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Build your own PDP 8I, Part 2..

Marty

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Hi All;

I have tried to run programs from a Link that (I think) M-Thompson gave me..
I have run the first of Group 1 instructions, and it fails one instruction -- BSW 7002..
But it passes the following instructions -- CLA, CLL, CMA, CML, RAR, RAL, RTR, RTL, IAC and HLT..

THANK YOU Marty
 

antiquekid3

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That's a good thing, Marty! The 8/I didn't support this instruction, only 8/E and later. Probably wouldn't be hard to add it. At the moment, you do need this instruction to get my SerialDisk software working on an 8, but I'm guessing you're still a few months out from having two working serial ports. And congrats on the excellent progress! It's very inspirational. Maybe once you've debugged yours sufficiently, we can generate a known good schematic and do a board layout.

Kyle
 

Marty

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Hi All;
Thank You, Jack for Your suggestion.. "" After all, it's summer and you must have lots of free time. ""
Not as much as You might think, there are alot of Trailer Issues, that have come up since the flood, that just now are showing up.. And need fixing and constant attention..
I Looks like the ISZ Instructions is working, I am waiting for the test to finish, to also evaluate the SZA instruction as well..
It partially has ION/IOFF working, but there needs to be some wiring changes in that section, as well as numerous other stuff before I/O would work at all.. There would need to be another Socket added for the I/O signals that would be put on the Memory Board, turning it into a Memory/I-O Board..
Kyle, Thank You for the very Kind words and information on the BSW instruction..
"" but I'm guessing you're still a few months out from having two working serial ports. ""
It shows how to wire up One Port, but NOT two Ports, it does give some hints, but nothing more..
But, at present, even One Port would be of a Great Help..
I am looking at the I/O circuit and trying to decide what I need to do and in what way I need to do it..
I have just downloaded "Introduction to Programming" PDP 8 version.. And will be trying things out with it as a guide..
I have speeded it up, I changed the 555 timer timing resistors from 100k to 10K and now to 1K, in comparison to before it is now flying..

Here are a couple of pictures..

001.jpg 002.jpg

THANK YOU Marty
 
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Marty

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Hi All;

I looked at Kyle's program and found out I had made a copy Error.. I have Entered the Correct program into the computer, and it did not work.. Upon further inspection, I found that 'now' the CML Instruction does not work, I will need to investigate..
It may need to have the OPGx Signal changed and or looked at.. While I am at it I will check CLL and CLA..
I got it to work, but I really didn't do anything.. I took off the wire from the pin and used a wire jumper to check it on both OPG1. Hi and OPG1.LO, and it worked on OPG1.Hi, like it was previously wired or so I thought.. I re-wired it and it now works..
I changed the program a little and now I need to find out Why SNL 7430 doesn't work.. Hopefully it is something simple..
It maybe the ISZ instruction, so this will need more looking into on Monday.. I had made a Mod to it and now that I temporally undid the Mod then there are other problems..

THANK YOU Marty
 
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pbirkel@gmail.com

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I have set up a folder with all LD12-related files in my possession at:

http://n8vem-sbc.pbworks.com/w/browse/#view=ViewFolder&param=LD12 PDP-8/I

I believe that at the moment you'll need to register in order to access that folder, but that's no worse than registering at VCF.

The N8VEM folks are micro-oriented, but wide-ranging. Possibly some folks here already know of them. If not, maybe you'd like to?

See overview at: http://n8vem-sbc.pbworks.com/w/page/4200908/FrontPage

(Note that there's a lot more going on there than depicted in that one photo! Dig around some ...)

