Hello,
I was looking at a similar issue recently.
The problem is that bluetooth dongles are SLAVE devices -- or in the USB terminology, simply USB devices. They are supposed to work under the control of a USB host (controller), which is ussualy a PC. The USB host has to perform USB bus enumeration and probably other complex tasks. This means your FPGA has to perform the tasks of a USB host ... (see USB Complete 3rd edition, Jan Axelson) Also note that the bluetooth dongle is supposed to be powered-up by the power lines (5V) available on the USB interface ...
Finally, the bluetooth protocol is quite complex and implementing the bluetooth stack is not trivial. You may want to take a look at
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to get an idea.
There are USB controllers that implement the OTG (On The Go) supplement to USB. They allow devices to comunicate with other devices -- that is, allow devices to work as hosts. (see
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Check the datasheets for Philips ISP1362, TransDimension TD242LP, Cypress CY7C67200EZ-OTG
My advice to you is to use a eb100-SER
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module. It has the full bluetooth stack implemented in firmware with a serial profile available on power-up and they say 230kb/s bandwidth. You connect to this module over a serial UART (easy to implement in an FPGA). It's simple to use and it worked for me ...
:) According to me you face a nice project but a huge one most probably...
Good luck and hope this helps. Cristian