Current code

; =======================================================
; |                                                     |
; |     Author: Hugo van de Kuilen from Hugo4IT.com     |
; |                                                     |
; =======================================================
; Bootloader was copied from a blog, the rest was made by me

*=$0801         ; Assembled code should start at $0801
            ; (where BASIC programs start)
            ; The real program starts at $0810 = 2064
!byte $0C,$08       ; $080C - pointer to next line of BASIC code
!byte $0A,$00       ; 2-byte line number ($000A = 10)
!byte $9E       ; SYS BASIC token
!byte $20       ; [space]
!byte $32,$30,$36,$34   ; $32="2",$30="0",$36="6",$34="4"
            ; (ASCII encoded nums for dec starting addr)
!byte $00       ; End of Line
!byte $00,$00       ; This is address $080C containing
            ; 2-byte pointer to next line of BASIC code
            ; ($0000 = end of program)
*=$0810         ; Here starts the real program

; Own code starts here:

; Register addresses
r0L=$02
r0H=$03
r1L=$04
r1H=$05
r2L=$06
r2H=$07
r3L=$08
r3H=$09
r4L=$0a
r4H=$0b
r5L=$0c
r5H=$0d
r6L=$0e
r6H=$0f
r7L=$10
r7H=$11
r8L=$12
r8H=$13
r9L=$14
r9H=$15
r10L=$16
r10H=$17
r11L=$18
r11H=$19
r12L=$1a
r12H=$1b
r13L=$1c
r13H=$1d
r14L=$1e
r14H=$1f
r15L=$20
r15H=$21

; API Adresses
GRAPH_init=$FF20
GRAPH_clear=$FF23
GRAPH_set_colors=$FF29
DC_VIDEO=$9F29
jsr GRAPH_init

; Setting colors
lda #$1C
ldx #$1C
ldy #$1C
jsr GRAPH_set_colors

; Video settings bytes
lda #%01110010        ; [0]1110110 Current field (idk)
                      ; 0[111]0110 Sprites, Layer1 and Layer0 enable
                      ; 0111[0]110 Unused
                      ; 01110[1]10 Chroma disable
                      ; 011101[10] Enable NTSC mode
sta DC_VIDEO          ; Store video settings

mainloop:
  jsr GRAPH_clear

jmp mainloop