And ... congratulations on your steady progress Marty :->!
 

antiquekid3

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Hi All;
Thank You, Jack for Your suggestion.. "" After all, it's summer and you must have lots of free time. ""
Not as much as You might think, there are alot of Trailer Issues, that have come up since the flood, that just now are showing up.. And need fixing and constant attention..
I Looks like the ISZ Instructions is working, I am waiting for the test to finish, to also evaluate the SZA instruction as well..
It partially has ION/IOFF working, but there needs to be some wiring changes in that section, as well as numerous other stuff before I/O would work at all.. There would need to be another Socket added for the I/O signals that would be put on the Memory Board, turning it into a Memory/I-O Board..
Kyle, Thank You for the very Kind words and information on the BSW instruction..
"" but I'm guessing you're still a few months out from having two working serial ports. ""
It shows how to wire up One Port, but NOT two Ports, it does give some hints, but nothing more..
But, at present, even One Port would be of a Great Help..

Marty, I may be mistaken, but I think Jack was referring to my infinite amount of free time now that I'm off from school for the summer. Unfortunately, I've moved up to Baltimore for the summer and am working full time, which doesn't give me too much time for hobbies.

Mmm - and maybe deal with ION/IOFF?? :>)
After all, it's summer and you must have lots of free time.

To add ION/IOFF support for SerialDisk? If so, does anyone really need support for that? I am having trouble thinking of a use case. During block transfers, the PDP-8 isn't doing anything but handling transfers, and with the speed of the computer SerialDisk is running on, it should never have any trouble keeping up, even at 230.4k baud, which, besides the Omni-USB board, is the fastest I've ever run SerialDisk at.

A few things that are in the works are a parallel version utilizing a DR8-E connected to a microcontroller, as well as getting SerialDisk ported to the DECmate series. Still figuring out the darned serial port there. I'll start a thread of SerialDisk discussion separately, though.

Michael, I will try to look into replacing BSW with a few RTR/RTL/RAR/RALs and such. I think I have enough room to do that now, even in the cramped system handler. Another thing in the works is modifying the non-system handler to support four RK05 images, versus the current two. That'll also require a few minor mods to the server, but again, those are quite minor and involve some copy-paste-modify.

Kyle
 

pbirkel@gmail.com

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Hi All;
Thank You, Pbirkel for posting these online for others to have access to, and sharing these files with Everyone..

THANK YOU Marty

Well, don't thank me. They come from someone close to one of the book authors. I've been slow to post them because there has been minimal interest in them from folks here :-<. Anyway ...

My objective remains to move the wire-list(s) -- which I've been repeatedly assured *is* correct (one is simply the inverse of the other) -- to a PCB tool and eventually to fabricate a PCB as well as the exactly-corresponding schematic. Your difficulties using those wire-lists are quite worrying. I remain hopeful that when you have a working implementation your notes will be sufficient to identify where there may be errors in the source materials.

Note that Oscar V., over on the N8VEM forum, has expressed interest in putting together a front panel-derivative from his PiDP-8 project. That would be quite nice, but there are lots of questions to be answered first ...

Keep on wrapping ... (and, alas, unwrapping).
 

Marty

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Hi All;
PBirkel, there ARE differences between the two lists, so far they are write in on the IntList versus the ExtList, but I have not had time to check everything between the two..
I will on Monday be checking to see if by eliminating one 7404 gate and changing one 7400 gate to a 7402 gate might make ISZ work..

THANK YOU Marty
 

pbirkel@gmail.com

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Hi All;
PBirkel, there ARE differences between the two lists, so far they are write in on the IntList versus the ExtList, but I have not had time to check everything between the two..
THANK YOU Marty

Not asking you to but ... could you provide a specific example(s)? I'd like to verify it/them for myself. These line printer listings are not-so-clear, and thus may be subject to misinterpretation. Would like to see if there's an objective discrepancy, please.
 

Marty

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Hi All;
PBirkel, No Problem.. I will List what I have of them Tomorrow, for You to Look at..
I think, but I don't know for sure, But, I think one is an Earlier listing and the other is a Later Listing..

THANK YOU Marty
 

Marty

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Hi All;

It doesn't work right with the Mod, but it looks very promising, I have an errand to do and so I won't be back till sometime between 10:00 and 11:00.. Then I can single step thru the various steps and see what/where the problem lies..

THANK YOU Marty
 

Marty

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Hi All;

I'm back.. I have tried a few variations, and I need to put them down on paper and make a list of what does what..
PBirkel, I haven't forgotten about Your request..

