mirror of
https://github.com/deater/dos33fsprogs.git
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95 lines
2.7 KiB
Plaintext
95 lines
2.7 KiB
Plaintext
note: pausing writes out zeros, doesn't restore previous values
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which is noticable
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doubling length of writes: still issue
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removing rasterbars: still issue
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removing volume bars: still issue
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remove time update: still issue
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remove dead code: still issue
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remove title screen: still issue
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remove all graphics calls: still issue
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remove memory shuffling in back:still issue
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remove keyboard: still issue
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remove all non-irq code: still issue
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remove all text print code still issue
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remove multi file (down to 973) still issue
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remove dos33 code still issue
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remove lz4 code still issue
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remove interrupt driven still issue!?
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play at 25Hz still issue
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50Hz,inline, no play 11,12,13 still issue
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also turn off A/B freq still issue
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also turn off noise/Aamp/Bamp still issue
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move to single output routine still issue
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always volume 12 still issue
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fix clear accidentally wr r14 still issue
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generate single tone FINE!!!
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only play first 16 notes still issue
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only change C-fine value still issue
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only write val, not address still issue
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use handshake-free porta/6522 still issue
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Look at interrupt registers on 6522
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Emulator: IFR=$C0 IER=$80, Actual: IFR=$C0,IER=$C0
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For 6552-2 it is $00/$80 on both
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Tried soldering so pin 18 (PB1) always high
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still issue
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Tried reading back value from AY-3-8910, always match.
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Channel A and B now have glitches offset by 320ms?
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Interrupt happens at 50Hz=20ms? 16 samples??!??
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NOTE: Applewin Bugs
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+ Doesn't support reading back AY-3-8910 (Always returns
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last written value?)
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+ IER doesn't show Timer1 enabled? (returns 80 rather than C0)
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Now glitch happens exactly every 640ms (32 50Hz interrupts) when playing
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pattern of 8 notes repeatedly
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Remove other cards from machine to see if power issue
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still issue
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When down to writing 4 values,
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$51,$3c,$32,$50, issue seems to often hit on
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the 51->3C transition
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Down to two values, still only hit on the 51->3c transition.
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Sometimes everytime, sometimes every Xth time.
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$51 by itself = fine
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$3c by itself = fine
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50/3c and 50/32 also have issues, but not quite the same
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(Some, audio fading instead of glitch?)
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Got new AY-3-8913 chips
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Tried looking at the timings.
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8913 timings are actually worse in some cases (especially writes)
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than 8910, though still in the low us range so we shouldn't be
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hitting it?
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The programming manual and timing diagrams hint that you can flip
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the address_latch / address ordering when writing. This does
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work on real hardware but not in any of the emulators.
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Have a new test, chiptune_smallest:
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+ No IRQ, plain busy wait at 20ms
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+ No lookups, hardcode the $51 to $3c transition
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Still shows the glitch, actually very quickly.
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Changes made to test this:
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+ Try increasing the WAIT delay from 85 to 120
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(still an issue)
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