Bridgeport Series I BOSS electronics.

[HackerMechTech]

Hi All:

I was trying to figure out just what I have electronics wise so I ripped out the CPU board of my BP S1 and ... Hey, this looks like the old PDP-11 Bus. I see CPU DEC 3015D. Well it's DEC. I do a little internet search .... YES this is a PDP-11! Okay I can work this bus. Now, Do I need to back up the ROM as it's coming to 30 years old.

Okay I thought that the BOSS series of computers were 68000 based, since mine is a PDP-11 based machine does anyone know what series of BOSS I have? The machine serial # places it as being born in 1980. Carter era....

Andrew

[Al_The_Man]

Way back I retrofitted a couple of boring mills that were PDP-8 run.
Not bad for 1965 data processing units running a CNC machine.
Al.

[HackerMechTech]

PDP-8 ... I donno sounds kinda boring! Sorry could not resist. Seriously I see this machine running G code and servo-ing motors. No need for anything big. I can see small limits of the G code I can run on this thing. But I'll start small then start a re-engineered CPU board. First things first get this beast running.

The ultimate hack would be to mill the replacement pro-boards on the machine they are going into. Machine ... make thyself!

So given my limited computing machinery any ideas on what version of BOSS I'm running?

You can do a lot of damage with a PDP-8.

Andrew

[machintek]

The digital Equipment Company used a KD11F board in the BOSS 3 and 4.
A KD11L was used in the BOSS 5 and 6.
The actual BOSS level was determined by the ERS board which had the BOSS software burned onto a PROM.
Search the posts. I wrote up a lot longer history of these machines and what is inside of them.

George

[HackerMechTech]

I have an LSI-1, M7264 for the CPU Board. So what version of BOSS would this be?

Andrew

[HackerMechTech]

To answer my own question. I found this resource.

ftp://metalab.unc.edu/pub/academic/c...ield-guide.txt

The M7264 is a KD11-F Q 11/03 processor with 4-Kword MOS RAM

Sooo it looks like I have a BOSS 3 or 4. Okay making progress.

Andrew

[HackerMechTech]

... Another question. Does the BOSS 3 or 4 run g code? I have this vague recollection of reading that below BOSS 5 g code was not the lingua franca.

Andrew

[machintek]

ALL BOSS machines were strictly G code machines.

George

[HackerMechTech]

Excellent! I've found a lot of links to DEC PDP 11 stuff. The PDP-11 is the base computer system for the Bridgeport Series I. I've found a lot of general docs that would help in understanding the system, but is a tad esoteric. If you folks are interested I can put together a list of links.

I spent some time with the bridgeport boards and they are very simple 7400 logic circuits. I'll be reverse engineering these soon, so the mods can begin.

[kdhBOSS5VRAM]

It would be great if you could figure out a way to increase the stock memory on these. I still use mine in the stock configuration and it would be nice to have more memory without using a BTR system. Good luck on your adventures.

Kevin

[HackerMechTech]

Hey Kevin:

I think the best we could do with the system as is would be a 64k of RAM upgrade. And we'd have to break into the code and reset the memory management limits. All can be done esp since there are pdp-11 emulators out there. I haven't figured out where the code is kept. I don't see any windowed EPROM's on board, so I figure that the code is kept on a perm ROM.

If I were to keep the pdp-architecture, I'd first have to read out the rom. Okay my logic analyzer can do that. Then disassemble the code. Okay we can do that too. Now for hardware.....

At first glance at the problem, I'd take the pdp-11 on a chip projects out there, where you get the pdp-11 system of your choice on a FPGA. 1 this would allow the system to grow as needed and you could run at speeds undreamed of in the 1970's. 2 if the memory paging is not too awful, you could easily expand the memory capability into the 16MB range very easily. Then mount that on a PCB that meets the mechanical needs of the BUS.

That would be fun and cool, but it would mean modding DEC assembly using archaec tools.

My eventual mod would be to use something like the TS-7300, 32 bit controller with FPGA, full 100 base T, as many rs-232's as grandpa ever needed and 100's of MB of RAM. Or, just a TCP/IP interface and run the show from a PC (Yeah! THAT'S THE TICKET!). First off, tho, I need to get my beastie up and running and I'll spoon feed it.

As for me, I'm just not going to sleep well at night until I encode this beastie and calibrate it. I'm a controls and accuracy weenie.

Okay, I'll setup up a web page with the project this weekend. I spent some time exploring the boards. I need to find out if I'll be violating the DMCA if I published schemos of the boards and write ups on the functionality.

Andrew

[kdhBOSS5VRAM]

Andrew,
Looking forward to your website on the project. I think stock these old machines had about 12K of memory which way back was probably plenty for what needed to be done with all the subroutines and such. Seems like most of the stuff I do always ends up being 3-D and takes huge amounts of memory. A sample:

YouTube - Bridgeport Series 1 BOSS 5 CNC 3D Test

I have an old BTR system that I've used a couple times but even that seems to be limited to about 80K a program for some reason.

YouTube - Bridgeport BOSS 5 DNC Engraving

That's plenty for most things but I'm used to being able to download almost unlimited files on the machines I use at work. I'm a CNC programmer-machinist not an EE so I understand some of what you were saying. I know just enough to be dangerous with electronics and computers.

Kevin