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
<andlabs>
right, that's what I suspected
<andlabs>
shrug
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<whitequark>
ej5: any idea where the 89 in 89C51 naming scheme came from?
<whitequark>
it seems to mean "integrated ROM" and my guesses are atmel or dallas originated it
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<Lord_Nightmare>
i thought it came from the same jedec standard that says '3' is mask rom, '7' is eprom, '8' is eeprom and '9' is 'page-erase eeprom' better known as flash ROM
<Lord_Nightmare>
so 89C51 uses flash for storage. i think?
<Lord_Nightmare>
i think that '4' is serial rom, but i'm not sure about that
<Lord_Nightmare>
and '1' might be ram
<Lord_Nightmare>
again, i'm not sure about that
<ej5>
i think Lord_Nightmare is right.
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<whitequark>
oh wow that was a JEDEC standard?
<whitequark>
i2c is 24 and spiflash is 25 so that seems to fit
<whitequark>
some random parallel SRAM i have here is 62
<whitequark>
so i'm guessing 4 is serial eeprom and 5 is page-erase eeprom
<Lord_Nightmare>
you mean page-erase serial eeprom
<Lord_Nightmare>
aka serial flash
<Lord_Nightmare>
while 9 is parallel flash
<Lord_Nightmare>
so really, 3 is parallel mask, 4 is serial eeprom, 5 is serial flash, 6 is parallel ?factory preprogrammed eprom? or OTPROM maybe?, 7 is parallel EPROM, 8 is parallel byte-erasable EEPROM, 9 is parallel page/bank-erasable EEPROM (AKA flash)
<Lord_Nightmare>
I suspect based on the 8155 vs 8255 vs 8355 vs 8755 that 1 is parallel RAM and 2 is parallel IO
<Lord_Nightmare>
since 8355 is io plus ROM
<Lord_Nightmare>
and 8755 is io plus EPROM
<Lord_Nightmare>
8155 is ip plus RAM
<Lord_Nightmare>
and 8255 is io only
<Lord_Nightmare>
whitequark: i'm not sure its a jedec standard or not, but i strongly suspect it is
<Lord_Nightmare>
since its pretty consistent that a '7' added to any device's name changes it into an eprom version vs a mask ROM version
<Lord_Nightmare>
mc6805 vs ms68705 etc
<Lord_Nightmare>
also the later flash based motorola/freescale mcus? mc68hc908
<Lord_Nightmare>
the mask version being mc68hc08
<whitequark>
right
<whitequark>
interesting
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<whitequark>
cr1901_modern: ispMACH 4A5 is a 5V CPLD family
<whitequark>
that's still being produced, even, and they haven't set a date they'll discontinue it at
<whitequark>
there are also gazillions of those in stock at every major distributor so i'm guessing it's a few years before we run out of those even when they do
<whitequark>
I mean, 5V devices are all gonna be old.
<whitequark>
ATF1500 is 1999
<whitequark>
it might be fun to RE the ispMACH 4A5 bitstream btw
<whitequark>
seems like something one could do in a few days
<whitequark>
the BSDL file actually describes the complete programming mechanism
<cr1901_modern>
What software does 4a5 use for pnr?
<whitequark>
AFAIK there are three. ispLEVER, OrCAD and Diamond
<whitequark>
hm, Diamond doesn't support these
<whitequark>
so it seems like ispLEVER and OrCAD?
<whitequark>
i'm not sure what is the OrCAD flow even
<whitequark>
oh I see, ispLEVER uses Synplify
<whitequark>
there's LSE too
<whitequark>
they last updated it in 2018, nice
<cr1901_modern>
LSE was the only way I ever got iCECube to finish routing something
<cr1901_modern>
Anyways I'm gonna install it just so I have it on standby
<cr1901_modern>
Oh, NOW I remember why 4A5 sounded familiar... someone built a 65816 homebrew design with an MMU (yes, a 6502 that supports virtual memory). They used a Mach 4A5 for it: https://www.pc65816.de/en/html/cplds.html