Problem with PiDP8i since serial option installation

Thomas Riesen

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Jan 14, 2021, 3:01:13 PM1/14/21

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First a big Thank you for the add in this group!

A few yeasr ago I built the kit based on the pcb version 2.2. It worked well till I installed yesterday the serial interface option.

I made the given changes, removed R23/R24 on my Pi 2 Model B, cutted the traces on J_COL1 / J_COL2 and installed new jumpers joining 1+2.

Installed the two resistors 300R on position X and a 680R on position X*2 (don't have a 620R, hope 680R is ok). Installed the same nice, cheap

blue serial/USP converter like shown in the manual.

The Pi starts and shows the start messages, but when the LED's go on, only "à" become displayed endless on the Terminal (see picture). My serial paramters are 115200,8,N,1.

A second problem is, since I made the changes on the Pi and on the board, the "Load Address" switch doesn't work, nothing hapen when I toggle the switch.

And hints what's to do?

PiDP8i_01.JPG

Warren Young

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Jan 14, 2021, 5:03:50 PM1/14/21

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It's not clear which serial mod you're talking about, but I think you need to reconfigure and rebuild with --serial-mod or possibly --alt-serial-mod per the software docs.

Thomas Riesen

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Jan 14, 2021, 5:22:36 PM1/14/21

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So, I have to enter this command:
$ ./configure --serial-mod

What do you mean with not clear which serial mode? I described my already done changes ... what's not clear?

Thank you

Thomas

Warren Young

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Jan 14, 2021, 8:09:12 PM1/14/21

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On Thursday, January 14, 2021 at 3:22:36 PM UTC-7 gast...@gmail.com wrote:

So, I have to enter this command:
$ ./configure --serial-mod

Or --alt-serial-mod, yes. There are at least two "serial mods," and I don't know which one you've done.

Then build and install the software following the instructions elsewhere on that same page.

I described my already done changes ... what's not clear?

One of the two was posted on Oscar's pages for years, but was gone the last time I tried to go looking for it, apparently because he's trying to push everyone to the USB crossover method, even though that doesn't actually cover all of the cases where someone would want a real RS-232 serial port.

Then there's the James L-W method, which is different again.

While I could cross-reference your instructions against those instructions, one of which I may not even be able to find any more, you could just post the URL of the instructions you followed. Then it'd be clear to all.

Thomas Riesen

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Jan 15, 2021, 3:45:58 AM1/15/21

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Thank you for your help, I will try this ...

I made the modification like Oscar described, as mentioned, I removed the R's on the Pi and installed the jumpers 1-2 on the pcb.

Thomas Riesen

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Jan 25, 2021, 10:02:38 AM1/25/21

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I still have big problems to bring my Raspi correct up and running. Is there really nobody who provides me a running Image to use the serial port, adapted according to Oscars version (removed R23/24 on Raspi)

I have a Raspi 2 Model B.

Thank you for your help?

Obsolescence

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Jan 26, 2021, 6:51:39 AM1/26/21

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Thomas,

After the serial mod, you need to recompile the simulator binary so it know about the new assignment of GPIO pins.

Follow the README.md file in the pidp8i dirctory. I don't have a PiDP-8 at hand, but I went through the procedure on my Ubuntu laptop to verify up to the point where the laptop misses the physical hardware.

In the pidp8i install directory (~/pidp8i) just enter

./configure --serial-mod

then, do

make && sudo make install

and you have the pidp8i software reconfigured for the new (serial-modded) hardware setup.

Kind regards,

Oscar.

Thomas Riesen

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Jan 27, 2021, 1:36:33 PM1/27/21

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Oscar,

Thank you so much for your help! Now the serial port and also the switches work well!!! Sorry for my weak knowledge about the Raspi ...