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Debugging WiFly



I’m in the process of getting the WiFly shield to work. I’m looking at the COM<->WiFly ‘drivers’ code dated Sep 24th . The COM part (with a MAX233cpp) works OK and I can verify this some software loopback code on the Domino. The SPI part seems to initialise OK, but I’m just getting a stream of 56 apparently random chars:

AWG??77÷·Ø@ '÷7o¶Þw·@ 77¶Áç·`±·ßG·±yç¶6¶¡@ g¶ ??×0

back from the WiFly approx every 9 seconds and when the WiFly leds are showing just green without flashing yellow. Any ideas what’s going on or how to debug this further?




The WiFly shield depends on the availability of power on the power connector so remember to add the power pack.

Last time I used the driver it worked fine so I am not sure what is the cause of this behavior. The SPI<->UART is a bad idea but that was required on arduino since there is only one serial port, FEZ has plenty :slight_smile: But, you still should be able to make it work.

  1. Try to write then read from the scratch-pad register on the SPI<->UART chip.
  2. Maybe the default baud rate is not correct so check the WiFi module datasheet.


Thanks Gus,

I did add the power (I saw that in a WiFly post here :slight_smile: ). Yep, was wondering why we went through SPI to get to the UART on the WiFly board :). For the benefit of anyone else looking at this shield, the problem was the WiFly UART baud rate - the newer SparkFun boards need this:

    WriteRegister(Register.DLL, 0x60); //0x60 = 9600 with Xtal = 14.7456MHz

as the xtal is faster. Was able to get into the cmd mode and join a network etc after that. Thanks for your prompting Gus, will have to figure out SPI debugging another day :slight_smile:

Was wondering what the liklihood of getting a BlueTooth or WiFi USB dongle running on the Domino? Also the chances of making [italic]client https ssl [/italic]requests with the WiFly using the NETMF open source SSL code - seems to me I would ‘just’ need to encode and decode the traffic. Anyway thanks for your help Gus.




Great Alan, happy you got your project moving. Sine we are about done with Ethernet, the next thing is WiFi so you and our Joe (and anyone) can workout the details and make WiFi easily available to everyone.


I don’t know about Blue Tooth, but I don’t think your going to see a USB WiFi dongle on the Domino.

I believe that most USB WiFi dongles do not have a built-in IP stack. This has to be implement in the host. The Domino does not have a built-in stack.

Wireless support, on the Domino, could be implemented in a similar way to the ethernet support soon to be released. The IP stack is in the chip etthernet (W5100).

I would think GHI would implement internal support for the WiFly shield, which has a stack on the shield.


USB dongles are very cheap (under $10!) but did you ask yourself why? The reason is that they put all the work in the PC and there is minimal work on the dongle itself. This means, we have to do huge amount of work to make it work on an embedded device, FEZ or anything else. At the end, you will end up using most of your resources just to run a dongle…Basically, it is not worth the efforts.


We have a previous experience with USB Bluetooth dongles. It is hard to do but it can be done. Maybe in future products if we’ve seen a considerable interest in that.