OV7670 settings

Other Hardware Sensors
1

Hello,
I am trying to get the OV7670 working. I would like to have RGB565 with VGA and/or QVGA resolution and lowest possible amount of pixels per second (slow PCLK). I feed the XCLK with ~11MHz.

I have some strange problems:

VGA + RGB565 [write(register, value)]:
write(0x40, 0xD0);//RGB565//00-FF
write(0x12, 0x04);//RGB

Rising VSYNC 13.67s (ok, 11 instead of 24 MHz used)
Rising HREF~510VSYNC (ok)
Between two risings of HREF ~784 PCLK (ok)

Until there everything is finel. Now I want to slow down PCLK:
write(0x40, 0xD0);//RGB565//00-FF
write(0x12, 0x04);//RGB
write(0x11, 0x9F);//CLK div 32

Rising VSYNC 0.43s (ok)
Rising HREF etwa 51013.67s (not ok! I expected 5100.43*s)
Between two risings of HREF ~784 PCLK (ok)

Datasheet mentions a PCLK divider:
write(0x3e, 0x14);//Scale enable, Div16
Nothing happened. In addition:
write(0x73, 0x0C);//Div16
Still nothing.

Any ideas?

2

I just tested the DBLV (0x6B) register to speed up the Clock speed. This works as intended.

write(0x6B,0x8A);

Result: 6 times faster HREF.

But how can I slow it down?!?!