MD-DIR-L           38  I/OCtrl   M8330,KC8-EA,M8360              KC8-EA,M8300,G104                          20
A2L  SOURCE-H           38  MemCtrl   M8330                           G227                                       23
A2M  STROBE-H           38  MemCtrl   M8330                           G104                                       23
A2N  GND                00  Power     PSU                             ALL                                        07
A2P  INHIBIT-H          38  MemCtrl   M8330                           G104                                       23
A2R  RETURN-H           38  MemCtrl   M8330                           G104,G227                                  23
A2S  WRITE-L?           38  MemCtrl   M8330                           G104,G227                                  23
A2T  GND                00  Power     PSU                             ALL                                        07
A2U  ROM-ADDR-L         38  MiscCtrl  M880                            M8310,G104,M880                            22
A2V  LINK-L             20  CPUState  M8310                           M8330                                      24
B1A  TP                 28  Special   n/a                             Not bussed                                 07
B1B  TP                 28  Special   n/a                             Not bussed                                 07
B1C  GND                00  Power     PSU                             ALL                                        07
B1D  MA04-L             38  MemAddr   M8360,M8300                     KC8-EA,M8330,M8300,G227                    21
B1E  MA05-L             38  MemAddr   M8360,M8300                     KC8-EA,M8330,M8300,G227                    21
B1F  GND                00  Power     PSU                             ALL                                        07
B1H  MA06-L             38  MemAddr   M8360                           KC8-EA,M8330,M8300,G227,M8300              21
B1J  MA07-L             38  MemAddr   M8360                           KC8-EA,M8330,M8300,G227,M8300              21
B1K  MD04-L             28  MemData   G104,M8300                      KC8-EA,M8330,M8310,M8300,G104,M8650,M8350  19
B1L  MD05-L             28  MemData   G104,M8300                      KC8-EA,M8330,M8310,M8300,G104,M8650,M8350  19
B1M  MD06-L             28  MemData   G104,M8300                      KC8-EA,M8330,M8310,M8300,G104,M8650,M8350  19
B1N  GND                00  Power     PSU                             ALL                                        07
B1P  MD07-L             28  MemData   G104,M8300                      KC8-EA,M8330,M8310,M8300,G104,M8650,M8350  19
B1R  DATA04-L           48  I/OData   KC8-EA,M8350,M8300,M8360,M8650  KC8-EA,M8300,M8650,M8350                   22
B1S  DATA05-L           48  I/OData   KC8-EA,M8350,M8300,M8360,M8650  KC8-EA,M8300,M8650,M8350                   22
B1T  GND                00  Power     PSU                             ALL                                        07
B1U  DATA06-L           48  I/OData   KC8-EA,M8350,M8300,M8360,M8650  KC8-EA,M8300,M8650,M8350                   22
B1V  DATA07-L           48  I/OData   KC8-EA,M8350,M8300,M8360,M8650  KC8-EA,M8300,M8650,M8350                   22
B2A  +5V                00  Power     PSU                             ALL                                        07
B2B  -15V               00  Power     PSU                             ALL                                        07
B2C  GND                00  Power     PSU                             ALL                                        07
B2D  INT-STROBE-H       16  DataBrk   M8330                           M8330,M8360                                16
B2E  BREAK-IN-PROG-L    28  DataBrk   M8360                           KC8-EA                                     16
B2F  GND                00  Power     PSU                             ALL                                        07
B2H  MA,MS-LOAD-CONT-L  28  DataBrk   M8360                           M8310                                      18
B2J  OVERFLOW-L         28  DataBrk   M8310                           M8360                                      27
B2K  BREAK-DATA-CONT-L  28  DataBrk   M8360,KC8-EA                    KC8-EA,M8310                               17
B2L  BREAK-CYCLE-L      28  DataBrk   M8360                           KC8-EA                                     18
B2M  LD-ADDR-ENABLE-L   28  ProgCons  KC8-EA                          KC8-EA,M8310                               24
B2N  GND                00  Power     PSU                             ALL                                        07
B2P  INT-IN-PROG-H      48  MiscCtrl  M8330                           M8310,M8330                                26
B2R  RES1-H             28  Special   n/a                             Reserved for DEC use on1y                  07
B2S  RES2-H             28  Special   n/a                             Reserved for DEC use on1y                  07
B2T  GND                00  Power     PSU                             ALL                                        07
B2U  RUN-L              07  CPUState  M8330                           KCS-EA,M8330,M8350                         27
B2V  POWER-OK-H         5A  MiscCtrl  PSU                             M8330,G104                                 28
C1A  TP                 28  Special   n/a                             Not bussed                                 07
C1B  TP                 28  Special   n/a                             Not bussed                                 07
C1C  GND                00  Power     PSU                             ALL                                        07
C1D  I/O-PAUSE-L        16  I/OCtrl   M8330                           M8330,M8310,M8650,M8350                    09
C1E  C0-L               28  I/OIntf   M8650,M8350,M8330               M8310                                      10
C1F  GND                00  Power     PSU                             ALL                                        07
C1H  C1-L               28  I/OIntf   M8650,M8350,M8330               M8310                                      10
C1J  C2-L               28  I/OIntf   M8350                           M8310                                      10
C1K  BUS-STROBE-L       19  I/OIntf   M8330,M8350                     M8310,M8330                                13
C1L  INTERNAL-I/O-L     28  I/OIntf   M8330                           M8650,M8350                                09
C1M  NOT-LAST-XFER-L    28  I/OIntf   M8350                           M8330                                      14
C1N  GND                00  Power     PSU                             ALL                                        07
C1P  INT-RQST-L         28  I/OIntf   M8650                           M8330,M8350                                11
