Software Support > GroovyMAME
SCART CRT TV And GroovyMAME Thread 2
Calamity:
--- Quote from: lettuce on January 30, 2012, 04:33:03 pm ---Yeah i had to apply a bit of vertical centering
--- End quote ---
I just hope once you find your values you just need to adjust v stretch and everything is automatically centered.
--- Quote from: lettuce on January 30, 2012, 04:33:03 pm ---Ok, if i lower the V back porch anymore than the 16 its already on, i lose the white border going around the edge of the active raster :(.
--- End quote ---
Well, that's fine, so 16 lines is your value.
--- Quote from: lettuce on January 30, 2012, 04:33:03 pm ---Now in the process of me raising the Dotclcok, the screen scrambled and wouldnt sync, so i had to quit out and start again. If i dont touch any of the Horizontal geometry settings and leave them as default (but gives me about an inch black border either side of the picture)...
HFP 3 ch 3.934
HSP 4 ch 5.246
HBP 7 ch 9.184
Im able to get the Dotclock to 59.960 or 60.058 not sure if its best to have to lower or high side of 60hz??
But if i set the Horizontal geometry to what i had in the pic on my previous post, im only about to get the Dotclock to 59.758....
--- End quote ---
Yes, that's normal. From your first picture, H sync pulse was already 4.346. That's quite below the standard TV sync of 4.7 microseconds. As you increase the horizontal frequency by raising the dotclock, your horizontal values get somewhat reduced, so you probably reached the lower limit for your horizontal sync pulse and that's why it gets out of sync. Just increase that value by one character (ch) and you won't have issues. Forget about the horizontal centering by now, we're just looking for vertical values.
Find the highest vfreq your TV can accept at 256 lines, 60 Hz is more than good, but if you could reach 60.61 (unlikely) you will be able to run frogger and such games at their native refresh.
--- Quote ---or though the side borders seem to get slightly larger when i raise the dotclock, and noticed it took about 3 seconds for the screen to sync as i had a scrambled screen for the 3 seconds and thought that it wasnt going to sync but did.
--- End quote ---
Yes, that's normal. As you increase the horizontal frequency, the picture gets narrower. Extra lines actually come from the time saved by not drawing in those borders!
That's why in order to get the right horizontal geometry values, you'll need to use a 15.7 kHz mode, rather than this 16.4 kHz mode that we're using to find your vertical values.
Calamity:
Remind that if you get a garbled screen at some point, you can just press "2" to exit full screen, fix the value and press "2" again to return full screen.
lettuce:
Ok the highest im able to go is 60.371Hz anymore and the display doesnt sync
Calamity:
--- Quote from: lettuce on January 30, 2012, 05:05:01 pm ---Ok the highest im able to go is 60.371Hz anymore and the display doesnt sync
--- End quote ---
So the value that Hfreq has at that point is the one we need (should be around 16.5 Khz??)
We just need the horizontal values for a 15.7 kHz mode to build the monitor_specs line.
lettuce:
I have here 16.662kHz.
Any other info u need to know?
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