Software Support > GroovyMAME
SCART CRT TV And GroovyMAME Thread 2
lettuce:
--- Quote from: Calamity on January 27, 2012, 05:52:44 pm ---You need to test this with a 256 lines mode, adjusting your system menu so that you compress the picture vertically to get all the lines in. Then find the lowest value for the vertical porch were you start loosing lines at the top or the picture top gets distorted. That's the value we're looking for.
--- End quote ---
Yeah i seem to be having a problem getting this to fit in the screen without overscan, any ideas on this?...im using 256x256 in Arcade_OSD??
EDIT: i seem to be struggling getting any higher values on the v front porch, v sync pluse and v back proch, if i set them any higher than
VFP 1.195
VSP 0.120
VBP 0.179
gives me a scrambled display
Calamity:
Well, I'll write a tutorial on this at some point. It's definitely not obvious if you're not used to messing with this stuff.
You get a garbled screen because the hfreq gets too high (you're adding too many lines). That value of hfreq is *very important*, post it here.
Set 256x256 resolution. You should use your service menu to shrink the picture vertically to a point where you can see *all* scanlines of the raster (active and non-active), even if the picture is chopped at the top or bottom, there needs to be a black border from the picture to the plastic frame. That's just for this test, after that you can set it back to its place. Have you achieved this already?
For this test, your vertical values should be set like this:
VFP - 1 line (always fixed)
VSP - 3 lines (always fixed)
VBP - 16 lines (this is the value you have to play with)
lettuce:
--- Quote from: Calamity on January 27, 2012, 06:55:45 pm ---You get a garbled screen because the hfreq gets too high (you're adding too many lines). That value of hfreq is *very important*, post it here.
--- End quote ---
Ok these are my settings (256x256) for Horizontal geometry......
I have entered the service menu and lower the V stretch from 40 all the way down to 15!! :o in order to get the grid to fit the screen......
So whats my next set Calamity?
Calamity:
AWESOME! I didn't think the Sony would accept 16.4 KHz, that's like having a Trinitron arcade monitor!
--- Quote from: lettuce on January 30, 2012, 02:34:51 pm ---I have entered the service menu and lower the V stretch from 40 all the way down to 15!! :o in order to get the grid to fit the screen......
--- End quote ---
Yes that's quite normal. I just wonder if you had to apply any vertical centering too.
So now, I'd try to achieve 60 Hz with that resolution.
First, try finding your lower valid vertical back porch. Start reducing that value line by line. At some point, the top of the picture will start getting distorted or compressed, or you'll see some retrace diagonals. Get the lower number of lines where this doesn't happen.
Then, unlock the vertical frequency (lock vfreq) and raise the dotclock until you get 60 Hz, in case you can't, try getting as close as possible.
lettuce:
Yeah i had to apply a bit of vertical centering
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 :(.
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....
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.
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