USB Device Driver - LPC responding to IN packets with zero-length data instead of NAKs.

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by KarlBuiter on Mon Mar 02 19:53:31 MST 2015
Got a USB Device Driver ;

I have interrupt endpoints (EP) configured as IN ( 0x83).

If I have data to send, the data is sent as part of an IN transfer -
The USB_Ctrl is set for Write Enable for the EP,  the length is set, the data is sent through the register, and made valid via SIE.
The resultant response is seen in the USB Analyzer logs... Looks good.

But when I have no data to send;
I see Zero-length data responses to the IN transfer.
There should be NAKs (if I understand this correctly).

Looking for some direction in what to look for.

This is on a LPC2468