3 Replies Latest reply on Mar 12, 2014 7:44 AM by DaKn_263916

    PSoC5LP boot detail (blank/erased flash -- what happens?)

      I have read the various application notes presented in these forums when similar questions come up. The application notes all say that the datasheet explains the boot options for the 5LP, but there is nothing in the datasheet which goes through the 5LP boot sequence. The TRM for the 5LP seems to skip over the stage I am most interested in. I understand that CSP packaged 5LP devices have a factory-installed USB bootloader, but I'm looking at the 100 pin TQFP packaged devices.


      It is my understanding that, from the factory, these devices are blank. What I do not see in any of the application notes or the datasheet is positive confirmation of the presence of a ROM bootloader in the 5LP devices. Can someone confirm the device operation when the flash is erased? Does it just halt? i.e. when the boot phase (section 20.3.2 in the TRM) completes, does the 5LP CPU simply start executing instructions from address 0 (section 20.3.3 in the TRM)? What happens if address zero is erased?


      AN61290 mentions that SWD or JTAG can be used for programming, and refers to AN60616 regarding the PSoC startup procedure. This application note, however, only details what happens with the program loaded in flash memory. AN73854 seems to indicate that a blank device will simply halt. It instead focuses on the bootloader PSoC object (which of course must be programmed in).


      To summarize, I'm looking for information about the in-system programmability of the 5LP devices in their "from the factory" state. What are my options for programming a new device?

        • 1. Re: PSoC5LP boot detail (blank/erased flash -- what happens?)

          There are few possibilities to program an empty (virgin) chip. Yes there are some rudimentary functions to program a row of flash already residing in the chip, but they (of course) cannot be erased. Look at the System Reference Guide (accessable from help-menu). These functions are used by ISSP programmers to download the data.


          The term "Bootloader" is widely used for a piece of software that you have to program yourself into the chip, some versions are already made for you. These bootloaderrs need a communication interface (USB, UART,I2C...) and an external device (PC) to communicate with. This allows for updating a PSoC in the field without the need of having the complete IDE / Programmer at the customer's site.





          • 2. Re: PSoC5LP boot detail (blank/erased flash -- what happens?)

            The way to tell what a processor will do on power up into erased program


            memory is to look at its technical reference to see what happens encountering


            an instruction of null. Goto ARM website and refer to technical manual.




            Regards, Dana.

            • 3. Re: PSoC5LP boot detail (blank/erased flash -- what happens?)

              To see if you can order factory devices programmed with boot


              loader contact local Cypress rep or sales manager, or file a case -








              To file a tech case -








              “Technical Support”


              “Create a MyCase”




              You have to be registered on cypress.com to do this.




              If Cypress does not offer this you could always go to a 3'rd party programming


              house (or ask in the case for a referral).








                        http://www.cypress.com/?rID=2543      All things PSOC programming






              Regards, Dana