The interconnection between the ST WIFI module and the microcontroller is via logic level serial signals at 115200 baud. When I designed the board, I assumed that it would be easier to interact with the ST WIFI module in real time from a serial terminal while I was figuring out how to talk to the module and get it to hook up to an access point and such. To support this, I put a 6 pin x 0.100" connector that matches the FTDI serial cable pinout on the board and included jumpers to route the serial data lines to the FTDI connector or the local microcontroller. I got the WIFI module to associate and authenticate with an access point this morning. It is possible to ping the access point or a machine connected to the access point now. This makes me really happy because the WIFI module is the last subsection of the hardware that had not been checked out.

The WIFI module uses a variant of the AT command set for configuration and control. So far, it seems pretty straight forward. I think that I will write all of the configuration and SMTP code on the PC and port it to the embedded environment when it is working. Since the serial port is the primary access, this should be the simplest path.