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PDP11 - LSI11/02 and RQDX3

If you have a second serial port (DL11 compliant - e.g. DLV11-J) I would be inclined to use a serial-based TU58 emulator initially.

In fact, you can drive the TU58 emulator as a virtual serial disk - so you can run the XXDP diagnostics this way.

Increase the baud rate of the serial port to the MAX and you will find that an emulated TU58 drive is faster than a real floppy drive!

Beware of cheap RS232 to USB converters though...

Dave
 
daver2 said:
If you have a second serial port (DL11 compliant - e.g. DLV11-J) I would be inclined to use a serial-based TU58 emulator initially.
Click to expand...
Unfortunately, I was not able to get this working :-(

My setup is 2 seperate "better quality" USB to RS232 converters, one linked to TU58fs-bootloader, the other one to TU58fs.

Unfortunately, the bootstrap is not working either or I still make mistakes.

1711816257253.png

You can download the assembler sources from retrocomp as .mac file instead, but no reaction from the PDP11 either.
The console reacts to "deposit all" but running the bootloader with <010000G> shows no reaction....

Maybe you know whats goeing wrong?

1711816333781.png
1711816448947.png
 
Can we try walking before we run?

Have you checked the serial port out using ODT?

Try writing a character from ODT through to the PC and vice versa (using a terminal emulator of some sort on your PC).

Dave
 
Isn't port 3 the console port?

Not got my documentation handy at the moment.

What about the other terminal port for the TU58 emulator?

Dave
 
Is this the same bootstrap code that your are using?

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forum.vcfed.org

The serial port is expected to be at I/O address 176500.

There is also some useful information here: https://www.pdp-11.nl/ba11-boxes/ba11va/ba11va-info.html.

I see you are using TU58FS instead of TU58EM. Perhaps try both.

You need a console port (for ODT) and a serial port at 176500 to drive the TU58 emulator. The DLV11 needs to be configured for the same serial parameters as you are setting the PC TU58 emulator to.

Dave
 
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Thanks a lot for your help. I think my config is correct. The module base address is 176500, Port 3 is configured as console, Port 2 is connected to the TU58fs. I will check with TU58EM.
 
Hmm,

I think port 3 is the system console and port 0 is at 176500. Not port 2. I maybe wrong though (I haven't got access to my documentation at the moment).

Please check the documentation to be absolutely sure...

EDIT: 176500 = Channel 0 = J0.

Dave
 
Last edited:
If I remember my DLV11-J's, port 0 was 176500/300 then 1 was 176510/310, 2 was 176520/320 and 3 was the normal console port/60

Try port 0 for the TU58 thing.
 
Thanks a lot for your advice, that is highly appreciated.

Now my setup seems to work - Port 3 = console, Port 0 (obviously 176500/300) used to connect to TU58EM:

1711838704791.png
 
Just out of interest, what TU58 emulator command line are you now using and what image file are you booting?

Dave
 
Hi Dave, thanks again for your support.

I started before keying in the bootstrap sequence the TU58EM with following command line:
1711840339609.png
The image file was just a random file from https://ak6dn.github.io/PDP-11/TU58/

I am wondering why the XXDP says I have 28kWords - is this the free space or do I have an issue with my 32kW memory board?
 
The top 8KB/4KW of address space is by default memory mapped I/O (notice the CSR address 176500, for example, falls in that space), so it's expected that the RAM there is unusable.
 
I have been looking around for DU-device boot ROMs.

Unfortunately, the only ones I can find are 16KW - and your bootstrap board only has 4KW of EPROM space by the looks of it.

I also haven't been able to find any source code (other than the file I found - but that is not a true bootstrap) for a stand-alone DU bootstrap.

I could try and build a set of bootstraps for our own PDP-11 software and see how small I can get it - but (from what I remember) you need an MRV11-C or an MRV11-D to hold it.

Somewhere, I have the MSCP protocol manual. I am going away on a business trip in a couple of weeks - A DU bootstrap would be a useful project whilst sitting in the hotel!

EDIT: Online at: https://vt100.net/dec/aa-l619a-tk.pdf.

Dave
 
Google is my friend today...

Not a stand alone bootstrap (yet) but not too difficult to hack...

Dave
 

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