RetroPrinter Support

Hi there,

I'm having problems with the Retroprinter on my ZX Spectrum +3. It works brilliantly with my Amstrad CPC6128 but every time I use the Lprint command in both +3 Basic and 48k Basic, nothing seems to be outputted to my Retroprinter device. I have posted previously on here and my Amstrad CPC issues were solved.

Is there anything I need to do additionally with my ZX Spectrum +3?

So far as I know, the Spectrum +3 and the Amstrad CPC6128 use the same printer edge connector (although I am not sure).

I had to have a quick look at the Spectrum+3 manual - https://worldofspectrum.org/ZXSpectrum1 ... 8pt21.html

LPRINT and LLIST are redirected to the printer port (at least in 128K BASIC - in 48K, I believe they still go to the expansion connector for the ZX Printer). However, you need to set the /root/config/auto_linefeed to Yes

Check if it is capturing anything in /home/pi/data/raw - it will not generate any output until there is a full page of A4

Hi,

I've changed the autofeed setting and I now get pdf files but I get googledegook instead of what I had initially written in +3 basic. I get the raw files. The data input light does not seem to light up like the Amstrad CPC did.

What next ?

Post examples of the output and what you are trying to print from BASIC - I am flying blind as I don't own a +3 Spectrum and not many people have a +3, and the AMSOFT PL-1 Adaptor

You may need to change the /root/config/bit_depth to 7

Hi.

Here is the first example attached. Before changing to 8.

It was supposed to say 'Hello spectrum 128'

I have changed it to 8. The RAW file and EPS files are being produced but not the PDF.

Can this be remedied?

OK so that looks not to be related to the 7 bits / 8 bits; so I am at a complete loss and you are basically asking me to figure out the issue completely blind

It looks as though it might be something peculiar about the Spectrum hardware - it could even be that the printer edge connector on the Spectrum+3 is worn or filfthy and needs cleaning. There is little information about the two printer edge connectors on the Spectrum and the Amstrad CPC, and after all, the Retro-Printer works with the Amstrad....

If the PDF is no longer being generated - how did you alter the /root/config/bit_depth file?

If you edit it in Windows - you have to be careful that you do not change the line endings from Unix !

Try :
cd /root/config
dos2unix *

Can you send the raw files and retrporinter.log file?

AmstradCPCcool wrote: Mon Oct 19, 2020 9:19 pm Hi there,

I'm having problems with the Retroprinter on my ZX Spectrum +3. It works brilliantly with my Amstrad CPC6128 but every time I use the Lprint command in both +3 Basic and 48k Basic, nothing seems to be outputted to my Retroprinter device. I have posted previously on here and my Amstrad CPC issues were solved.

Is there anything I need to do additionally with my ZX Spectrum +3?

Hi AmstradCPCcool,

I realise I'm replying to an old post, but I had the same issue so I wanted to add some more information!

The problem is due to a bug in the Spectrum +3 ROM. The system variable BANK678 is not initialised correctly - so the strobe signal (on pin #1 of the printer connector) is not set properly. This was corrected by Amstrad in the +2A (which came out after the +3) so most printers, including the Retro-Printer work with it as expected. If you are comfortable changing the ROM ICs in your +3 (and have access to an EPROM programmer etc.) then that would certainly fix the problem - that's what I did and now my +3 is printing quite happily!

The parallel printer port can't be used from 48K BASIC at all - that will only work with the expansion port-printers like the ZX Printer or Alphacom 32.

For a temporary fix, it's possible to enable printing in the v4.0 ROM with a couple of POKEs. Be sure to enter it on one line like so, otherwise the Spectrum will crash if you enter the POKEs separately. (Or it can be done within a BASIC program). [source: https://worldofspectrum.org/forums/disc ... ent_199071]

For a slightly more robust fix, POKE the following 11 bytes, starting from 23355:
This does the same thing, but preserves the "disable interrupt" instruction during ROM paging.

I also had a look at how we handle the STROBE signal on the Retro-Printer. Unfortunately, this would involve a hardware change to support what is, after all, a bug in the ZX Spectrum +3 ROM.