Hello.
I always taken for granted some facts about the snes hardware, but, analyzing, i've found some errors in my perceptions... so, i have a handful of quick questions to solve it.
1º) Why the 65818 delays 8 cycles to transfer 1 Byte?... i think that the logic is writting a lenght word of 8 bits in a single cycle, but i don't know if it is fault of the WRAM, SRAM, VRAM...
2º) The next thing is correct?:
NTSC: 1364 cycles per scanline
PAL: 1455 cycles per scanline
NTSC Bytes per scanline: 1364/8= 170.5 Bytes
PAL Bytes per scanline: 1455/8= 181.8 Bytes
NTSC Bytes per frame: (1364*38)/8= 6479 Bytes or 6.32KB.
PAL(224 lines) Bytes per frame: (1455*88)/8= 16005 Bytes or 15.6KB.
PAL(239 lines) Bytes per frame: (1455*73)/8= 13276 Bytes or 12.9 KB.
3º) During the drawing of an scanline, there could be breaks in the middle during... 4 cycles?... 40 cycles?... It is due to memory latencys?
4º) The 65816 has exactly 325.996 cycles in an entire frame... Is that correct?.
5º) Abut the sprites... There are sprites of 32x16, 16x32, 16x8, and 8x16 pixels?... if the answer is "yes", Can i mix them if i choose the configuration of 32x32 and 16x16?.
6º) In order to update tiles, There are some differences between "tiles of sprites" and "tiles of layers" in terms of agility of drawing? (all the things about the OAM table may can influence something, while the tile layers could write in VRAM directly).
7º) Is theoretically possible update all the tiles you receive in a frame?. For example: I transfer 180 tiles during a frame, and at the end of that, when the frame buffer shall conform the image, all that tiles can be changed in the picture.
8º) The 4 players mode of the Street Racer... Really that mode 7 working in four "screens" doesn't have any impact to the perfomance of the PPU's?, or it can work due to an surplus of power.
I mean... There is 4 rotating layers at 60fps processed separately four times every frame?, or it doesn't works like that.
I think this is all... thanks in advance!
I always taken for granted some facts about the snes hardware, but, analyzing, i've found some errors in my perceptions... so, i have a handful of quick questions to solve it.
1º) Why the 65818 delays 8 cycles to transfer 1 Byte?... i think that the logic is writting a lenght word of 8 bits in a single cycle, but i don't know if it is fault of the WRAM, SRAM, VRAM...
2º) The next thing is correct?:
NTSC: 1364 cycles per scanline
PAL: 1455 cycles per scanline
NTSC Bytes per scanline: 1364/8= 170.5 Bytes
PAL Bytes per scanline: 1455/8= 181.8 Bytes
NTSC Bytes per frame: (1364*38)/8= 6479 Bytes or 6.32KB.
PAL(224 lines) Bytes per frame: (1455*88)/8= 16005 Bytes or 15.6KB.
PAL(239 lines) Bytes per frame: (1455*73)/8= 13276 Bytes or 12.9 KB.
3º) During the drawing of an scanline, there could be breaks in the middle during... 4 cycles?... 40 cycles?... It is due to memory latencys?
4º) The 65816 has exactly 325.996 cycles in an entire frame... Is that correct?.
5º) Abut the sprites... There are sprites of 32x16, 16x32, 16x8, and 8x16 pixels?... if the answer is "yes", Can i mix them if i choose the configuration of 32x32 and 16x16?.
6º) In order to update tiles, There are some differences between "tiles of sprites" and "tiles of layers" in terms of agility of drawing? (all the things about the OAM table may can influence something, while the tile layers could write in VRAM directly).
7º) Is theoretically possible update all the tiles you receive in a frame?. For example: I transfer 180 tiles during a frame, and at the end of that, when the frame buffer shall conform the image, all that tiles can be changed in the picture.
8º) The 4 players mode of the Street Racer... Really that mode 7 working in four "screens" doesn't have any impact to the perfomance of the PPU's?, or it can work due to an surplus of power.
I mean... There is 4 rotating layers at 60fps processed separately four times every frame?, or it doesn't works like that.
I think this is all... thanks in advance!