Regarding USB interface with FPGA

[preet]

Dear all,
I want to implement USB controller on xilinx/ altera FPGA,
my question is-

1. is it possible to directly connect USB data+ and data- pin to FPGA ?
2. is there any additional interface IC needed to achieve the same?
3. please provide links for USB Controller document details

Regards

Preet

 

[dfordivam]

You cannot connect usb D+ and D- pins directly to the FPGA pins. You atleast need a simple USB peripheral controller and using this chip you can implement the USB protocol yourself on FPGA.

Checkout the following link for USB protocol implementation on FPGA
**broken link removed**

USB preipheral controller - **broken link removed**

But doing all this is a very big and tedious task. You should better look at this USB controller, which does most of the work for you. And you need to only implement the control block to get data from this chip.
Cypress EZ-USB FX2LP - EZ - USB FX2LP™ - USB host - peripheral controllers - PDAs - Set - top boxes - MP3 players / Personal Media Players - Cypress Semiconductor

 

[FvM]

There are some designs, that are implementing the USB controller function in FPGA logic, from IP vendors (e.g. System Level Solutions- Designing Through Innovation) as well as opencores.org. They are using at least external USB drivers or a full USB PHY. The latter is at least necessary for high speed USB. If you aren't required to keep the USB electrical specification exactly, e.g. for an USB interchip or similar short distance application, FPGA I/Os can drive the USB data lines directly.

Mentioning these solutions doesn't mean to suggest them, however. In many cases, an external USB controller will be a more convenient solution. FTDIchip.com should be also considered for simple interfaces.

 

[preet]

thanks for the replies,

could i use differential pin of any fpga as D+ and D-

Regards

Preet