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Post by tokra on Dec 1, 2022 11:52:08 GMT
Are you talking about vertical or horizontal blanking?
Vertically the picture is PAL-compliant (312 lines). The map screen is 33 displayed lines high by 8 pixels each, so 264 displayed lines. NTSC is not really possible unless you reduce the line-height to 7, but as I remember JackAsser decided not to got that route.
Horizontal blanking should be as good as it gets with double-pixel-mode.
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Post by c128old on Dec 1, 2022 20:39:08 GMT
Both Amaurote and EotB supply a signal that looks sensible PAL. For a 1084 (or monitors in general?) it appears one can deviate quite a bit before things die. TV sets are picky, it seems.
I've several TV sets available (LCD Philips, Samsung and Sony each using a different and differently picky, signal capture. And a little Mid90s CRT which is quite forgiving). These will show the VDC output better depending on the setting.
Vertically the screen is locked, but horizontally not.
The effect is an unstable "walking" of the screen position (resetting, moving, not quite jumping left and right but not in the same position all the time)
(please see my comment in the Amaurote topic. Quoting: "The settings appear quite perfect (320 lines, says z64k) In particular you find the VW/HW register ($03) = $45 (69).
The 4 is the nr of vertical sync rasterlines (default=4) and horizontal (nr char+1) set to 5 (default is 9, with slow pixel clock this must be halved and this means rounding up to 5 is a choice)
When I try with a value of $44 or $43, the display on both PAL LCD TVs is fine.")
I do not know the (official?) spec on horizontal blanking for a PAL output, I think for double-pixel mode this wasn't (Really) considered.
In general: when one uses 60Hz setups on VDC the TVs appear to accept more off-spec signals. Perhaps the NTSC setting for VDC would be fine.
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Post by tokra on Dec 2, 2022 1:05:28 GMT
VWHW reg 03 is $45 in EotB as well and regs 34 and 35 were tuned to $3f and $32 shortly before release. NTSC is not possible for automap as I already mentioned because the map is 32x32 plus a line for the name so 33 lines height by 8 pixels = 264 pixel-lines which won’t work in NTSC.
In general: If you fix it for one display device it might break on another. So the settings are as close to the standard as the VDC allows. Of course you could have adjustable registers or 7 pixel high NTSC fonts but then the game would never have been finished.
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warty
KIM-1 User
Posts: 29 
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Post by warty on Jan 2, 2023 22:29:22 GMT
So cool.
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