Denial

Yet you would preferably use open-collector or open-drain outputs for that.

mmmh doesnt "NMOS" imply "open-collector"?

IIRC in NMOS there is only an active driver to GND, and a pullup to VCC (and that pullup is actually a FET).

However, multiple NMOS outputs driving the bus is a common thing to do and no problem at all - and you want to reproduce that exact behaviour for a drop in replacement of an NMOS IC.

Several bus signals cause the luma to slightly decrease - see this picture (much exaggerated for demonstration of course). In the vic20 there is probably similar stuff happening.

It would indeed be nice to get some pictures from different people... if only to confirm (or not) that the colors vary a bit between individual chips

Cool, thanks, i added them to the testrepo. Also the odd/even lines seem to be correct in VICE. The colors themselves are still a bit off here and there... *sigh*

Ah too bad.... someone else perhaps? Mine has +8k only ...

NICE! could you provide a screenshot from the real thing too? What i want to find out right now is if VICE uses the right "palettes" for odd and even lines. That can be seen with those color pairs that produce significantly different mixed color when the odd/even lines are swapped around (...

After the vic20 color measurement for odd/even lines someone did a while ago... i somehow forgot to verify we are actually using the right colors for odd and even lines. Since this is a subtle effect, another test program is needed. One of you guys (mike?) can probably knock this up much quicker tha...

I believe the $9000 and $9001 set to zero-effects are not emulated as well.

so where is the bug report with testcases?

I fell into the same trap on vic20 (on c64 the NMI line goes directly to the CPU, so no ACKing is required)

MMMh but didnt "we" verify the tests match real VIC and VICE?

I mean cpu clock (NTSC) vs cpu clock (PAL)

That will not work - The videotiming is tied to the timing of the machine. (Unless you want to implement a framebuffer in the FPGA and output video async)

Looks like a said the same before too. Memories...

this will also generate video output consisting of 512 lines per frame, so it will also confuse most (all?) monitors.

please make a test program for this!