Post #4250902

2026-07-30 19:27 UTC

So, let's look at the landscape of what can be bought in low pin count, high density packages (even if not literal WLCSP) to see how hard this would be to make happen. I'm expecting the MCU is going to need 3.3V IO, and the MCU-FPGA link is thus going to have to use LVCMOS33 signaling. So any parts that do not provide 3.3V capable IO cells are out. Also, I'm not a big company so I'm limiting myself to components I can actually source/buy. Anything that is only available in reels direct from the OEM is off the table.

Replies (2)

@azonenberg@ioc.exchange 2026-07-30 19:29

MCU wise, I'm looking at STM32H7s and similar high end processors. For now, only STM32 since that's what I have the most experience wise. And only density/package combos that are stocked at distributors and provide the parallel memory controller (FMC) allowing a MMIO link to the FPGA are in scope. FPGA wise, looking at Xilinx 7 series and UltraScale+ and Efinix Trion/Topaz/Titanium to start.

Open ##4250993
@helaslo@mastodon.social 2026-07-30 19:44

@azonenberg@ioc.exchange Some newer STM32s (some parts of the U5 series for sure) have multiple I/O voltage domains, similar to FPGAs They only have M33 not M55 cores, but they are plenty powerful (both ICACHE/DCACHE and pretty high 160 MHz clock) Their bigger family members seems to be the H5 series, maybe check out those too

Open ##4251380