System Information:
Main CPU: 68000
Sound CPU: 6502
SoundChip: YM3812, YM2203, OKIM6295
68000 Memory Addresses:
$000000 $05FFFF Rom
$240000 $240007 Play Field 1 Control 0 (Text layer)
$240010 $240017 Play Field 1 Control 1
$242000 $24207F Play Field 1 Column Scroll
$242400 $2427FF Play Field 1 Row Scroll
$244000 $245FFF Play Field 1 Data
$246000 $246007 Play Field 2 Control 0 (First tile layer)
$246010 $246017 Play Field 2 Control 1
$248000 $24807F Play Field 2 Column Scroll
$248400 $2487FF Play Field 2 Row Scroll
$24A000 $24A7FF Play Field 2 Data
$24C000 $24C007 Play Field 3 Control 0 (Second tile layer)
$24C010 $24C017 Play Field 3 Control 1
$24C800 $24C87F Play Field 3 Column Scroll
$24CC00 $24CFFF Play Field 3 Row Scroll
$24D000 $24D7FF Play Field 3 Data
$300000 $30001F Rotary Controller
$30C000 $30C00B Controls
$30C010 $30C01F Control Register (Priority, sound, etc.)
$310000 $3107FF Palette Ram (Red & Green bits)
$314000 $3147FF Palette Ram (Blue bits)
$FF8000 $FFBFFF Main ram
$FFC000 $FFC7FF Sprites
Sprite data: The unknown bits seem to be unused.
Byte 0:
Bit 0: Y co-ord hi bit
Bit 1,2: ?
Bit 3,4: Sprite height (1x, 2x, 4x, 8x)
Bit 5: X flip
Bit 6: Y flip
Bit 7: Only display Sprite if set
Byte 1: Y-coords
Byte 2:
Bit 0,1,2,3: Hi bits of sprite number
Bit 4,5,6,7: (Probably unused MSB's of sprite)
Byte 3: Low bits of sprite number
Byte 4:
Bit 0: X co-ords hi bit
Bit 1,2: ?
Bit 3: Sprite flash (sprite is displayed every other frame)
Bit 4,5,6,7: Color
Byte 5: X-coords
Bytes 6-7: Blank
Location $30C012, when written to, causes the sprite data to be DMA'd
from $FFC000 to ?. Must be used to display/change sprites.
Location $30C002, bit 7, indicates if the DMA is complete.
May have to be done during VBlank.
Sprite X and Y coordinates are flipped compared to the normal screen
coordinates. (ie 0, 0 is the lower right corner of the screen, and
255, 239 is the upper left corner).
Sprite Collumns are store in sequential tiles.
(ie 12 would be stored as 1324)
34
Palette data:
16 Entries per palette, 16 palettes for each plane and for sprites.
0x000 - character palettes
0x200 - sprite palettes
0x400 - tiles 1
0x600 - tiles 2
Palettes are split into two banks. Each color is 1 byte (0 - 255).
Bank1:
$GGRR (2 bytes)
Bank2:
$00BB (2 Bytes)
All sprites, tiles, and characters use 0 as a transparent color.
Tile data:
4 bit palette select, 12 bit tile select.
$PTTT P = Palette (0 - $0F) T = Tile (0 - $0FFF)
All games contain three BAC06 background generator chips, usual
(software) configuration is 2 chips of 16 * 16 tiles, 1 of 8 * 8.
VBlank:
The VBlank uses IRQ 6. Interrupt enabled by setting the SR to $2300.
Playfield control registers:
bank 0:
0:
Bit 0: set = 8*8 tiles, else 16*16 tiles
Bit 1: ?
Bit 2: set enables rowscroll
Bit 3: set enables colscroll
Bit 7: set in playfield 1 is reverse screen (set via dip-switch)
Bit 7: in other playfields unknown
2: ? (00 in bg, 03 in fg+text - maybe controls pf transparency?)
4: ? (always 00)
6: playfield shape: 00 = 4x1, 01 = 2x2, 02 = 1x4 (low 4 bits only)
bank 1:
0: horizontal scroll
2: vertical scroll
4: Style of colscroll (low 4 bits, top 4 bits do nothing)
6: Style of rowscroll (low 4 bits, top 4 bits do nothing)
Rowscroll/Colscroll styles:
0: 256 scroll registers (Robocop)
1: 128 scroll registers
2: 64 scroll registers
3: 32 scroll registers (Heavy Barrel, Midres)
4: 16 scroll registers (Bad Dudes, Sly Spy)
5: 8 scroll registers (Hippodrome)
6: 4 scroll registers (Heavy Barrel)
7: 2 scroll registers (Heavy Barrel, used on other games but registers
kept at 0)
8: 1 scroll register (ie, none)
Values above are *multiplied* by playfield shape.
Playfield priority (Bad Dudes, etc):
In the bottommost playfield, pens 8-15 can have priority over the next
playfield.
In that next playfield, pens 8-15 can have priority over sprites.
Bit 0: Playfield inversion
Bit 1: Enable playfield mixing (for palettes 8-15 only)
Bit 2: Enable playfield/sprite mixing (for palettes 8-15 only)
Playfield shape:
Play Field Control 0[6] & $0f
$00 4x1, 256 rows
$01 2x2, 512 rows
$02 1x4, 1024 rows
Scroll X - Play Field Control 1[0] (Word)
Scroll Y - Play Field Control 1[2] (Word)
Row Scroll Enable - Play Field Control 0[0] & $04 (Byte)
Control:
$30C010 Playfield & Sprite priority
$30C012 DMA flag
$30C014 6502 sound cpu
$30C016 Intel 8751 microcontroller
$30C018 Interrupt ack (VBL - IRQ 6)
$30C01A ?
$30C01E Reset Intel 8751? - not sure, all the games write here at startup
Input: ($30C000)
$01 Up
$02 Down
$04 Left
$08 Right
$10 Button 1
$20 Button 2
Start Buttons: ($30C002)
$04 Start 1
$08 Start 2
Graphics:
width = 8
height = 8
total = 2048
planes = 4
planeoffsets = 0 262144 131072 393216
xoffsets = 0 1 2 3 4 5 6 7
yoffsets = 0 8 16 24 32 40 48 56
charincrement = 64
width = 16
height = 16
total = 4096
planes = 4
planeoffsets = 1572864 0 524288 1048576
xoffsets = 128 129 130 131 132 133 134 135 0 1 2 3 4 5 6 7
yoffsets = 0 8 16 24 32 40 48 56 64 72 80 88 96 104 112 120
charincrement = 256
width = 16
height = 16
total = 1024
planes = 4
planeoffsets = 262144 786432 0 524288
xoffsets = 128 129 130 131 132 133 134 135 0 1 2 3 4 5 6 7
yoffsets = 0 8 16 24 32 40 48 56 64 72 80 88 96 104 112 120
charincrement = 256
width = 16
height = 16
total = 3072
planes = 4
planeoffsets = 1048576 3145728 0 2097152 (Possibly incorrect)
xoffsets = 128 129 130 131 132 133 134 135 0 1 2 3 4 5 6 7
yoffsets = 0 8 16 24 32 40 48 56 64 72 80 88 96 104 112 120
charincrement = 256
