USB Enumeration

[alexz]

Hi, I am using the USBN9603 - USB controller and PIC16F877A to develop a USB device.
I receive the 'Get device descriptor request' from the host and after transmitting the first 8 byte setup packet through the Endpoit zero I receive NAK from the host. And the enumeration is obviously failed.
What can be the problem?
Thank you
_________________
Alex

[Guest]

Do you know that the host immediately after receiving the Device Descriptor issues a bus reset?

Check this link:
http://www.beyondlogic.org/usbnutshell/usb7.htm

[alexz]

[alexz]

the device descriptor is 18 bytes.
I send 1rst 8 bytes, receive reset, then get again the request, send twice the 16 bytes in chunks of 8 bytes packets with receiving the ACK between, receive anothe ACK after and when I send the last 2 bytes I get the NAK.
_________________
Alex

[alexz]

I also send a zero length packet after each 8 bytes Tx.
Why does not it acknowlege the last 2 bytes of the descriptor?
_________________
Alex