2 Replies Latest reply on Jul 15, 2015 8:42 PM by jone_yi_1844281

    SN8200 & Custom PCB

    courk

      Hi,

       

      I'm designing a custom PCB based on the SN8200.

       

      The design is heavily based on the "Discover Wifi" board schematics. Further, I'm not using the optional 32.768 KHz slow clock input. Relevant pins are grounded or left unconnected in respect to the datasheet.

       

      I am able to flash the firmware using the STM32-STLINK utility through the SWD interface. Flashing the board works perfectly, I can download and verify the code without any problems. The code seems to be running as I can halt the core and check the values of the registers. For instance, I can confirm the PC is changing.

       

      Nevertheless, even when flashed with the proper firmware, the SN8200 doesn't seem to emit any WiFi signal. For instance, by configuring a firmware using the SN8200 SNIC Monitor, making the AP enable on this firmware, and downloading this firmware, the hotspot is not created. The very same firmware on my "Discover WiFi" board is working.

       

      What kind of issue can explain this behavior? Bad wiring? Damaged SN8200? Poor power supply? (even if I've checked the 3.6V WiFi power supply and it doesn't seem to be the source of my troubles).

       

      Thanks !

       

      skerr_1713761 yfang@murata.com user_422260470 kkoyama_1725561 ghouse

        • 1. Re: SN8200 & Custom PCB
          gdepaula

          It could be several things.  It's hard to tell without looking at both schematics for the development board and your own custom board.  It definitely seems to be hardware related.  Something may have been wired up differently between the two boards.

           

          If it's firmware, maybe an external device/sensor can cause a serial port (such as I2C) to enter an infinite loop at initialization, so check any new peripheral yo may have added to the design.

           

          Have you solved this problem?

           

          Cheers,

          Gil

          • 2. Re: SN8200 & Custom PCB
            jone_yi_1844281

            Does your discovery board include the 32.768K Hz clock ?

            SDK after 3.1.2 will check and wait the 32.768KHz clock input stable!