I thought that specialized routines could be programmed to offload the main CPU. The 6502 GPU would take care of "drawing" the pixels on RAM and the DAC would take care of signal generation. While in theory everything in RAM count as "pixels", it's the generation of those pixels what makes them "text", "graphics" or "sprites". It seems once more I got lost in ideas that seems practical but not feasible. Thanks all. El 05/06/2022 a las 22:08, smf escribió: > Nobody said what speed the 6502 emulating the vic2 would be running at ;-) > > With what I suggested you still need the priority encoder from the vic2 > and the shift registers. > > For the background you might use 3 buffers (colorram, text, font/bitmap) > if you went for an entire line then they are 40 bytes each. > > I don't think it's practical, in any conceivable way. There are very > good reasons why you implement such things in hardware. > > You could do a video chip with a 6502, in a similar way to the ZX80/ZX81 > uses a Z80 (it purely used the CPU as an address sequencer). > > You would feed the 6502 instructions so that it produced an ever > increasing address, you would instead connect the data up to the ROM > address and load a shift register off the ROM data. > > Probably not a single byte NOP as that is a 2 cycle instruction, feeding > in $C9's would do it as long as you save the processor status (cpu would > run CMP #$c9 40 times). > > On 05/06/2022 20:34, Gerrit Heitsch wrote: >> On 6/5/22 21:23, smf wrote: >>> The VCS had the CPU calculate graphics and then place them into into >>> shift registers. >> >> Yes, but at a lower resolution with a faster CPU und not even a single >> line. >> >> Gerrit >> >> >Received on 2022-06-06 01:00:04
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