40.12.4 Host Frame Number

Name: FNUM
Offset: 0x10
Reset: 0x0000
Property: PAC Write-Protection

Bit 15141312111098 
   FNUM[10:5] 
Access R/WR/WR/WR/WR/WR/W 
Reset 000000 
Bit 76543210 
 FNUM[4:0]    
Access R/WR/WR/WR/WR/W 
Reset 00000 

Bits 13:3 – FNUM[10:0] Frame Number

These bits contains the current SOF number.

These bits can be written by software to initialize a new frame number value. In this case, at the next SOF, the FNUM field takes its new value and the MFNUM bits are cleared.

As the FNUM register lies across two consecutive byte addresses, writing byte-wise (8-bits) to the FNUM register may produce incorrect frame number generation. It is recommended to write FNUM register word-wise (32-bits) or half-word-wise (16-bits).