Video timing, calculating blanking

[kallisti5]

I am writing a video card driver. One timing parameter I have to pass is H/V Blanking interval start/end.

I have all the standard timing information but can't figure out how to get the blanking start / end pixels.Here are my current calculations, I don't think their right however (you can ignore the c code, just posting it for clarity) Horiz:
// Calculate blanking
uint16 frontPorch = displayTiming.h_sync_start - displayTiming.h_display;
uint16 backPorch = displayTiming.h_total - displayTiming.h_sync_end;

uint16 blankStart = frontPorch - OVERSCAN;
uint16 blankEnd = backPorch;

Vert:
frontPorch = displayTiming.v_sync_start - displayTiming.v_display;
backPorch = displayTiming.v_total - displayTiming.v_sync_end;

blankStart = frontPorch - OVERSCAN;
blankEnd = backPorch;Thanks!
-- Alex

 

[anorlunda]

ping @sophiecentaur

 

[sophiecentaur]

ping @sophiecentaur

I just tuned into PF.
I don’t know about digital display driving but, if it were an analogue signal you want to drive, the timings of the video signal are all in the spec.. they differ between PAL and NTSC but the spec is easy to find. At the moment , I am in bright sunlight which makes googling hard for me on my dim screen.
Try “digital display driver timing” I don’t thing any actual calculations should be necessary.