C1R  INITIALIZE-H       5A  MiscCtrl  KC8-EA,M8330                    KC8-EA,M8330,M8310,M8300,M8650,M8350,M8350 28
C1S  SKIP-L             28  I/OIntf   M8650                           M8330,M8310                                11
C1T  GND                00  Power     PSU                             ALL                                        07
C1U  CPMA-DISABLE-L     28  DataBrk   M836                            M8300                                      16
C1V  MS,IR-DISABLE-L    28  DataBrk   KC8-EA                          M8330,M8310,M8360                          18
C2A  +5V                00  Power     PSU                             ALL                                        07
C2B  -15V               00  Power     PSU                             ALL                                        07
C2C  GND                00  Power     PSU                             ALL                                        07
C2D  TP1-H              16  Timing2   M8330                           M8310,M8330,M8350,M8360                    27
C2E  TP2-H              16  Timing2   M8330                           M8310,M8330,M8350,M8360                    27
C2F  GND                00  Power     PSU                             ALL                                        07
C2H  TP3-H              16  Timing2   M8330                           M8310,M8330,M8650,M8350                    27
C2J  TP4-H              16  Timing2   M8330                           KC8-EA,M8310,M836                          27
C2K  TS1-L              16  Timing1   M8330                           KC8-EA,M8330,M8310,M8350,M8360             27
C2L  TS2-L              16  Timing1   M8330                           M8310,M8360                                27
C2M  TS3-L              16  Timing1   M8330                           KC8-EA,M8310,M8350                         27
C2N  GND                00  Power     PSU                             ALL                                        07
C2P  TS4-L              16  Timing1   M8330                           KC8-EA,M8310,M8360                         27
C2R  LINK-DATA-L        28  MiscCtrl  M8330                           M8310                                      24
C2S  LINK-LOAD-L        19  MiscCtrl  M8330                           M8310                                      24
C2T  GND                00  Power     PSU                             ALL                                        07
C2U  IND1-L             28  ProgCons  KC8-EA                          M8330,M8310                                26
C2V  IND2-L             28  ProgCons  KC8-EA                          M8330,M8310                                26
D1A  TP                 28  Special   n/a                             Not bussed                                 07
D1B  TP                 28  Special   n/a                             Not bussed                                 07
D1C  GND                00  Power     PSU                             ALL                                        07
D1D  MA08-L             38  MemAddr   M8360,M8300                     KC8-EA,M8330,M8300,G227                    21
D1E  MA09-L             38  MemAddr   M8360,M8300                     KC8-EA,M8300,G227                          21
D1F  GND                00  Power     PSU                             ALL                                        07
D1H  MA10-L             38  MemAddr   M8360,M8300                     KC8-EA,M8300,G227                          21
D1J  MA11-L             38  MemAddr   M8360,M8300                     KC8-EA,M8300,G227                          21
D1K  MD08-L             28  MemData   G104,M8300                      KC8-EA,M8330,M8310,M8300,G104,M8650,M8350  19
D1L  MD09-L             28  MemData   G104,M8300                      KC8-EA,M8330,M8310,M8300,G104,M8650,M8350  19
D1M  MD10-L             28  MemData   G104,M8300                      KC8-EA,M8330,M8310,M8300,G104,M8650,M8350  19
D1N  GND                00  Power     PSU                             ALL                                        07
D1P  MD11-L             28  MemData   G104,M8300                      KC8-EA,M8330,M8310,M8300,G104,M8650,M8350  19
D1R  DATA08-L           48  I/OData   KC8-EA,M8350,M8300,M8360,M8650  KC8-EA,M8300,M8650,M8350                   22
D1S  DATA09-L           48  I/OData   KC8-EA,M8350,M8300,M8360,M8650  KC8-EA,M8300,M8650,M8350                   22
D1T  GND                00  Power     PSU                             ALL                                        07
D1U  DATA10-L           48  I/OData   KC8-EA,M8350,M8300,M8360,M8650  KC8-EA,M8300,M8650,M8350                   22
D1V  DATA11-L           48  I/OData   KC8-EA,M8350,M8300,M8360,M8650  KC8-EA,M8300,M8650,M8350                   22
D2A  +15V               00  Power     PSU                             ALL                                        07
D2B  -15V               00  Power     PSU                             ALL                                        07
D2C  GND                00  Power     PSU                             ALL                                        07
D2D  IR0-L              00  CPUState  M8310                           KC8-EA,M8330,M8310                         23
D2E  IR1-L              00  CPUState  M8310                           KC8-EA,M8330,M8310                         23
D2F  GND                00  Power     PSU                             ALL                                        07
D2H  IR2-L              00  CPUState  M8310                           KC8-EA,M8330,M8310                         23
D2J  F-L                38  CPUState  M8310                           KC8-EA,M8330,M8310                         24
D2K  D-L                38  CPUState  M8310                           KC8-EA,M8330,M8310                         24
D2L  E-L                38  CPUState  M8310                           KC8-EA,M8330,M8310                         24
D2M  USER-MODE-L?       28  MiscCtrl  USER                            KC8-EA,M8330                               28
D2N  GND                00  Power     PSU                             ALL                                        07
D2P  F-SET-L            28  MiscCtrl  M8310                           KC8-EA,M8330,M8310                         24
D2R  PULSE-LA-H         5A  ProgCons  KC8-EA                          M8310                                      25
D2S  STOP-L             28  MiscCtrl  M8330,KC8-EA                    M8330                                      25
D2T  GND                00  Power     PSU                             ALL                                        07
D2U  KEY-CONTROL-L      28  ProgCons  KC8-EA                          M8330,M8310                                25
D2V  SWITCH-L           28  ProgCons  KC8-EA                          KC8-EA                                     26



