260
8331B–AVR–03/12
Atmel AVR XMEGA AU
20.15 Register Description – Frame
20.15.1
FRAMENUML – Frame Number Low
The FRAMENUML and FRAMENUMH registers represent the 11-bit value, FRAMENUM, that
holds the frame number from the most recently received start of frame packet.
• Bit 7:0 – FRAMENUM[7:0]: Frame Number
This byte contains the eight lsb sof the frame number (FRAMENUM).
20.15.2
FRAMENUMH – Frame Number High
• Bit 7 – FRAMEERR: Frame Error
This flag is set if a CRC or bit-stuffing error was detected in the most recently received start of
frame packet.
• Bit 6:3 – 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.
• Bit 2:0 – FRAMENUM[10:8]: Frame Number
This byte contains the three msbs of the frame number (FRAMENUM).
Bit
7
6
5
4
3
2
1
0
FRAMENUM[7:0]
FRAMENUML
Read/Write
R
R
R
R
R
R
R
R
Initial Value
0
0
0
0
0
0
0
0
Bit
7
6
5
4
3
2
1
0
FRAMEERR
–
–
–
–
FRAMENUM[10:8]
FRAMENUMH
Read/Write
R
R
R
R
R
R
R
R
Initial Value
0
0
0
0
0
0
0
0
