After doing a little web browsing, it seems that Gotek has adapted the
Artery AT32F435 MCU on their newer units.
This is a huge improvement over the STM32F107 used on these originally.
288MHz, lots of flash 384KB SRAM. Looks to be a souped-up crossbreed of
the STM32F4 and F7 MCUs.
I'll have to check pinouts to see how the Artery MCUs match the STM
varieties, but I suspect they'll be pretty close, as Artery also makes
clones of standard STM32 chips (e.g. AT32F407 vs. STM32F407). I'll be
surprised if I couldn't use my STLINK programmer on one.
This isn't unusual for the Chinese; there are several clone makers of
the STM32 series. I've run into a few that are phony-branded with the
ST logo.
But that AT32F435 in the new Gotek points to being able to do more than
simply emulate a floppy. Definitely everything including the kitchen
sink type of MCU.
--Chuck