SSD1306 start display problem

Hi,
I'm trying to use an adafruit 0.96" 128x64 OLED. using SPI
I want to draw some graphics (BIG numbers in this case 30x48 pixels each)
I don't want to draw the entire display (1024 bytes) to place my number at the center (by example) of the screen.
I would like to just send 180 bytes of my little graphic
So I try this code: (part)

Code:

zero: low dc : PAUSEUS 10 'mode command val = $20 'set mem addr mode gosub send val = 1 'mode vertical (with $20 above) gosub send val = $22 'setup page start & end addr gosub send val = 1 'start page 1 (page 0 not used) High caract = 6 bytes ... 8 possible gosub send val = 6 'end page 6 (page 7 not used) gosub send val = $21 'set colonne start & end gosub send val = 49 'would like to place at the center so at row 49 (start) gosub send val = 78 ' end gosub send high dc : PAUSEUS 10 'mode display for tab = 0 to 179 lookup tab,[$00,$00,$FF,$FF,$00,$00,$00,$F8,$FF,$FF,$0F,$00,$00,$FF,$FF,$FF,$7F,$00,_ $C0,$FF,$FF,$FF,$FF,$01,$E0,$FF,$FF,$FF,$FF,$03,$F0,$FF,$FF,$FF,$FF,$07,_ $F8,$FF,$FF,$FF,$FF,$0F,$FC,$FF,$FF,$FF,$FF,$1F,$FE,$FF,$FF,$FF,$FF,$3F,_ $FE,$7F,$00,$00,$FE,$3F,$FE,$07,$00,$00,$F0,$3F,$FF,$01,$00,$00,$C0,$7F,_ $FF,$01,$00,$00,$C0,$7F,$FF,$00,$00,$00,$80,$7F,$FF,$00,$00,$00,$80,$7F,_ $FF,$00,$00,$00,$80,$7F,$FF,$00,$00,$00,$80,$7F,$FF,$01,$00,$00,$C0,$7F,_ $FF,$01,$00,$00,$C0,$7F,$FE,$07,$00,$00,$F0,$3F,$FE,$3F,$00,$00,$FF,$3F,_ $FE,$FF,$FF,$FF,$FF,$3F,$FC,$FF,$FF,$FF,$FF,$1F,$F8,$FF,$FF,$FF,$FF,$0F,_ $F0,$FF,$FF,$FF,$FF,$07,$E0,$FF,$FF,$FF,$FF,$03,$C0,$FF,$FF,$FF,$FF,$01,_ $00,$FF,$FF,$FF,$7F,$00,$00,$F8,$FF,$FF,$0F,$00,$00,$00,$FF,$7F,$00,$00],val ' Code for char 0 gosub send ' send data pause 10 ' to see it slowly next tab return

but it doesn't start at row 49... Always at ROW 0 !

Attachment 8357

I tried to see code from others (arduino too but they use libraries so... just crazy) but I can't see what's wrong.
Any help ?
Regards