Datasheet

324

32133D–11/2011

UC3D

19.7.2.9 Device Frame Number Register

Access Type: Read-Only

Offset: 0x0020

Reset Value: 0x00000000

• FNCERR: Frame Number CRC Error

This bit is cleared upon receiving a USB reset.

This bit is set when a corrupted frame number is received. This bit and the SOF interrupt bit are updated at the same time.

• FNUM: Frame Number

This field is cleared upon receiving a USB reset.

This field contains the 11-bit frame number information, as provided from the last SOF packet.

FNUM is updated even if a corrupted SOF is received.

31 30 29 28 27 26 25 24

--------

23 22 21 20 19 18 17 16

--------

15 14 13 12 11 10 9 8

FNCERR - FNUM[10:5]

76543210

FNUM[4:0] - - -