Announcements
IMPORTANT: Cypress Developer Community is transitioning on October 20th. To learn more and be prepared for this change, check out our latest announcement.
cancel
Showing results for 
Search instead for 
Did you mean: 

USB Superspeed Peripherals

Anonymous
Not applicable
        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).   
0 Likes
4 Replies
Anonymous
Not applicable
        Sorry, newlines were gone.   
0 Likes
Anonymous
Not applicable
        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.   
0 Likes
Anonymous
Not applicable

Hi Kommy,

   

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.

   

Thanks,

   

sai krishna.

0 Likes
Anonymous
Not applicable
        Hello, Sai Krishna. Thank you for replying. I don't understand this phenomenon yet. I keep to research it. Best regards.   
0 Likes