diff options
Diffstat (limited to 'src/mame/video/tc0480scp.c')
-rw-r--r-- | src/mame/video/tc0480scp.c | 29 |
1 files changed, 21 insertions, 8 deletions
diff --git a/src/mame/video/tc0480scp.c b/src/mame/video/tc0480scp.c index 1bc0effc66c..6bc65951944 100644 --- a/src/mame/video/tc0480scp.c +++ b/src/mame/video/tc0480scp.c @@ -1,14 +1,27 @@ /* Taito TC0480SCP --------- -Tilemap generator, has four zoomable tilemaps with 16x16 tiles. -It also has a front tilemap with 8x8 tiles which fetches gfx data -from RAM. - -BG2 and 3 are "special" layers which have row zoom and source -columnscroll. The selectable layer priority order is a function -of the need to have the "special" layers in particular priority -positions. +Tilemap generator. Manages four background tilemaps with 16x16 tiles fetched +from ROM, and one foreground text tilemap with 8x8 tiles fetched from RAM. +All four background tilemaps support zooming and rowscroll, and two of them +additionally support per-row zooming and column scroll. The five tilemaps +are mixed internally (the text tilemap is always on top, the order of the +other four is selectable) and output as 16 bits of pixel data. +The TC0480SCP uses 0x10000 bytes of RAM. It seems to be able to address +up to 0x800000 bytes of ROM (0x10000 tiles) as it has 21 address lines and +32 data lines, but no known game uses more than 0x400000 bytes. + +Inputs and outputs (based on Gunbuster schematics): +- CPU address bus (VA1-VA17) +- CPU data bus (VD0-VD15) +- CPU control lines (CS, UDS, LDS, R/W, DTACK) +- RAM address bus (RA0-RA14) +- RAM data bus (RAD0-RAD15) +- RAM control lines (RWAH, RWAL, RAOE) +- ROM address bus (CH0-CH20) +- ROM data bus (RD0-RD31) +- Pixel output (SD0-SD15) +- Clocks and video sync (HSYNC, HBLANK, VSYNC, VBLANK) Standard memory layout (four 32x32 bg tilemaps, one 64x64 fg tilemap) |