├── README.md
├── cart.s
├── compile.bat
└── rom.chr


/README.md:
--------------------------------------------------------------------------------
 1 | # NESGuide
 2 | 
 3 | This repository is related to the [video](https://www.youtube.com/watch?v=V5uWqdK92i0), a tutorial for how to program the Nintendo Entertainment System (NES) and the Family Computer (Famicom). The final assembly file is given as an example of what a basic starter program should look like.
 4 | 
 5 | To compile this program, please download [CC65](https://github.com/cc65/cc65)
 6 | 
 7 | Then run the following commands:
 8 | ```
 9 | C:\PathTo\cc65\bin\ca65 C:\PathTo\cart.s -o C:\PathTo\cart.o -t nes
10 | C:\PathTo\cc65\bin\ld65 C:\PathTo\cart.o -o C:\PathTo\cart.nes -t nes
11 | ```
12 | 
13 | Where **C:\PathTo** is the path to where your cc65 folder is located and then for the files, to wherever your cart.s file is located at. The output (**-o**) of the object and NES files can be changed to whatever destination is desired. 
14 | 
15 | The result will be a .NES file located at C:\PathTo\cart.nes which can then be run using an NES Emulator. 
16 | 


--------------------------------------------------------------------------------
/cart.s:
--------------------------------------------------------------------------------
  1 | .segment "HEADER"
  2 | 	.byte "NES"		;identification string
  3 | 	.byte $1A
  4 | 	.byte $02		;amount of PRG ROM in 16K units
  5 | 	.byte $01		;amount of CHR ROM in 8K units
  6 | 	.byte $00		;mapper and mirroing
  7 | 	.byte $00, $00, $00, $00
  8 | 	.byte $00, $00, $00, $00, $00
  9 | .segment "ZEROPAGE"
 10 | VAR:	.RES 1	;reserves 1 byte of memory for a variable named VAR
 11 | .segment "STARTUP"
 12 | 
 13 | RESET:
 14 | 	SEI 		;disables interupts
 15 | 	CLD			;turn off decimal mode
 16 | 	
 17 | 	LDX #%1000000	;disable sound IRQ
 18 | 	STX $4017
 19 | 	LDX #$00
 20 | 	STX $4010		;disable PCM
 21 | 	
 22 | 	;initialize the stack register
 23 | 	LDX #$FF
 24 | 	TXS 		;transfer x to the stack
 25 | 	
 26 | 	; Clear PPU registers
 27 | 	LDX #$00
 28 | 	STX $2000
 29 | 	STX $2001
 30 | 	
 31 | 	;WAIT FOR VBLANK
 32 | :
 33 | 	BIT $2002
 34 | 	BPL :-
 35 | 	
 36 | 	;CLEARING 2K MEMORY
 37 | 	TXA
 38 | CLEARMEMORY:		;$0000 - $07FF
 39 | 	STA $0000, X
 40 | 	STA $0100, X
 41 | 	STA $0300, X
 42 | 	STA $0400, X
 43 | 	STA $0500, X
 44 | 	STA $0600, X
 45 | 	STA $0700, X
 46 | 		LDA #$FF
 47 | 		STA $0200, X
 48 | 		LDA #$00
 49 | 	INX
 50 | 	CPX #$00
 51 | 	BNE CLEARMEMORY
 52 | 
 53 | 	;WAIT FOR VBLANK
 54 | :
 55 | 	BIT $2002
 56 | 	BPL :-
 57 | 	
 58 | 	;SETTING SPRITE RANGE
 59 | 	LDA #$02
 60 | 	STA $4014
 61 | 	NOP
 62 | 	
 63 | 	LDA #$3F	;$3F00
 64 | 	STA $2006
 65 | 	LDA #$00
 66 | 	STA $2006
 67 | 	
 68 | 	LDX #$00
 69 | LOADPALETTES:
 70 | 	LDA PALETTEDATA, X
