In the CC3100 datasheet, http://www.ti.com/li...link/cc3100.pdf, it says that the chip requires an external flash memory IC for its file system storage such as service pack file, system files, configuration files, certificate files, web page files, and user files. In the Netduino 3 Wi-Fi schematic, I do not see any external flash IC connected to the CC3100 IC. How is this possible?
If I have to guess, the CC3100's file sytem is probably stored in one of the 2 flash banks of the STM32F427. If that is true, then there must be a software layer running on the STM32F427 emulating an external flash IC supporting the required commands. But that's just a guess, can't really tell unless the firmware source code is revealed.
You can read about the external memory requirements on pages 29 - 30 in the datasheet.
Another question, is the STM32F427 talking to the CC3100 through SPI or UART? In the datasheet, it mentions that SPI can achieve up to 20MHz data transfer speed when UART can only do 3Mbps baud rate max. Giving the fact that the CC3100 can achieve a TCP throughput of up to 13Mbps and UDP up to 16Mbps, it would only make sense to use SPI over UART. In the schematic, I see both SPI host and UART host connected from the CC3100 to the STM32F427. So not sure which interface is really being used unless the firmware source code is revealed.