> So it seems like it's kind of like low-pin-count ISA-ish bus with direct pin connections to the cpu's pins. SPI and I2C plus some generic pins. This are the

> So it seems like it's kind of like low-pin-count ISA-ish bus with direct pin connections to the cpu's pins. SPI and I2C plus some generic pins. This are the typical interfaces used in microcontrollers. If I were to build a “bigger” versions of this, I’d avoid PCIe altogether and jump to USB 3.x directly, since it’s a much better fit.