40.8.4 Device Frame Number

Name: FNUM
Offset: 0x10
Reset: 0x0000
Property: Read only

Bit 15141312111098 
 FNCERR FNUM[10:5] 
Access R/WR/WR/WR/WR/WR/WR/W 
Reset 0000000 
Bit 76543210 
 FNUM[4:0]    
Access R/WR/WR/WR/WR/W 
Reset 00000 

Bit 15 – FNCERR Frame Number CRC Error

This bit is cleared upon receiving a USB reset.

This bit is set when a corrupted frame number (or micro-frame number) is received.

This bit and the SOF (or MSOF) interrupt bit are updated at the same time.

Bits 13:3 – FNUM[10:0] Frame Number

These bits are cleared upon receiving a USB reset.

These bits are updated with the frame number information as provided from the last SOF packet even if a corrupted SOF is received.