.bank 0
.org $C000

Reset:

jsr WaitSync    ; wait for VSYNC
jsr ClearRAM    ; clear RAM
jsr WaitSync    ; wait for VSYNC (and PPU warmup)

lda #$3f        ; $3F -> A register
ldy #$00        ; $00 -> Y register
sta PPU_ADDR    ; write #HIGH byte first
sty PPU_ADDR    ; $3F00 -> PPU address