Because I like writing software, and have too much time on my hands, I've written an "Omnibus Signals Browser" to present the signals information above in a variety of ways. (The program is for Windows only)
The intention is to help one become familiar with the Omnibus , to help when debugging Omnibus signal issues, and as an aid when designing boards to be used with the Omnibus.

Firstly, a simple display of the list:-

Click image for larger version  Name:	OBSB-1.png Views:	0 Size:	94.8 KB ID:	1226901


Checkboxes for each of the assigned "signal types" allow for highlighting groups of signals:-

Click image for larger version  Name:	OBSB-1a.png Views:	0 Size:	103.7 KB ID:	1226902
For those that find my colour-blindness induced colour scheme somewhat garish, ctrl-clicking a checkbox opens a dialog to change its colour.


The checkboxes can be used in a similar way for the "Load/Driver" signal attribute:-

Click image for larger version  Name:	OBSB-1b.png Views:	0 Size:	98.9 KB ID:	1226903


The list can be sorted on any of the columns:-

Click image for larger version  Name:	OBSB-1c.png Views:	0 Size:	107.3 KB ID:	1226904


An overall view of the Omnibus is shown in the Backplane display:-

Click image for larger version  Name:	OBSB-2.png Views:	0 Size:	75.8 KB ID:	1226905 Clicking any of the signals shows its other information at the bottom of the form.


The edge connector view shows the physical signal location on board edge connectors:-

Click image for larger version  Name:	OBSB-3.png Views:	0 Size:	87.3 KB ID:	1226906


Ctrl-Clicking or Double-clicking any of the fields in the forms described above will switch to the embedded PDF viewer for chapter 9, positioned at the page that describes the signal:-

Click image for larger version  Name:	OBSB-5.png Views:	0 Size:	210.5 KB ID:	1226907


The PDF viewer can be floated as a separate window for convenience:-

Click image for larger version  Name:	OBSB-6.png Views:	0 Size:	597.1 KB ID:	1226908

The program is in a RAR file available at:-
https://www.filehosting.org/file/det...sBrowserV1.rar

(Included extract of Chapter 9 of the "Small Computer Handbook 1973" Courtesy of Bitsavers)

Any comments, corrections or suggestions for any of the above are most welcome...
 
Your OmnibusBrowserV1.rar file won't open with WinRAR or WinZIP. Please consider making it available as a ZIP file?

[update: Right-click and save downloads a .RAR file with the right name, but a 10KB file size should've been a clue that something wasn't quite right. You need to 'click through' on that URL and fill out a form that harvests your email to send you another link to download the correct .RAR file (which is ~4.4MB).

This .RAR file does extract just fine, but trying to run the .EXE file gives:

ob2.PNG

Maybe there's a simple fix (register a .DLL)? ]

Looks like it could be quite a useful tool for troubleshooting.
I get the impression V1 only includes signals for the original 4 connectors (A,B,C,D).

