USB

[mrrg]

Hello

 

 

Ihave some questions I want to connect a CCD and read large amounts of data to a PC.

Can I use the existing USB and FTDI chip for this?

 

Or should I connect a separate USB PHY chip ?

 

If a PHY chip is needed would the following fit?

 

http://www.base2designs.com/DUSB-PHY.htm

 

 

[alex]

The Papilio/Pro only has RX/TX connected to the FTDI chip, as such I think your max throughput will be 2Mbps over RS232 serial. I believe there is a high speed wing design based on the FT2232H chip that connects two 8 bit buses to the FPGA allowing you to get pretty high throughput speeds, based on a suitable HDL design of course. From the FTDI web site:

• USB to parallel FIFO transfer data rate up to 10Mbyte/sec.
• Single channel synchronous FIFO mode for transfers up to 40 Mbytes/sec.

I'm not sure what state that wing is in, or if you can purchase it ready made yet. Perhaps Jack can clarify. An alternative board is the Pipistrello which already has a FT2232H onboard and connects a full parallel bus to the FPGA but that is a whole 'nother expense if all you need is just a wing.

 

EDIT: This is just my opinion but I think it's not worth the effort getting a USB PHY transceiver then having to implement the USB protocol in the FPGA when you can accomplish the same thing with a $6 chip that takes care of everything for you, has a published API on the host side and you only have to deal with simple parallel access on the FPGA end.