ChanServ changed the topic of ##yamahasynths to: Channel dedicated to questions and discussion of Yamaha FM Synthesizer internals and corresponding REing. Discussion of synthesis methods similar to the Yamaha line of chips, Sound Blasters + clones, PCM chips like RF5C68, and CD theory of operation are also on-topic. Channel logs: https://freenode.irclog.whitequark.org/~h~yamahasynths
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<protosphere>
re: the drive lights, flashing means it is looking for a disk, solid should mean that a disk is loaded in the corresponding drive
<protosphere>
flashing with soft power off definitely seems wrong
<protosphere>
er, rather, the lights without a button are basically activity lights, the lights with the button indicate whether a disk is loaded
<protosphere>
iirc neither should be lit in the soft poweroff state
<protosphere>
If there’s not a disk in on boot you won’t hear the seek, that’s normal
<andlabs>
well there is a disk, which I didn't notice untilw e took the computer apart
<protosphere>
The force eject will only function if it thinks there’s a disk in the drive, so that might be why that isn’t working anymore
<andlabs>
and I can't eject it so I don't know what it is =P
<andlabs>
hm
<andlabs>
maybe I"m not applying enough force?
<protosphere>
eject light should be solid in that case with soft power on
<andlabs>
someone in another server asked for higher res photos of the PSU board so I'll post those later
<protosphere>
It should be easy to press
<protosphere>
With no disk, the light without a button should flash green on boot
<protosphere>
otherwise it should be solid red as its reading the disk
<protosphere>
you have to hold the force eject for a good few seconds for it to actually fully eject; after doing so, if you put the disk back in the machine while it’s off it won’t eject again
<protosphere>
it needs to load the drive heads or whatever first before it will eject again
<protosphere>
but in that case you should be able to carefully pull the disk out of the drive
<protosphere>
if not then there’s something else wrong
<andlabs>
yeah let me try that now
<andlabs>
yeah no it's definitely being held in place
<andlabs>
there's lots of resistance
<andlabs>
but good to know, thanks
<protosphere>
the disk is definitely loaded then
<protosphere>
you have to get it to fully power on before you could remove it then
<protosphere>
(unless it somehow jammed)
<protosphere>
Does your power LED work at all?
<andlabs>
yeah but I don't remember what it was
<andlabs>
we'll continue doing everything some other time; I'm not in a position to right now
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<cr1901_modern>
Foone: While it's on my mind... channel suggestion for your autojoin list: #domesday86
<cr1901_modern>
Pretty sure you wanted one of those
<Foone>
hehe
<Foone>
I put together, uh, 35 of them?
<cr1901_modern>
Oh I thought you didn't have one/wanted one
<Foone>
that was the case. then I got overly involved in fixing that, and after assembling 35 of them, I definitely have one
<balrog>
cr1901_modern: most of the activity is on discord; if you're on discord there's no need to be on IRC :)
<cr1901_modern>
I'm not on discord lol
<sorear>
why is domesday86 making new hardware that will just break again in 10 years instead of archiving the contnet
<cr1901_modern>
The point is to archive the content
<cr1901_modern>
it taps into the raw laserdisc signal, captures it, and then digitizes it to preserve discs from the BBC Domesday project
<Foone>
the domesday86 project designed new hardware to archive the content, they then made that design available to others since it's also useful for any laserdisc (or VHS, or CED) archival
<sorear>
the website has instructions for building hardware on it but I couldn't find a download link for anything they archived
<cr1901_modern>
Oh hmmm, I didn't think to dig that deep into the LD parts. But I have seen their efforts at CD archival, so I don't think it's vaporware.
<ZrX-NoMs>
URL for the CD part?
<cr1901_modern>
If I remembered where it was I would've posted it :P
<cr1901_modern>
If I get a new link I'll post it
<ZrX-NoMs>
Been thinking about looking into raw CD someday.
<cr1901_modern>
FOSS CD controller core would be interesting (if almost completely impossible to use)
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<HXLNT_>
Realized I don't have the right tool to open Loopy cartridges, but I did dig up this photo someone took of the inside of Little Romance
<HXLNT_>
I haven't dug up too much info on the mechanisms by which PCM works on other consoles
<HXLNT_>
But I was thinking about how Casio might do this in their PCM keyboards. I wonder if that little Ricoh I/O chip just handles grabbing samples, and they're all on a ROM chip somewhere in the console or cart.
