7 Replies Latest reply on Mar 27, 2019 11:02 PM by KandlaguntaR_36

    CX3 boot


      Cx3 boot mode is selected by Pmode1 and Pmode2,however,It's not so convenient to set the pmode1 and pmode2

      to Float state,especially in mass product process.Now I use a DIP swith to control this two pmode pins(see the attachment),but the switch device is always two large to place on the PCB.I‘m not sure if  the CX3 device  can support the IAP(In application program),so I can upgrade the firmware by an external button.

        • 1. Re: CX3 boot



          The attachment is missed.

          Please let me know what is your default PMODE settings on your board.

          SPI or I2C or USB?

          Please share the (PMODE part) schematic.

          • 2. Re: CX3 boot

            Hello,we now use a Dip Swith to control the two PMODE pins

            and our default swith state is Pmode1=float, Pmode2=0.


            Actually,we'd like to fix the Pmode1 and Pmode2 to One state,and using an external Key to realize firmware upgrade

            • 3. Re: CX3 boot

              We have the following booting options in CX3:


              PMODE[2:0][1]         Boot From

              F11                           USB boot

              F1F                          I2C, On failure, USB boot is enabled

              1FF                          I2C only

              0F1                          SPI, On failure, USB boot is enabled


              >> our default swith state is Pmode1=float, Pmode2=0.

              Is SPI, On failure, USB boot (0F1) is default boot mode?


              Firmware Upgrade:

              Is the boards already have a valid firmware?




              • 4. Re: CX3 boot

                Yes,I mean the boards already have a valid firmware,and how to update the firmware if I fix Pmode1=float, Pmode2=0?


                • 5. Re: CX3 boot

                  Then, the device by default boots the same firmware.


                  If the default firmware loaded in the SPI flash has any way to corrupt the first sector of SPI flash via vendor commands  (like - vendor commands to write to SPI Flash), then the device will come up as boot looader after a reset. Becasue the default firmware is corrupted one; so it will fall back to USB bootloader mode. Then, you can update the new firmware.

                  • 6. Re: CX3 boot

                    I have try to pull SPI_CLK to GND ,when I plug  the usb connector to PC。And It's  recognized as  USB mode,So I think it's  a method to fall back to usb mode even I fix Pmode1=float, Pmode2=0

                    • 7. Re: CX3 boot

                      Yes, this method works as well.

                      To do this, you need to touch the hardware right?

                      If you are fine with this, please go ahead.