> On 2020-05-29, at 22:24, tokafondo <tokafondo_at_gmail.com> wrote: > > I will try to remember the questions I posted earlier, this time with no > 'raw' tags. > > > - What's the minimum work unit of the VASYL: the bit (pixel) or the byte > (char line)? VASYL runs on DOTCLOCK frequency but VIC limits the effective granularity to PHI0 frequency. This means the smallest unit of change is one CPU cycle wide, i.e. eight pixels. > - Can the VASYL memory replace the C64 memory so the VIC-II uses the former > instead of the later? Yes and no. The programmable sequencer (which is my favourite feature) reads non-sprite data from VASYL memory. Sprite data needs to come still from C64 memory though. > - Who's refreshing the DRAM once the beamracer is installed? VIC - just as before. > - Who's providing the system clock once the beamracer is installed? VIC (derived from mainboard clock generators) - just as before. > - Can the VASYL isolate the VIC-II from the system so the C64 can run as if > it wouldn't have a VIC-II installed? Well - it wouldn't make much sense to run the machine w/o VIC installed. For once the RAM needs refresh, for twice we still need to see things. Theoretically it would be possible but I see no use for this. > - Can the beamracer work by itself with the VIC-II with no need of the rest > of the C64? (asumming it's powered and/or clocked as needed) VASYL remains hidden on power up in order to maintain full compatibility. It needs to be first a) enabled, b) programmed, c) activated. In practice this is very easy and achieved by writing to appropriate addresses. There is currently NO power-up program in VASYL. It is initialised to remain hidden until called. You shouldn't notice any difference with and without the BeamRacer board installed. > - Can the VASYL make the VIC-II switch between different color modes in a > *single* raster line? Even 40 times :-) > - Can the VASYL make the VIC-II switch between different color modes in > alternate raster lines? Absolutely. And trigger badlines, or postpone them, etc. > - Can the VASYL be used to expand the borders so a resolution higher than > 320 or 200 can be achieved? All the "classic" VIC programming techniques still apply. You can open both side and upper/lower borders at will. Now even with a few lines of BASIC code though ;-) > and finally... > > - Could a kernel mod, or a new kernel, make the VASYL make the VIC-II work > in 400x200 resolution, by expanding for 40 pixels or 5 char columns each > side, so it would enable an 80 column mode with a custom charset of 5x8 > fonts? VASYL does not change any of the VIC characteristics, does not overclock it, nor does any other non-kosher stuff ;-) Side borders remain available only for sprites as before so that you still can have some fun placing them there, but making custom and custom-sized fonts with VASYL's sequencer allows completely new possibilities where poking single value into "screen" memory can control much larger pixelcount. Think 2x2 font where each character is controlled with one byte as normally. More questions welcome! -- SD!Received on 2020-05-30 01:58:49
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