Hi !
I post my attempt to realise rasters (you know those bars of color we used to see in Amstrad CPC demos)
For now, I had a pain to manually synchronise as I don't know yet how to read any lcd vertical sync.

To do rasters you just modify quickly one or more colors from the palette , several times before the next frame.
In my little program, in 8bpp mode I just draw 2 vertical bars, then do a raster on background color.

Here's a screenshot:


And here's the code:


Code:
.nolist
#include "ti84pce.inc"
.list
.org userMem-2
.db tExtTok,tAsm84CeCmp
.assume ADL=1
      
      di
      ld hl,$e40000
      ld de,$d40000
      ld bc,153600
      ldir

      ld ix,$d40000
      ld de,320
      ld b,240
pot:    ld (ix+40),250
      ld (ix+41),250
      ld (ix+42),250
      ld (ix+43),250
      ld (ix+120),200
      ld (ix+121),200
      ld (ix+122),200
      ld (ix+123),200

      add ix,de
      djnz pot

      ld a,$27
      ld ($e30018),a
      
      ld hl,$e30200

      ld b,200
l00p:   
      ld de,0
cont:   ld (hl),de
      xor a
      ld c,25
biig:   ld a,105

tempo:   dec a
      jr nz,tempo
      dec c
      jr nz,biig
      nop
      nop
      nop
      nop
      nop
      dec e
      jr nz,cont

      ld a,222
wtp:   dec a
      jr nz,wtp

      djnz l00p

      ld a,$2d
      ld ($e30018),a
      ret


If anyone could explain how to read lcd vertical sync, that would be great Smile

EDIT: According to jacobly : the easiest way is to check bit 3 of $e30020 and write 8 to $e30028 whenever you find it set !!!
great !! I'll try that!! thanks Wink
  
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