See there are MicroMod carriers for: ESP32, SAMD, Artemis and upcoming RP2040 (which is excellent BTW).
How about STM32F429 or F767 or H753 or H730 or G491?
Do NOT need/want: audio, video, analog, PWM: in NOR out…
Want all via SPI and I2C for smart sensors and serial protocols:
See Horowitz and Hill 3rd Ed. Figures 15.20 through 15.22.
Just need all the serial buses:
USB, UART, SPI, (two of each if possible)
I2C, CAN, JTAG (or other bootloader serial),
and, if possible, RMII Ethernet and mini PCIe itself… although those might be unavailable in some processors.
Essentially S2S (serial to serial) high performance processor via MicroMod M.2 format in and out.
Thank you. Albert