Do SDIO bus speeds need to match between two devices?

Question

I have two devices that I'd like to use together, connected via their SDIO pins. The MCU can transfer data up to 200 MB/s with a 200 MHz clock speed (HS-200). The wireless module that I want to use with the MCU can only work up to 104 MB/s with a 208 MHz clock speed (SDR104). In order to use these two devices, do I need to use a bus speed that both devices can handle, i.e. SDR104? Or could I run the MCU at 200 MHz for HS-200 even though the other module can only transfer at SDR104 rates?

For reference, this would be using the NXP RT600 MCU and 88W8987 wireless module.

Answer 1

as you said, the CPU handles 200MB/s at a clock speed of 200MHz, that is assume a 8-bits bus clocked by 200MHz. the SDIO is 4 bits data bus, therefore at 208MHz SDR, it gives 104MB/s. in order for it to work, you will need to interface 4bits data bus from CPU to SDIO at a clock speed it can accept. It is OK your CPU runs interface clock speed at 200MHz if that is the MAX it can provide. but since SDIO is only 4 bits bus, so your CPU side will have to follow that throughput. usually uC have SDIO dedicated interface, that should interface with standard SDIO device.