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Dear all, I use NRDY event callback function on USB 3.0. registered as follows. CyU3PUsbRegisterEpEvtCallback( CB_func,CYU3P_USBEP_NAK_EVT, 0x0000, 0x0008 ); // used EP3 consumer But,this NAK_EVT callback function (CB_func) is invoked more times than NRDY Transaction packet fx3 received. (I counted NRDY TP times with USB protocol analyzer and CB_func invoked times with ICE.) Is/Are there other trigger except NRDY TP invoking NAK_EVT callback? # using latest FX3 SDK (v1.2).
I found a new fact. When FX3 transmits Data Packet with EoB(End of Burst) bit '1' and NRDY Transaction Packet, NAK_EVT callback function is invoked. Is it the specification of FX3 SDK ? I thought that NAK_EVT callback is invoked by only NRDY TP on USB 3.0.
This callback is triggered whenever the device gives an interrupt notification that an EP is not ready. How many more times you are observing the call back compared to the NRDY packets that are there on the USB bus. Is there any relevance that you observed in these numbers. One possibility could be that this callback keeps happening repeatedly from the point of an NRDY response until the endpoint becomes ready.