Nexys 3 FPGA board, communicate using USB

[fahum]

Hello,

Can some Guru help me with the starting point to communicate with spartan-6 FPGA on Nexys 3 board using USB. I need to send large amount of data using software to the FPGA , so UART solution will be really slow.

Appreciate your help

 

[shaiko]

You can't use connector J4 to communicate with the FPGA.
It's used only as a USB HID controller.

Other then that, you can use the Ethernet port, but this will require implementing (or using an IP) Ethernet MAC on the FPGA - which I think isn't a project for beginners.

J13 is connected to a USB to UART IC - I think you'll be able to communicate at about 1Mbps using this interface.

 

[fahum]

You can't use connector J4 to communicate with the FPGA.
It's used only as a USB HID controller.

Other then that, you can use the Ethernet port, but this will require implementing (or using an IP) Ethernet MAC on the FPGA - which I think isn't a project for beginners.

J13 is connected to a USB to UART IC - I think you'll be able to communicate at about 1Mbps using this interface.

Thanks Shaiko but how come 1 Mbps , isnt the maximum UART bitrate = 115 Kbps ?

 

[shaiko]

Thanks Shaiko but how come 1 Mbps , isnt the maximum UART bitrate = 115 Kbps ?

No.
UARTs can go much faster then that. The maximum speed will depend upon the capabilities of the physical layer (rise/fall time of the buffers, voltage levels, quality and length of cabling) and the accuracy of the internal clocks of the communicating devices.

For example, I implemented a custom 11bit UART on a Spartan 3 that ran at speed of 5MHz.
However, the communicating devices where on the same PCB and the I/O standard was LVCMOS 3.3V (not RS232...).