We need to interface 8 to 16 embedded USB 2.0 devices to an FPGA. We could just use external ULPI transceivers but am wondering what FPGAs have transceivers that are USB 2.0 compatible and if the internal USB SIE gate count is low enough to make it cost effective to wire the USB devices directly to the FPGA. (Would save lots of pins ....) Any suggestions ?

You'll probably find that it is not cost effective to use a full USB implem entation inside an FPGA, unless it comes as hard logic already in the devic e. If you use an external PHY, use something with a ULPI interface to mini mize the pin count (12 pins if I recall correctly). If you can get by with a relatively 'slow for USB 2' speeds, you might be b etter off using an external USB UART like this ucts/ICs/ from FTDI. The ones I've seen will top out at around 3 MBaud, but they are USB 2, the FPGA logic to support is trivial and you ha ve a relatively small, simple interface to the part. Kevin Jennings

FPGA Internal or external USB PHY/SIE ??

Mar 27, 2016 21 Replies

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Waldek Hebisch 10 years ago

Have you lookead at the manual at all? I have BCM2835-ARM-Peripherals.pdf which seem to be the only official documentation and it has 205 pages. This is tiny compared to other chips. For example main i.MX6 manual from FreeScale has 5739 pages and there are additional smaller manuals for i.MX6.

USB part in BCM manual tells you that they use Synopsys IP, what configuration options they use with Synopsis core and list registers that Broadcom added. In a sense Broadcom released all _their_ information, but you need to get Synopsys information from other source.

Waldek Hebisch

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rickman 10 years ago

Yes, I looked at the manual. I think I already said I didn't read the entire manual, so why do you even ask? I was only looking for info on the part I was using. I don't read 205 page manuals for fun.

Seems weird that there is open source driver code for the various parts of the chip that has no released documentation. I guess you can figure out some aspects of how the chip is being used by looking at the driver code, but anything not being used would still be unknown.

Rick

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