The Micro (STM23F4xx) I'm using happens to include a SDIO peripheral that is supposed to support the 4-bit parallel bus SD Card protocol. I'm aware that the SD Association holds patents on the protocol and requires a fee for using it. I'm wondering whether this also applies to me when I'm just using the peripheral, or whether ST Micro has payed for it in order to implement it.
Also: supposed I route all signals required for 4-bit mode (for testing, experimenting, ect.), but then happen to only use SPI mode, does the fee still apply?