Datasheet

32.8.4.4 Extended Register
Name: EXTREG
Offset: 0x08
Reset: 0xxxxxxxx
Property: NA
Bit 15 14 13 12 11 10 9 8
VARIABLE[10:4]
Access
R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0
Bit 7 6 5 4 3 2 1 0
VARIABLE[3:0] SUBPID[3:0]
Access
R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 x 0 0 0 x
Bits 14:4 – VARIABLE[10:0] Variable field send with extended token
These bits define the VARIABLE field of a received extended token. These bits are updated when the
USB has answered by an handshake token ACK to a LPM transaction. See Section 2.1.1 Protocol
Extension Token in the reference document “ENGINEERING CHANGE NOTICE, USB 2.0 Link Power
Management Addendum”.
To support the USB2.0 Link Power Management addition the VARIABLE field should be read as
described below.
VARIABLES Description
VARIABLE[3:0] bLinkState (1)
VARIABLE[7:4] BESL (2)
VARIABLE[8] bRemoteWake (1)
VARIABLE[10:9] Reserved
1. For a definition of LPM Token bRemoteWake and bLinkState fields, refer to "Table 2-3 in the
reference document ENGINEERING CHANGE NOTICE, USB 2.0 Link Power Management
Addendum".
2. For a definition of LPM Token BESL field, refer to "Table 2-3 in the reference document
ENGINEERING CHANGE NOTICE, USB 2.0 Link Power Management Addendum" and "Table X-
X1 in Errata for ECN USB 2.0 Link Power Management.
Bits 3:0 – SUBPID[3:0] SUBPID field send with extended token
These bits define the SUBPID field of a received extended token. These bits are updated when the USB
has answered by an handshake token ACK to a LPM transaction. See Section 2.1.1 Protocol Extension
Token in the reference document “ENGINEERING CHANGE NOTICE, USB 2.0 Link Power Management
Addendum”.
SAM D21 Family
USB – Universal Serial Bus
© 2018 Microchip Technology Inc.
Datasheet Complete
DS40001882D-page 854