.include "header.inc" .include "snes_init.asm" .include "my_custom.asm" .BANK 0 SLOT 0 .org 0 .section "Vblank" VBlank: rti .ENDS .BANK 0 SLOT 0 .ORG 0 .section "Main" .MACRO Video_Port_Control ;VRAM transfer, word-access, increment by 1 lda #%10000000 sta $2115 .ENDM ;assumes 8-bit a, 16-bit xy .MACRO Load_Block_to_VRAM ARGS SOURCE DEST SIZE Video_Port_Control ldx #DEST stx $2116 ; $2116/2117 is 2byte address for VRAM upload/download. most significant bit must be 0 lda #:SOURCE ; source bank ldx #SOURCE ; source offset ldy #SIZE stx $4302 ; store data offset into DMA control register sta $4304 ; store bank into DMA source bank sty $4305 ; store size of block lda #$01 sta $4300 ; set DMA mode (word, normal increment) lda #$18 sta $4301 ; set destination register (VRAM write register) - add value to $2100 to get destination address ; i.e. this is writing to $2118, which when written writes a byte to VRAM lda #$01 sta $420b ; and start the transfer .ENDM Start: Snes_Init Set_A_8_XY_16 Load_Palette_Color $00, $00 Load_Palette_Color $00, $00 Load_Palette_Color $00, $00 Load_Palette_Color $ff, $0a Set_Screen_Brightness %00001111 lda #%00000000 ; 8x8 for all 4 backgrounds, no priority flip, Mode: 4 colors/tile w/ 32 palettes sta $2105 ; store to screen mode register ; size (last argument) depends on color mode ; location is beginning of VRAM ; put character data at VRAM $0000, tile data at $0400 lda #$04 sta $2107 ; BG1 tile map location (upper 6 bits) lda #$00 sta $210b ; BG1 character location ($1000 word intervals - can't go over $8000 b/c size of VRAM) stz $1337 ; main screen designation lda #%00000001 sta $212c ; enable bkg 1, Load_Block_to_VRAM Tiles, $0000, (8*2*3), Load_Block_to_VRAM TileMap, $0400, 32 lda #%10000001 ; enable NMI and joypads sta $4200 mainloop: Spin_Loop $02 Reset_Palette_Offset Load_Palette_Color $00, $00 Load_Palette_Color $00, $00 Load_Palette_Color $00, $00 Load_Palette_Color $ff, $0a Spin_Loop $02 Reset_Palette_Offset Load_Palette_Color $ff, $a0 Load_Palette_Color $00, $00 Load_Palette_Color $00, $00 Load_Palette_Color $ff, $0a jmp mainloop .ENDS .BANK 1 SLOT 0 .org 0 .section "TileData" Tiles: ;blank tile .db $00, $00, $00, $00, $00, $00, $00, $00 .db $00, $00, $00, $00, $00, $00, $00, $00 ;face .db %00000000 .db %00000000 .db %11000011 .db %11000011 .db %11000011 .db %11000011 .db %00111000 .db %00111000 .db %00111000 .db %00111000 .db %10000001 .db %10000001 .db %01000010 .db %01000010 .db %00111100 .db %00111100 ; different face .db %11111111 .db %00000000 .db %11111111 .db %00000000 .db %11000011 .db %00000000 .db %00111000 .db %00111000 .db %00111000 .db %00111000 .db %10000001 .db %10000001 .db %01000010 .db %01000010 .db %00111100 .db %00111100 ; each entry in the tile map is two bytes long ; here is the format: ;High Low v: vertical flip h: horizontal flip ;vhopppcc cccccccc o: priority bit p: palette number ; c: Starting character (tile) number TileMap: .db $02, $80, $02, $00 .db $02, $80, $02, $00 .db $02, $80, $02, $00 .db $02, $80, $02, $00 .db $02, $80, $02, $00 .db $02, $80, $02, $00 .db $02, $80, $02, $00 .db $02, $80, $02, $00 TileMapEnd: .ENDS