LDA $2002
  LDA #$20
  STA $2006
  LDA #$00
  STA $2006

  LDA #low(background)
  STA AddrLow		; load low bytes of background data
  LDA #high(background)
  STA AddrHigh		; load high bytes of background data

  LDX #$04              ; Loop X 4 times
  LDY #$00              ; Loop Y 256 times
LoadBackgroundsLoop:
  LDA [AddrLow],y
  STA $2007
  INY
  BNE LoadBackgroundsLoop
; Outer loop
  INC AddrHigh           ; increment high byte of address backg to next 256 byte chunk
  DEX                    ; one chunk done so X = X - 1.
  BNE LoadBackgroundsLoop   ; if X isn't zero, do again