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USB Superspeed Peripherals

Contributor II


I am using sdxc UHS-1 SD CARD,card is connected to s0 port in 4 bits data interface,I am using data3 for removal and insertion mechanism.

and also using external regulator to switch the voltage level 3.3v to 1.8v and controlling regulator using GPIO in the firmware.

s0 port supply voltage is 3.3v (vdd)regardless of s0 port IO voltage(vio2),I am changing vio2.

1)why its should be change from 3.3v to 1.8v?what will be the effect on uhs-1 card detect?

2)what will happen when i make vdd is equal to 3.3v and vio2 is equal to 3.3v?will it detect uhs-1 card?

3)what will happen when i make vdd is equal to 3.3v and vio2 is equal to 1.8v?iwill it detect uhs-1 card?

4)voltage swicthing is only necessary for maximum s0 port iterface clock(intfParams.maxFreq = CY_U3P_SIB_FREQ_104MHZ)?

or voltage swicthing should be for uhs-1 card detection?

5)voltage swicthing is not necessary for s0 port iterface clock(intfParams.maxFreq = CY_U3P_SIB_FREQ_26MHZ)??

please give me an answer

thank you

1 Solution

1. You can operate the SDXC card at 3.3V (for IOs). But it can work at maximum 52 MHz. The throughput for this will be around 20 MBps.

    Set the intfParams.lowVoltage      = CyFalse; in the firmware for this.

2. If you want to operate at 104 MHz (SDR50), you have provide the 1.8 V connection to it and also set the intfParams in the firmware accordingly.

The throughput for this will be around 45 MBps.

Refer this for the snippet:



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