The EMW3162 is a Wifi module with an integrated ARM Cortex M3 processor running at 120 MHz.  Having the processor integrated into the module eliminates some of the more difficult layout requirements. Most of the potential RF problems are already taken care of by the module designers.

The clock for the SPI will be running around 30 MHz in extreme cases.  At this frequency I might have to treat the signal paths as RF and will probably need filters and shielding.

Note: RF means Radio Frequency. It is used here to denote any signals that could escape the system as radio waves and cause interference.

Device Advantages

• Integrated ARM processor with 30 Mbps SPI interface
• 5 V tolerant pins
• USB capabilities (possibly used to update firmware/or configure wifi)
• simplifies hardware design
• About US $10 each
• 1 MB Code space(should be more than enough providing WiFi Stack is not huge)
• Several different library options.

Device Disadvantages

• Share processor with WiFi stack
• Will need better understanding than stand alone wifi/bluetooth stack (This means longer learning curve)
• I am unfamiliar with STM32 processors