THANK YOU Marty
 

Marty

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Hi All;

I found a variation of something that seems to work with this program..

Address 0000 Data 0000
Address 0001 Data 7200
Address 0002 Data 3000
Address 0003 Data 2005
Address 0004 Data 7402
Address 0005 Data 5001

It Starts at Address 0001.. I will run continuously and Not Halt.. I think this is correct..
Next is Kyle's Program.. I will let You Know..

I does Not run Kyle's program, but it is not what one would think as to why..

Address 0000 Data 0000
Address 0020 Data 7320
Address 0021 Data 7010
Address 0022 Data 2000
Address 0023 Data 5022
Address 0024 Data 7430
Address 0025 Data 5027
Address 0026 Data 5021
Address 0027 Data 7004
Address 0030 Data 2000
Address 0031 Data 5030
Address 0032 Data 7430
Address 0033 Data 5021
Address 0034 Data 5027
Address 0035 Data 0000
Address 0036 Data 0000
Address 0037 Data 0000

I start it 0020 and the next instruction, which should show it at 0021, instead is at 0000 !!!!! Go figure..
I will put it into single step mode and see what shows up..
I re-assembled Kyle's program to start at 0001 instead of at 0020, but not any better.. I need to take a closer look at things..

THANK YOU Marty
 
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antiquekid3

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Marty, remember that locations 10-17 are autoincrement and will give very weird behavior if you reference them indirectly.
 

Marty

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Hi All;
Kyle, Thank You for the reminder, Which was Why I wanted to try it starting at 0001.. I was kind of thinking the same thing..
I will put it on the back Burner for awhile.. Maybe something will come to mind..

PBirkel, here is the first of the many differences between the two lists, (There will be many edits)..
Also, it may be Helpful to look at the Pages under Your copied PDF format for easier Viewing..

On the INT sorted List A10 (M16) (page 11) Shows pin 1 of the 7430 originally going to A45-6 (M10-6) it is crossed out and is wired to B47-3 (L8-3).. It is also wire to A98-10 (K19-10)..
Thereby eliminating Signal A0 from the equation.. When I first tried this, before finding the 'F' enable not working, the PDP 8i clone would not work with this signal missing.. I have not tried it since then, I will put it on my list to do..
On the EXT sorted list M16 (A10) (page 112) shows pin 1 of the 7430 going to M10-6 (A45-6) and K19-10 (A98-10)..

On the INT sorted List A11 (K4) (page 12) Shows pin 2 of the 7402 originally going to A12-9 (M12-9) and also to A43-9 (K2-9) which has been crossed out..
Also on the same page A11 shows pin 4 going to A11-3 (K4-3) and also to A43-11 (K2-11) which is crossed out and P1-60 is written in..
This Eliminates two of the Signals from G16, which when another mod is applied, will do the same thing only it will Simplify the circuit.. At this time I have Not applied this Change..
On the EXT sorted List K4 (page 74) shows pin 2 wired to M12-9 (A12-9) and also K2-9 (A43-9)..

On the INT sorted List A13 (M15) (page 14) pin 5 goes to A52-5 (K14-5) and has been written in (added) A36-3 (G16-3).. This is part of the above mentioned Mod..
On the EXT sorted List M15 (A13) (page 111) pin 5 goes to K14-5 (A52-5)..

On the INT sorted List A19 (E1) (page 20) pin 3 goes to C1-1 (J6-1) and has been written in (added) A21-1 (E15-1)..
Signal has been changed from F1 to F0.. I have implemented this change and it agrees with the Equations..
On the EXT sorted List E1 (A19) (page 3) goes to J6-1 (C1-1)..

On the INT sorted List A21 (E15) (page 22) pin 1, A33-13 (E11-13) is taken off and it is wire to A19-3 (E1-3)..
Signal has been changed from F1 to F0.. I have implemented this change and it agrees with the Equations..
On the EXT sorted List E15 (A21) (page 17) is wired to E11-13 (A33-13)..

More on the next posting..

THANK YOU Marty
 
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