3 Replies Latest reply on Oct 3, 2018 3:20 AM by SrinathS_16

    Regarding CYUSB3035-BZXC FX3 SPI Interface

    SuWa_3337731

      Hi,

       

      As per the datasheet of CYUSB3035, this devices supports an SPI master interface as mentioned below:

       

       

       

       

      FX3S supports an SPI Master interface on the Serial Peripherals port. The maximum operation frequency is 33 MHz. The SPI controller supports four modes of SPI communication with the Start-Stop clock. This controller is a single-master controller with a single automated SSN control. It supports transaction sizes ranging from 4 bits to 32 bits.

       

      Can you please let me know how many slaves it can support over SPI interface? I am already using 2 slaves on SPI interface. Can I add 2 more SPI slaves?

       

      Thanks & Regards,

      Sunny Watts

       

       

       

       

       

        • 1. Re: Regarding CYUSB3035-BZXC FX3 SPI Interface
          SrinathS_16

          Hello Sunny Watts,

           

          In case you are using more than one SPI slave, the GPIO pins of FX3 can be used to generate the Slave Select signal. The firmware needs to be implemented to perform this. And yes, 4 SPI slaves can be used along with FX3S.

           

          Also, please mention if you are using SPI for booting or is it for data transfers only.

           

          Best regards,

          Srinath S

          • 2. Re: Regarding CYUSB3035-BZXC FX3 SPI Interface
            SuWa_3337731

            Hi,

             

            Thanks for the quick response.

             

            Currently, we are using SPI interface for data transfers only. We are having I2C or SD card as boot option.

             

            I have one more question. In future, if we plan to use SPI flash for booting purpose over the SPI interface. Then is there any restriction on no. of slaves on SPI interface in this scenario?

             

            Thanks & Regards,

            Sunny Watts

            • 3. Re: Regarding CYUSB3035-BZXC FX3 SPI Interface
              SrinathS_16

              Hello Sunny Watts,

               

              When the FX3S is using SPI boot, only the Slave Select (SSN) pin on the SPI block of FX3S will be considered as the bootloader will not be aware of the presence of multiple slave devices. Hence, only the SPI flash connected on the hardware SPI block of FX3S can be used for booting. However, after the firmware is loaded from the primary flash, other SPI flash devices can be addressed by asserting the GPIOs as Slave Select (SSN) lines.

               

              Best regards,

              Srinath S