Posted on February 15th, 2009
Been improving OSCA on the V6Z80P some more. I’ve now added a line sync’d co-processor, which like the Amiga’s Copper, runs its own program under DMA to write to the video registers at specific scan lines without using the CPU or interrupts. Also added a slightly ‘experimental’ display option to the bitmap mode, which I’ve call Flood. When this is selected, colours can be ‘smeared’ across a scanline depending on the value of the current pixel – this may be useful for automatically filled vector graphics, though it would need some careful line-drawing. Finally, I’ve improved the tilemap mode – you can now have a single bank of 2032 tiles, as the system uses 2-byte tile indexes (some of the upper bits are used to flip the tile images vertically and horizontally as well).