Data Sheet

813
Atmel | SMART SAM D21 [DATASHEET]
Atmel-42181G–SAM-D21_Datasheet–09/2015
31.8.5.4 Host Frame Number Register
Name:
FNUM
Offset: 0x10
Reset: 0x0000
Property: Write-Protected
Property:
z Bits 15:14 – Reserved
These bits are unused and reserved for future use. For compatibility with future devices, always write these bits to
zero when this register is written. These bits will always return zero when read.
z Bits 13:3 – FNUM: 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.
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).
z Bits 2:0 – Reserved
These bits are unused and reserved for future use. For compatibility with future devices, always write these bits to
zero when this register is written. These bits will always return zero when read.
Bit151413121110 9 8
FNUM[10:5]
Access R R R/W R/W R/W R/W R/W R/W
Reset00000000
Bit76543210
FNUM[4:0]
Access R/W R/W R/W R/W R/W R R R
Reset00000000