mattallen37 wrote:jdc2106 wrote:...there's always the possibility that a response comes to the module at exactly the same time as a signal is going out to the module, and to handle that, I think you would need hardware control (someone correct me if I'm wrong).
Without programming the serial handler on the Wifi module, yes, you would need HW flow control to totally eliminate collisions. Either that, or a full-duplex UART line between the NXT and the Wifi module.
Actually, I saw recently that it should be possible to re-program one of the ARM cores in the Wifi module used for the DIWIFI. Apparently it can be programmed to use UART, SPI, or I2C. That means that in theory, you could re-program it to only transmit a message upon receiving a request over RS485 (a master-slave relationship). That should totally eliminate the problem... at the cost of a new version of the DIWIFI (since the programming pins are not broken out on the current HW version).
I'm not quite sure, but I believe that the ARM core must also run a TCP/IP UDP/IP stack. It won't be an easy task to modify the firmware, unless the manufacturer actually provides the sources or binaries of that.
Also note, that the datasheet mentioned a firmware upgrade command. The firmware image will be downloaded via HTTP from a given URL.