Introducing VFLI for VIC-20: 208x256 pixels in 16 colours!

Modding and Technical Issues

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Mike
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Re: Introducing VFLI for VIC-20: 208x256 pixels in 16 colours!

Post by Mike »

Some time ago I could source a Sony PVM monitor, which has BNC inputs for composite and S-Video inputs for Luma/Chroma.

My VIC-20 is also equipped with an own variant of the S-Video mod, and I needed to 'extend' my monitor cable (DIN to 4x Cinch breakout adapter + AV cable) with yet another 2x Cinch to S-Video plug adapter. Before that, and with just an additional Cinch to BNC adapter on Luma, I was stuck with a B/W picture.

Here's the new cable:

Image

And here's the backside of the monitor with the new adapter plugged in LINE A Y/C IN:

Image

Now for a quick test - here we go: Let's bring colour to life! :mrgreen:

Image

Cheers,

Michael
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freshlamb
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Re: Introducing VFLI for VIC-20: 208x256 pixels in 16 colours!

Post by freshlamb »

For TL;DR: I built a VFLI vic in 2013. Thought it was broken in 2014. After sitting in a box for some time I decided I HAD to see why my VFLI Vic wasn't working. From many of the new threads on fixing Vics it seemed like a memory problem. Long story short, I removed the piggybacked 2K chips and checked my soldering and it looked good so I firmly re-inserted them. I just tried it and it worked! It has happened since then and I just have to firmly press the chips into the sockets. But the reason I am posting is more about this:

I know Mike has said this before but it is worth repeating.
For those who are hesitant to try this mod, once it is complete, your modded Vic will still run almost all software (and hardware) regularly. The exceptions are : hardware that uses the user port. It may not be compatible if it uses port B. Aside from that you may have to poke the Start of Basic vector to go back to your 3583 byte machine (poke642,16;sys58232) for unexpanded programs. Other than that it will work exactly the same! I just loaded the 3K version of Skyhawk (by Quicksilver) and it played fine.
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Barney
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Re: Introducing VFLI for VIC-20: 208x256 pixels in 16 colours!

Post by Barney »

Hello, I am extremely interested in having this mod performed on my Vic-20. Do you or would you actually perform this mod for a fee? If so, what is the price? Thank you.
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MrSterlingBS
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Re: Introducing VFLI for VIC-20: 208x256 pixels in 16 colours!

Post by MrSterlingBS »

Hello,

Can a double buffer of two screens with 3.2 kB each be realized by expanding the internal memory from 5 kB to 8 kB with appropriate wiring?

BR
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Mike
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Re: Introducing VFLI for VIC-20: 208x256 pixels in 16 colours!

Post by Mike »

It should be clear from the specification of the hardware expansion (8 KB "VRAM" instead of only 5 KB) that this is entirely possible, has always been possible and has already been used for other means - the VFLI graphics mode already needs to switch the character base mid-screen to show the overscan bitmap.

And yes, even a setup with a standard colour display, double paged in the top, and VFLI bitmap in the bottom for the scanner - for ELITE - is entirely possible and had been pondered about by me those 14 years ago already.

As in all those years there had been no significant response by people to that project here, I once decided to devote my time to other projects. That's the entire reason I did not mention that idea here until now.

VICE allows you to switch on the VFLI mod. Go, and try out your idea for yourself.
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Re: Introducing VFLI for VIC-20: 208x256 pixels in 16 colours!

Post by pixel »

Mike wrote: Fri Jan 10, 2025 5:42 am As in all those years there had been no significant response by people to that project here, I once decided to devote my time to other projects. That's the entire reason I did not mention that idea here until now.
It's lonely at the top, isn't it? :p I've spent up to an hour on some replies just to discard them – an example in general of how being interested, even deeply, doesn't resonate with the board. "Like" buttons would do for some time but only to establish fake realities. And BAM we're off topic. That's how there's no reply. Posted anyway.
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Mike
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Re: Introducing VFLI for VIC-20: 208x256 pixels in 16 colours!

Post by Mike »

pixel wrote:I've spent up to an hour on some replies just to discard them – an example in general of how being interested, even deeply, doesn't resonate with the board.
This situation (i.e. not posting a prepared post but discarding it) can happen anytime. Sometimes that post sits in the text box, you do a preview, try to grasp it from the other's view and see the message probably won't be understood anyway, or may just not serve the intended purpose. And then you may quite as well put it in the bin, indeed.
"Like" buttons would do for some time but only to establish fake realities.
The equivalent are the views or the download counters. For this thread here, as I write this reply, these are a ridiculous high five-digit figure - only a few threads in the Hardware section have more views. By that account, at least a 3-digit figure of people with the necessary skills, given interest - and where necessary, access to an electronic workshop - must have done the VFLI mod.

It's the same with the download counters. They easily go into the 3-digit numbers even for attachments that were better regarded as jokes. Must be bots doing their job. At least here I once decided to pull the plug and move all my stuff to an own server, so there's no visible download counter here in Denial for my attachments anymore, for anyone to do any kind of 'analytics' on that.
And BAM we're off topic. That's how there's no reply. Posted anyway.
Here's your reply.

...

Not just a reply, but some concluding remarks:

In 2010 I devised the VFLI mod as side branch to the (still continuing!) project of tokra and me featuring the graphics capabilities of the VIC-20. At the time already, it was quite clear to me, that the necessary changes would hold off quite some people to do this change to the VIC-20 mainboard. Some others probably discount the mod as 'cheating'. Or they just do not want to reproduce the mod, because it's not their own idea. Whatever.

It is still the original video chip that does the job, and for me, I merely lifted some restrictions that were built into the original mainboard design just be accident. I did not only the hardware redesign, I also wrote the necessary display drivers (one for the VFLI graphics mode itself, one other to do the MAXIGRAFIK display with just 2 NMIs and essentially 0% CPU load) *and* I also wrote a PC based converter so about any image can be transferred to the VIC-20. In addition to that, lots of other examples and support programs (allowing 31231 BYTES FREE for BASIC, for example) to be found in the thread here.

The display driver of the VFLI graphics mode is open source, how the technology behind it works has been documented in the finest detail in the thread "** Stable rasters on the VIC-20".

Anyone who has the necessary skills (or help from someone with those skills) and given interest should be able to reproduce the mod. The how-to is completely documented in the first page of this thread. Anyone, who does so, is not 'left' with a purposefully changed but otherwise unusable hardware change - but nearly all VIC-20 software still runs and the capabilities of the video subsystem are much improved now, with - again! - already a good lot of examples found in this thread here - enough examples to give the interested coder all the necessary information to write own programs that utilize the VFLI mod!

Just do not expect it's now solely my job to keep people happy with regular updates to this thread. Especially not given its history.
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