<HXLNT_>
Console seems like it would make more sense, though IDK where that would be on the Loopy PCB, since nothing is jumping out to me as looking like dedicated ROM.
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<andlabs>
uhhh
<andlabs>
yes
<andlabs>
wat
<andlabs>
ah
<andlabs>
the two big NEC chips are
<andlabs>
D23C16000 is is a 16Mbit mask ROM
<andlabs>
D23C8000 is an 8Mbit mask ROM
<HXLNT>
oh yeah, sorry i meant i didn't see any obvious ram on the console
<HXLNT>
the cartridge, yes :)
<HXLNT>
ROM
<HXLNT>
not ram
<HXLNT>
god
<HXLNT>
i was curious whether all the samples might just live on a rom chip somewhere, but if the samples are shared, seems cheaper to do it on the console than on the carts? idk.
<HXLNT>
i haven't found that much info about how other consoles do pcm
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<Lord_Nightmare>
HXLNT: you wanted something?
<HXLNT>
Not sure how much of the previous convo you saw, but I think someone mentioned you might have some ideas about IDing audio HW on the Casio Loopy.
<HXLNT>
There isn't a readily-identifiable off-the-shelf sound chip on the motherboard, and the console hasn't been emulated.
<HXLNT>
It would be cool to extract the samples if it is PCM as I'm starting to think it might be, but I'm a bit new to hardware that's got more than 8 bits to its name. ;-)
<HXLNT>
So mostly just looking for ideas and thoughts from Smart People Like Yourselves.
<Lord_Nightmare>
my guess is the audio is handled by the currently undumped/unemulated main mcu
<Lord_Nightmare>
but i could be wrong
<Lord_Nightmare>
i.e. dma-driven or software driven dac
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<ValleyBell>
HXLNT: You could try to load one of the ROMs in Audacity and play with the import parameters.
<ValleyBell>
I mean one of the already dumped cart-ROMs.
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<HXLNT>
Lord_Nightmare: There's a DAC on the board next to what I'm guessing is a Ricoh I/O chip that they put Casio's name on.
<HXLNT>
ValleyBell: Yeah, I was playing with that yesterday. Haven't found anything promising, though I don't think I've tried every permutation of all the parameters just yet.
<HXLNT>
I wasn't sure if other PCM-based consoles have the samples in the ROMs or a shared set on the console itself. But I was saying a bit ago that there isn't anything on the console itself that obviously looks like dedicated RAM.
<HXLNT>
Sorry, ROM.
<Lord_Nightmare>
hmm. i'd try straight 8 bit pcm, and oki 4-bit adpcm
<Lord_Nightmare>
its also possible it uses a sony/cd-xa style block adpcm
<HXLNT>
Cool--I'll give that a try later today.
<HXLNT>
Could I possibly be hitting up against compression as well?
<HXLNT>
I heard something in a ROM that sorta kinda sounded like the console startup sound, but it was in one ROM and not the other, so :-\
<HXLNT>
A lot of ear-squinting was done, haha
<Lord_Nightmare>
which ROM is this? what crc32?
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<cr1901_modern>
>Could I possibly be hitting up against compression as well
<cr1901_modern>
Shit, I didn't think of that. My assumption is that the mystery Ricoh chip used uncompressed 8-bit samples
<HXLNT>
Lord_Nightmare: The ROM where I thought I heard something (albeit, really a stretch) was Little Romance
<HXLNT>
I pulled the sample out, lemme throw it on a share...
<cr1901_modern>
HXLNT: Just out of morbid curiosity, do you have the whole rom? I'm curious what the rest sounds like (probably noise)
<cr1901_modern>
Also, if this is indeed a Ricoh PCM chip, chances are the value "0xFF" is illegal in the sample- the chip uses that to know when the sample ends
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<HXLNT>
You can grab a set from archive.org
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<cr1901_modern>
Excellent, thanks
<HXLNT>
cr1901_modern: But there's also the possibility that the Ricoh chip isn't PCM-specific but just a generic I/O handler, right?
<HXLNT>
I mean, based on "weird 64-pin package with two cut pins from that thing I found on ebay"
<cr1901_modern>
Yes it's possible.
<cr1901_modern>
I do wonder if both 1. The DAC connects to that mystery chip, 2. The chip is a port expander, can both be true
<HXLNT>
That's my guess
<cr1901_modern>
multimeter time :D?
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<HXLNT>
it's always multimeter time (tm)
<cr1901_modern>
Haha indeed. I'm afraid I'm out of useful feedback for now tho :(