The IO level of SDIO pins can be changed even when they are configured as GPIOs. Voltage selection for SD2 bank is facilitated through SD_VSEL pin.
Note: IO level of SDIO pins changes to 1.8V if the status of SD_VSEL pin is high and 3.3V when SD_VSEL pin is low.
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Please find the detailed G50M product information in the below link,