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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<cr1901_modern>
ej5: How are your MCA-capades coming along?
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<ej5>
slowly working through issues one at a time. it's a slog.
<ej5>
and my ps/2 is flaky now :(
<cr1901_modern>
"Seemed like fun at the time"
<ej5>
naw i'm actually enjoying the verilog part of things
<ej5>
it's really an excuse for me to dive back in so i can prepare for doing ICE40 stuffs
<cr1901_modern>
Ahhh, see... this would be the part where I start sensing the Cascade Of Failure
<cr1901_modern>
an ice40 MCA controller w/ level shifters would be pretty cool
<ej5>
except some on the vcf forums is already doing that
<ej5>
*someone
<cr1901_modern>
So, they aren't you :P
<ej5>
but i have a few other projects in mind
<cr1901_modern>
So?*
<cr1901_modern>
And link to thread?
<ej5>
anyway i'm also thinking about just releasing the MCA adlib design the way it is, warts and all, 82c611 and all
<ej5>
with the idea that the CPLD variant will come later.
* cr1901_modern
nods
<ej5>
i think the original card wasn't really a great design.
<cr1901_modern>
Ahhh
<cr1901_modern>
Is there a thread for ice40 MCA controller on VCF, or was it just mentioned in passing?
<ej5>
there sort of is a reference to it, it's referenced from the vogons thread.
<cr1901_modern>
A dirty little secret of ice40 is that while certainly not officially supported, it can tolerate 5V inputs for about 24 hours continuously
<ej5>
he's also using the ECP5 along with a pile of Atmel PLDs
<cr1901_modern>
>I was hoping Eric would be able to make VCF-MW this past week to chat about MCA
<cr1901_modern>
It you?
<ej5>
kinda sounds like a weird design
<ej5>
yeah me but i didn't go to vcfw
<andlabs>
can someone explain what it would mean to dump a PLA
<andlabs>
because a friend just asked me and I have no idea
<ej5>
pla=programmable logic array? if so, then it's extracting the bitstream that controls its configuration
<cr1901_modern>
I don't know whether you can, tbh
<ej5>
if it's unprotected, you absolutely can
<cr1901_modern>
TIL :)
<ej5>
if it's protected, its possible with some caveats
<ej5>
GAL devices are registered and can implement state machines, so a brute force approach is basically impossible
<ej5>
PAL devices are not registered and can be brute forced UNLESS latches are implemented using logic (which is sometimes done)
<andlabs>
and what would a dumped PLA stream look like
<cr1901_modern>
I believe _that_ would be in your PAL's datasheet
<andlabs>
acutally tell them yoruselves I guess *pokes Nicole_Express*
<ej5>
it's a string of binary values, the length of which depends on the type of device it is
<andlabs>
we both forget she is here =p
<ej5>
often it's contained in a JED file (jedec format)
<cr1901_modern>
Oh hey Nicole, what shenanigans are you getting into this time :P
<andlabs>
she proofread an article I am going to publish soon where I said something about some PLA chip not being dumped
<andlabs>
as a footnote
<Nicole_Express>
oh hey
<Nicole_Express>
yeah I was just confused I suppose; is this only modern PAL/GAL type chips or is this also relevant to older ones like you'd find in the C64
<cr1901_modern>
I don't know the answer... at the very least, PAL part numbers and pinouts haven't changed much over the years
<cr1901_modern>
I don't know how different each vendor who sold a given PAL made it to actually program/read out a part tho
* ej5
digs up c64 schematics
<andlabs>
but what about NTSC logic arrays
<cr1901_modern>
What are NTSC logic arrays?
<ej5>
ahh yeah the C64 one is an older type, the 82S100
<cr1901_modern>
"The original programmable IC", huh?
<andlabs>
in comparison to previous ASICs which had to be fabricated to spec
<andlabs>
probably
<andlabs>
not 100% sure
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<cr1901_modern>
natarii: There is a video, Idk where, of someone continuially stacking lock-on carts to see how long they can make the cartridge bus before checksum errors start happening
<natarii>
lol
<natarii>
ive seen the big towers of dozens of sonic & knuckles
<KitsuWhooa>
meanwhile I have a console that causes bus errors on its own >.>
<andlabs>
cc ValleyBell this is the driver I sent you, if you want ot take a closer look
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<ValleyBell>
andlabs: Oooh, nice! I'll have a look tomorrow.
<Lord_Nightmare>
andlabs: dumping 27c301s: you can make an adapter to dump them using two(?) wires and two 32 pin sockets stacked on top of one anotehr, with some pins from the bottom of the top socket bent sideways
<Lord_Nightmare>
given that the sprites are corrupt on the dump, i'd try to do a raw dump, its possible something in the (very wrong) ROM header is confusing the INLretro
<Lord_Nightmare>
as i thought, you just have to swap pins 24 and 2 on the socket adapter
<Lord_Nightmare>
also the 315-5341 chip (a CK2605 PLD) should be dumped, i think you might be able to dump it as a truth table
<Lord_Nightmare>
https://www.jammarcade.net/ck2605-logic-diagram/ is how a ck2605 works, its basically a very fancy enhanced PAL16V8 which has a much more dynamic way of enabling tristate vs open collector on each output pin
<Lord_Nightmare>
you can't actually replace it with a gal16v8 or similar, since those don't have the features it does
<Lord_Nightmare>
an AMD MACH pld could replace it but it would need an adapter board
<Lord_Nightmare>
to figure out what combinations do stuff on the ck2605 though you need to trace which pins are inputs and outputs on the pcb
<ValleyBell>
which also has a bug that causes SMPSPlay to freeze when trying to log a VGM.
<ValleyBell>
IDs 81 and 83..8F are just a drum loop. The drum loop sounds very similar to the one used by song $82.
<ValleyBell>
The bug: It does nested loops. But it uses the same loop index for both nesting levels, which causes an infinite loop in the SMPS preparser that analyses the drum track in order to collect DAC drum IDs.
<ValleyBell>
(I included a VGM of the fixed song.)