K51 as USB Device: how to NAK a USB IN

[johnstrohm]

USB 2.0 allows a Device to NAK a USB In request if it has no data to send.  This is normal.  We were using this on code that was originally developed on a TI Stellaris processor, then ported to the K51 when TI suddenly discontinued the Stellaris line.

Reviewing the K51 Sub-Family Reference Manual, I find no reference whatsoever to forcing a NAK condition.  Reviewing the USB code, I find no reference whatsoever to NAK in Device mode.

How do I force a NAK if I have nothing to send?

[mjbcswitzerland]

Hi

An endpoint automatically NAKs when it has no data waiting to be sent (in its BD). Therefore there is nothing that needs to be done/forced.

Regards

Mark