L-USS820FD-DB AGERE [Agere Systems], L-USS820FD-DB Datasheet - Page 37

• Manufacturer Part Number: L-USS820FD-DB
• Description: USB Device Controller
• Manufacturer: AGERE [Agere Systems]

Data Sheet, Rev. 1
August 2004
Agere Systems Inc.
Register Interface
Table 34. Suspend Power-Off Locking Register (LOCK)—Address: 19H; Default: 0000 0001B
This register contains the control and status which enables the USS-820FD locking mechanism. This feature
protects the internal register set from being corrupted during and immediately after a suspend where the external
controller is powered off. The feature is enabled by the SUSPLOE bit, and its proper usage is documented in the
Special Action Required by USS-820/USS-825 After Suspend Application Note (AP97-058CMPR-04).
Table 35. Pend Hardware Status Update Register (PEND)—Address: 1AH; Default: 0000 0000B
This register contains the PEND bit.
Table 36. Scratch Firmware Information Register (SCRATCH)—Address: 1BH; Default: 0000 0000B
This register contains a 7-bit scratch field that can be used by firmware to save and restore information. One
possible use would be to save the device’s USB state (e.g., DEFAULT, ADDRESSED) during suspend power off.
The register also contains the resume interrupt enable bit.
IE_RESUME
Bit
7:1
Bit
7:1
Bit
6:0
0
0
7
Bit 7
Bit 7
Bit 7
R/W
UNLOCKED Locking Control/Status. Use of this bit is described in the Special Action Required by
IE_RESUME Enable Resume Interrupt. When set, the RESUME interrupt is enabled.
SCRATCH
Symbol
Symbol
Symbol
PEND
—
—
Bit 6
Bit 6
Bit 6
Reserved.
Pend. When set, this bit modifies the behavior of other shared register bits. See the
Special Firmware Action for Shared Register Bits section of this document for a detailed
explanation.
(continued)
Reserved.
USS-820/USS-825 After Suspend Application Note (AP97-058CMPR-04).
Scratch Information.
Bit 5
Bit 5
Bit 5
Bit 4
Bit 4
Bit 4
—
—
—
—
Function/Description
Function/Description
Function/Description
SCRATCH
Bit 3
Bit 3
Bit 3
R/W
Bit 2
Bit 2
Bit 2
USB Device Controller
Bit 1
Bit 1
Bit 1
USS-820FD
UNLOCKED
PEND
Bit 0
R/W
Bit 0
Bit 0
R/W
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