2 Replies Latest reply on Mar 12, 2018 12:05 AM by gedic_2778001

    Regarding sdcard fx3s


      please see the attached schematic of fx3s raid on chip usb dongle

      in this schematic,

      why they are using SI2305DS-T1-E3E31 mosfet (U8) and GPIO  VSD1_GPIO14

      What's the purpose?


      thank you

        • 1. Re: Regarding sdcard fx3s



          That is to provide a way to turn on / off the power supply to the SD card if required. However the default firmware doesn't seem to use GPIO 14 for this purpose. But this can be included if required.



          - Madhu Sudhan

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          • 2. Re: Regarding sdcard fx3s

            Hi Madhu Lakshmipathy,

            i am interfacing sd card to fx3s,sd card type is SDXC UHS-1,

            For sdxc card detection,UHS-I SD memory card uses 3.3V signal voltage at initialization and then shifts to 1.8V. As suggested in FX3S- Schematic of USB RAID ON  CHIP USB DONGLE , we connected an external regulator and monitoring this using GPIO.

            according to AN70707,

            1)In the case of SD card, the VDD should be tied to 3.3 V regardless of the I/O voltage used on the other SD lines.

            2)SD card voltage supply (VIO2 or VIO3) should be changed to 1.8 V dynamically when UHS-I memory card is used.

            various operating frequencies supported on the storage port by the FX3S device

            * CY_U3P_SIB_FREQ_104MHZ (intfParams.maxFreq = CY_U3P_SIB_FREQ_104MHZ)



            my questions are

            1)Is there any relation between operating frequency on storage port and its io voltage??

            2)if io voltage of s port is 3.3v and suplly voltage vdd is 3.3v, storage port will detect sdxc interface??

            3)if operating frequency is 48MHz,do we need an external regulator to switch the voltage from 3.3v to 1.8v?

            4)if frequency is greater than 48MHz,do we need an external regulator?

            5)what is 48MHz will do?is it only for read from and write to sd card data speed?


            please let me know,help us

            thank you