Thomas Harte
a9d1f5d925
Pulls out address reload as something I can position independently.
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Sadly receding it by 3 did not have the effect I was hoping for, of receding Enchanted Land's first register tweaking.
2019-12-27 23:47:19 -05:00
Thomas Harte
2757e5d600
Removes untrue comment.
2019-12-27 22:51:11 -05:00
Thomas Harte
5026de9653
Rejigs the video stream to ensure shifter really is continuous.
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... and definitively to avoid potential buffer overruns. Or, at least, to have a mechanism in place definitively to avoid them. Which will be tested and debugged as necessary.
Also simplifies the colour burst and border/pixels selection logic.
2019-12-27 22:47:34 -05:00
Thomas Harte
5fa8e046d8
It's inaccurrate to call this _the_ shifter. So don't.
2019-12-27 19:03:10 -05:00
Thomas Harte
274867579b
Deploys constexpr as a stricter const.
2019-12-22 00:22:17 -05:00
Thomas Harte
e5440a4146
Hacks in a colour burst.
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With a major flaw: it's implicit. I think I need a minor rethink of various components here.
2019-12-20 23:49:38 -05:00
Thomas Harte
47508d50a7
Wires through a composite video option for the ST.
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Which is great and all, except that I've not yet inserted a colour burst. So it's monochrome.
2019-12-20 20:49:14 -05:00
Thomas Harte
ed7f171736
Moves address reload to end of vertical sync.
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I have no information as to when it should be, so this is as valid a guess as any other.
2019-12-19 22:20:43 -05:00
Thomas Harte
c00ae7ce6a
Adds a one-cycle delay on frequency changes.
2019-12-13 19:57:54 -05:00
Thomas Harte
4bcf217324
Ensures delayed loading isn't interrupted by blank, hsync.
2019-12-12 23:20:28 -05:00
Thomas Harte
f6f2b4b90f
Removes double DE edge test.
2019-12-12 22:50:35 -05:00
Thomas Harte
95b5db4d87
Tweaks timings yet further, adds a FIFO reset.
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The accuracy of this may require further research.
2019-12-11 23:22:20 -05:00
Thomas Harte
de4403e021
Corrects blank timing.
2019-12-10 22:17:57 -05:00
Thomas Harte
0a405d1c06
Introduces a latency between DE and load.
2019-12-10 21:24:15 -05:00
Thomas Harte
a7cfb840ef
Adds but presently disables a diagnostic for border elimination.
2019-12-08 22:34:42 -05:00
Thomas Harte
0408592ada
Switches to byte buffers and seeks to reduce unnecessary video flushing.
2019-12-08 20:20:13 -05:00
Thomas Harte
08a27bdec7
NTSC frame length is correct; removes TODO.
2019-12-08 11:51:12 -05:00
Thomas Harte
894066984c
Moves beginning and end of vertical sync to what I now believe is its proper place.
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At least one demo now successfully opens the top border.
2019-11-19 20:13:47 -05:00
Thomas Harte
e787c03530
Slightly shortens NTSC frame.
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Either: (i) 263 is incorrect; or (ii) my logic as to frame height is incorrect. Given that the horizontal side of things is really well documented, I'm currently guessing (i). Research to do.
2019-11-18 23:47:27 -05:00
Thomas Harte
6990abc0d3
Tweaks selected output mode when both BPP bits are set.
2019-11-18 22:56:40 -05:00
Thomas Harte
ade8df7217
Permits a delay on DE propagation back to the CPU. Plus tests.
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Currently set at 28 cycles, but I don't know.
2019-11-18 22:12:24 -05:00
Thomas Harte
1202b0a65f
Establishes a pipeline for delayed public state visibility.
2019-11-17 23:28:00 -05:00
Thomas Harte
facc0a1976
Amps up the documentation.
2019-11-17 21:28:51 -05:00
Thomas Harte
253dd84109
Corrects accidental dropping of pixel residue.
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Specific issue: the repeated (start_column != end_column) test, which can no longer be correct if start_column has been incremented in the (x_&7) test.
The visible effect was to omit pixels from the output wave, which also affected observed sync timing.
2019-11-17 18:34:13 -05:00
Thomas Harte
6a82c87320
Withdraws border optimisation temporarily; I think I may be onto an output bug here.
2019-11-12 19:33:13 -05:00
Thomas Harte
f0478225f0
Adjusts logic to reduce number of output spans.
2019-11-12 19:30:28 -05:00
Thomas Harte
ab34fad8ca
Introduces a cleaner, separated shifter.
2019-11-10 21:39:40 -05:00
Thomas Harte
77ef7dc8fc
Shuffles ST and 2600 into a common parent.
2019-11-09 15:31:41 -05:00