 71 | 	STA $2007
 72 | 	INX
 73 | 	CPX #$20
 74 | 	BNE LOADPALETTES
 75 | 
 76 | ;LOADING SPRITES
 77 | 	LDX #$00
 78 | LOADSPRITES:
 79 | 	LDA SPRITEDATA, X
 80 | 	STA $0200, X
 81 | 	INX
 82 | 	CPX #$20	;16bytes (4 bytes per sprite, 8 sprites total)
 83 | 	BNE LOADSPRITES
 84 | 
 85 | ;LOADING BACKGROUND
 86 | 	
 87 | LOADBACKGROUND:
 88 | 	LDA $2002		;read PPU status to reset high/low latch
 89 | 	LDA #$21
 90 | 	STA $2006
 91 | 	LDA #$00
 92 | 	STA $2006
 93 | 	LDX #$00
 94 | LOADBACKGROUNDP1:
 95 | 	LDA BACKGROUNDDATA, X
 96 | 	STA $2007
 97 | 	INX
 98 | 	CPX #$00
 99 | 	BNE LOADBACKGROUNDP1
100 | LOADBACKGROUNDP2:
101 | 	LDA BACKGROUNDDATA+256, X
102 | 	STA $2007
103 | 	INX
104 | 	CPX #$00
105 | 	BNE LOADBACKGROUNDP2
106 | 
107 | ;LOAD BACKGROUND PALETTEDATA
108 | 	LDA #$23	;$23D0
109 | 	STA $2006
110 | 	LDA #$D0
111 | 	STA $2006
112 | 	LDX #$00
113 | LOADBACKGROUNDPALETTEDATA:
114 | 	LDA BACKGROUNDPALETTEDATA, X
115 | 	STA $2007
116 | 	INX
117 | 	CPX #$20
118 | 	BNE LOADBACKGROUNDPALETTEDATA
119 | 
120 | 	;RESET SCROLL
121 | 	LDA #$00
122 | 	STA $2005
123 | 	STA $2005	
124 | 	
125 | ;ENABLE INTERUPTS
126 | 	CLI
127 | 	
128 | 	LDA #%10010000
129 | 	STA $2000			;WHEN VBLANK OCCURS CALL NMI
130 | 	
131 | 	LDA #%00011110		;show sprites and background
132 | 	STA $2001
133 | 	
134 | 	INFLOOP:
135 | 		JMP INFLOOP
136 | NMI:
137 | 
138 | 	LDA #$02	;LOAD SPRITE RANGE
139 | 	STA $4014
140 | 
141 | 	RTI
142 | 
143 | PALETTEDATA:
144 | 	.byte $00, $0F, $00, $10, 	$00, $0A, $15, $01, 	$00, $29, $28, $27, 	$00, $34, $24, $14 	;background palettes
145 | 	.byte $31, $0F, $15, $30, 	$00, $0F, $11, $30, 	$00, $0F, $30, $27, 	$00, $3C, $2C, $1C 	;sprite palettes
146 | 
147 | SPRITEDATA:
148 | ;Y, SPRITE NUM, attributes, X
149 | ;76543210
150 | ;||||||||
151 | ;||||||++- Palette (4 to 7) of sprite
152 | ;|||+++--- Unimplemented
153 | ;||+------ Priority (0: in front of background; 1: behind background)
154 | ;|+------- Flip sprite horizontally
155 | ;+-------- Flip sprite vertically
156 | 
157 | 	.byte $40, $00, $00, $40
158 | 	.byte $40, $01, $00, $48
159 | 	.byte $48, $10, $00, $40
160 | 	.byte $48, $11, $00, $48
161 | 	
162 | 	;sword
163 | 	.byte $50, $08, %00000001, $80
164 | 	.byte $50, $08, %01000001, $88
165 | 	.byte $58, $18, %00000001, $80
166 | 	.byte $58, $18, %01000001, $88
167 | 
168 | 
169 | BACKGROUNDDATA:	;512 BYTES
170 | 	.byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$01,$02,$03,$04,$05,$00,$00,$00,$00,$00,$00,$00,$06,$07,$00,$00,$00,$00,$00,$00,$00,$00,$00
171 | 	.byte $00,$00,$00,$00,$00,$00,$00,$08,$09,$0a,$0b,$0b,$0b,$0c,$0d,$0e,$0f,$10,$11,$56,$13,$14,$0b,$15,$00,$00,$00,$00,$00,$00,$00,$00
172 | 	.byte $00,$00,$00,$00,$00,$00,$00,$16,$17,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$18,$19,$00,$00,$00,$00,$00,$00,$00
