When a NYET handshake is received by the Host for an OUT transaction in high speed (HS) mode, the Host controller erroneously decrements the Nak counter, qTD.NakCnt.
Minor. NAK responses generally occur multiple times per reload of the Nak counter. A NYET response occurs no more than once per reload.
See Details section, below.
Systems that use the USB controller in Host mode.
|Device Revision(s) Affected:||All, no plan to fix. Refer to (Xilinx Answer 47916) - Zynq-7000 SoC Silicon Revision Differences|
The Host Controller (HC) uses the Nak counter, qTD.NakCnt, and the Reload field, qTD.RL, to throttle the flow control to an endpoint. The flow control operation is described in section 4.9 of the EHCI specification. This control is used to stop the flow PING transactions that might be continually NAKd by the endpoint.