Usefulness of a MPS801 printer (?)

[orion70]

Here I am with the real printout of Minigrafik pictures. Unfortunately, the routine seems to mess things up a bit. In order to try the routine with the real MPS801, I used two MG pictures from my game "The Great Adventure", one hi-res with only two colors and one lo-res in shades of blue:



The result for the first image is readable, but some lines do not wrap, and the printout is shorter than the image:



The second output is even worse, no readable image here:



In this session, I used a SD2IEC device instead of the 1541, because I had to be sure the routine was free from typing errors. Mike?

[Mike]

Here I am with the real printout of Minigrafik pictures. Unfortunately, the routine seems to mess things up a bit. [...] The result for the first image is readable, but some lines do not wrap, and the printout is shorter than the image: [...]

This isn't caused by the hardcopy routine. As you might guess, there's nothing in it which could 'forget' about the necessary line breaks for no reason. Rather, I suppose this results from transmission errors on the serial bus. You already had some issues regarding line breaks, maybe there's some dodgy cabling involved. Also, some of the SD2IEC devices can't cope with another peripheral on the serial bus, as their output signal drivers are overloaded.

The second output is even worse, no readable image here:

Not really. First of all, the same issues here regarding line breaks. Second, I already wrote that the hardcopy currently is really only suited for B/W pictures (see: 'funny' results with multi-colour portions - and the second picture is *all* multi-colour!). It just happened to work out somehow a bit with the picture of Emma.

Take a look at the screen when the hardcopy has forced it to B/W: the black and white portions of the picture are mapped to 'stripy' areas (with %10 for white and %01 for black), while the two intermediary colours are mapped to %00 for the lighter and %11 for the darker colour.

I used this mapping of the colours not without reason: only %00 for background and %11 for the auxiliary colour can display all 16 colours. So this is the only way all combinations of colours can be selected as intermediary colours.

...

For the moment, there's not much we can do about this. I'll bring my own C64SD to my visit, so we can test with that one. It would be nice, if you could order two new serial cables in the meantime.

[orion70]

Thanks Mike. TBO, I was suspecting issues with the serial cable(s). I did not try the routine with the "old school" chain VIC->MPS801->1541.
The SD2IEC device, be it "classic" or the FE3, wants a direct power supply from the VIC. For this reason, I tried the routine with a serial Y-split cable, which is probably the source of the problem, as you pointed out. But I do have a couple of spare serial cables, so I'll try chaining the devices the old way, before pulling the 1541 out of the box again.
I did notice a strange behaviour in the Y-cable configuration, i.e., if I did not turn the printer on, the VIC didn't see the IEC drive (?device not present error).

[TBCVIC]

I remember back in the day, a friend of mine made a program that printed gray scale images on a matrix printer by writing the same line several times.
You would need an old ink ribbon with almost no ink left for best results.

[Mike]

BUMP

[Vic20-Ian]

I have a nice Star Lc10 colour but no colour ribbon or parallel interface yet