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irq note (nw)

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mamehaze 2015-03-19 10:15:06 +00:00
parent 43f92ea260
commit e598092565
1 changed files with 11 additions and 4 deletions
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15
src/mame/audio/hng64.c
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@ -21,11 +21,18 @@ data structures look very similar between all of them
IRQ mask register on the internal interrupt controller is set to 0xd8
so levels 0,1,2,5 are unmasked
so levels 0,1,2,5 are unmasked, vectors get set during the sound CPU init code.
returning random values / triggering random interrupts eventually results in a situation
where the CPU stops writing to the sound related addresses and starts reading / masking the
serial comms register.
level 0/1 irq (fatfurwa) starts at 0xd277 (both the same vector)
serial comms related, maybe to get commands from main CPU if not done with shared ram?
level 2 irq (fatfurwa) 0xdd20
simple routine increases counter in RAM, maybe hooked to one / all of the timer irqs
level 5 irq: (fatfurwa) starts at 0xc1e1
largest irq, does things with ports 100 / 102 / 104 / 106, 10a (not 108 directly tho)
no other irqs (or the NMI) are valid.
*/