hi I am going to buy a miniPCIe to PCI adapter to interface a couple of old PCI-FPGA cards and can’t figure out if the miniPCIe interface offered by MediaTek MT7622AV SOC supports both PCI_IO and PCI_MEM cycles.
I know from direct experience that routers sometimes only support PCI_MEM (e.g. the old Ubiquiti RS / Pro), and in this case it is something that is missing at the hardware level, physically a circuit that is addressed as memory by the CPU and exposed as space IO to the PCI.
Some RISC SoCs do have it, some do have not. The RB532 is an example of MIPS SoC with a PCI_IO bridge.
CPUs like 8080 and x86 both have spaces, MEM_space and IO_space implemented, while RISC CPUs do not. The IO_space requires special instructions which are not usually implemented in RISC SoCs as the only way to access the IO_space is a memory mapped “bridge”.
It’s hard to understand from the Datasheet. Not clear to me. Please let me know. Thanks