173 | 	.byte $00,$00,$00,$00,$00,$1a,$1b,$1c,$1d,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$1e,$06,$1f,$00,$00,$00,$00,$00
174 | 	.byte $00,$00,$20,$21,$22,$23,$18,$24,$25,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$26,$27,$28,$00,$29,$2a,$00,$00,$00,$00,$00
175 | 	.byte $00,$00,$2b,$2c,$2d,$0b,$11,$2e,$2f,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$30,$31,$32,$33,$34,$35,$00,$00,$00,$00,$00
176 | 	.byte $00,$00,$00,$00,$36,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$18,$37,$38,$39,$3a,$00,$00,$00,$00,$00,$00
177 | 	.byte $00,$00,$00,$00,$3b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$3c,$3d,$3e,$00,$00,$00,$00,$00,$00,$00,$00
178 | 	.byte $00,$00,$00,$00,$3f,$40,$0b,$0b,$0b,$41,$42,$43,$44,$0b,$0b,$45,$0b,$0b,$0b,$0b,$46,$47,$48,$00,$00,$00,$00,$00,$00,$00,$00,$00
179 | 	.byte $00,$00,$00,$00,$00,$49,$0b,$0b,$4a,$4b,$00,$4c,$4d,$0b,$4e,$4f,$50,$0b,$0b,$51,$00,$52,$53,$00,$00,$00,$00,$00,$00,$00,$00,$00
180 | 	.byte $00,$00,$00,$00,$00,$3f,$54,$55,$12,$00,$00,$00,$57,$58,$59,$00,$5a,$5b,$5c,$5d,$00,$5e,$5f,$00,$00,$00,$00,$00,$00,$00,$00,$00
181 | 	.byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$60,$61,$00,$00,$62,$63,$64,$65,$00,$66,$67,$68,$00,$00,$00,$00,$00,$00,$00,$00
182 | 	.byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$69,$00,$00,$6a,$6b,$6c,$00,$6d,$6e,$6f,$70,$00,$00,$00,$00,$00,$00,$00,$00
183 | 	.byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$71,$72,$73,$0b,$74,$75,$76,$77,$78,$00,$00,$00,$00,$00,$00
184 | 	.byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$79,$7a,$7b,$7c,$7d,$7e,$7f,$80,$81,$82,$00,$00,$00,$00,$00
185 | 	.byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$4c,$83,$84,$85,$86,$35,$87,$00,$00,$00,$00,$00,$00
186 | 
187 | BACKGROUNDPALETTEDATA:	;32 bytes
188 | 	.byte $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55
189 | 	.byte $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55
190 | 
191 | .segment "VECTORS"
192 | 	.word NMI
193 | 	.word RESET
194 | 	; specialized hardware interurpts
195 | .segment "CHARS"
196 | 	.incbin "rom.chr"


--------------------------------------------------------------------------------
/compile.bat:
--------------------------------------------------------------------------------
1 | cd D:\
2 | 
3 | cc65\bin\ca65 program\cart.s -o program\cart.o -t nes
4 | cc65\bin\ld65 program\cart.o -o program\cart.nes -t nes
5 | 
6 | cd D:\program


--------------------------------------------------------------------------------
/rom.chr:
--------------------------------------------------------------------------------
https://raw.githubusercontent.com/InkboxSoftware/NESGuide/0f093301e747904bbba1ad7b664e512cb15cf463/rom.chr


--------------------------------------------------------------------------------