I run a KK8-E board set with a BA8-C hex expander box which has hex options (KT8-A, RL8-A, FPP8-A, MS8-CD, etc...) Similar idea as the 8A-420, 8A-620, 8A-820 configurations.
For V2, please include signals for the E connector (used on hex boards). The E connector signals are documented on p. C3 of the pdp8/a miniprocessor users manual.

If you don't already have it, the DEC_STD_157_OMNIBUS_Specification document may be of interest.
 
Last edited:
Your OmnibusBrowserV1.rar file won't open with WinRAR or WinZIP. Please consider making it available as a ZIP file?

Are you sure?
I just checked that both WInRAR V6.01 and 7-Zip 19.00 can open both the original RAR that I uploaded, and a copy that I downloaded via the link.

Has anyone else tried it?
Success or problems?


I get the impression V1 only includes signals for the original 4 connectors (A,B,C,D).

Yes. I was only thinking of 8/E/F/M for this, because I'm just starting to play with my 8/F.

But you're right, it should be extended to cover the 8/A as well (if the extra pins follow some sort of a standard - ie: common to all hex boards that could go there).
And I have an 8/A as well, so I'm motivated to do it. Just may not be soon.

I'll look at the documentation links you've provided, and also see what other suggestions come along...

Thanks for the feedback.
 
I downloaded and opened the files successfully using 7-Zip 18.01(x64), though my email and I found filehosting.org to be a bit sketchy. Emails without senders are (literally) not well received. All that aside, very useful information in a helpful format.

Thanks!
 
I downloaded it on my Mac and it opened fine. I'll now move it to my NAS drive for access from my Windows machine later. Yes, very useful info. Thank you for taking the time to provide it.
 
So best I can tell this is not totally unexpected with custom code being seen by MalwareBytes heuristic machine learning detection module. So probably a false positive.
 
Bit Defender did not have a problem with the program.

The program itself is very nicely done and informative.
 
Sorry for the delay in replying, had a couple of higher priority interrupts. (the worst being my hot water tank has sprung a major leak and was wasting heaps of water and electricity for several hours before discovered, I hope to replace it tomorrow)

The program is written in Delphi, and I've seen MalwareBytes complain about other Delphi programs I've written as well - they are false positives.
Of course, please be assured that there is nothing in any way malicious in this program.

Thanks for the positive feedback on the program!
I was expecting comments about my mistaken and non-standard pin numbering, eg: "C2H" instead of "CH2".
I actually like it better, but it's not the DEC standard, so I'll fix it in the next version.

Also for the next version I've added a button to write the "edge-connector" view to a file for editing or printing. It includes a couple of columns in the center, where one can edit/write a mark to indicate that a particular board uses that pin.

I did that for the M8650, and it helped illuminate how the board uses the Omnibus. After the pin list I manually added a summary showing which pins were used, grouped as per the "signal types" used in the program.

But I found that process a little error prone, so I'm thinking of putting the marking procedure in the program, and having it produce the pin listing file with the marks already inserted, and the summary by group generated automatically. (I'll shortly post the M8650 list that I made in another thread)
 
Yes, iIt would be best if you could just right-click a link and "save link as", without the email crap.
FileHosting was the first free hosting service that seemed OK. I'll look further into the others (any suggestions?).
 
ob2.PNG
Any suggestions on how to resolve this error message when I try to run the .exe ?
 
I'm fairly sure that an OLE error must be something to do with the AcroPDF ActiveX control for displaying the PDF.

Do you have Adobe Acrobat installed?
Is there anything about your system that could affect ActiveX controls?
 
Thanks.
.. Do you have Adobe Acrobat installed? ..
That's what it wanted. I have a different PDF reader installed, but apparently it needs the Adobe one.

Curious if C1R INITIALIZE-H is supposed to have M8350 listed twice in the destination field?
 
Good to hear it's good now!
The embedded Acrobat viewer was a pain to get working properly, but it's almost ubiquitous, so it was a reasonable choice.
I've recently switched to SumatraPDF, which is simple, and quite good for panning around when zoomed in on a schematic. Embedding SumatraPDF might be an option in a future version.

Those source & destination fields came from Appendix B of the "PDP-8/e/f/m MAINTENANCE MANUAL VOLUME 1", and were subject to OCR errors, and my programming/editing errors.
And you are correct, there is an error on C1R: The second M8350 should be M836.
(nothing in either of those two fields should be duplicated, but may appear in both).
I'll fix it, but for now, you can just edit the text file:-
C1R Sources: KC8-EA,M8330
Destinations: KC8-EA,M8330,M8310,M8300,M8650,M8350,M836

But I'm wondering if those two fields should not be changed to more general and readily understood forms such as: CPU, TimingGen, Console, Memory, I/O, DataBreak, etc?

And looking at that appendix, we see that DEC used "C1R" rather than "CR1". (which is where I adopted that format from)
So maybe the two formats are interchangeable, and the program can be left as is in that regard?
 
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