
W81E381D/W81E381AD
Publication Release Date: January 2002
- 16 - Revision 0.52
4.5 Individual register description
4.5.1
Register Descriptions - USB Power Control Registers (E7)
FPCON
Address: S:E7H
System Reset State: 0000 0000H
USB Reset State: 000–1000H
Function Power Control Register. Facilitates the control and status relating to power-down mode,
remote-wakeup enable, function wakeup, USB reset separation, remote wake-up control and function
resume/suspend.
7
6
5
4
3
2
1
0
FPD
FRWUPE
FWKP
FRIE
FRST
FRWU
FRSM
FSUS
Bit
Number
7
Bit
Mnemonic
FPD
Function
Function Power-down Mode Bit:
When set, activates USB power-down mode. This bit should only be set if
the FSUS bit is also set. Cleared by hardware when an interrupt or reset
occurs. Recommends to set with PCON.0 & PCON.1 together.
Function Remote Wake-up Enable Bit:
Set if the function is currently enabled to request remote wake-up. This bit
is modified through the Set/ClearFeature (DEVICE_REMOTE_WAKEUP).
When ‘0’, the function can’t initiate remote resume via either FW setting
FRWU or triggered by external signal. Note that don’t set this bit until after
the
Function
is
enumerated
SetFeature(DEVICE_REMOTE_WAKEUP).
Function Wake-up Bit:
1=wake-up. Set by hardware when wake-up events occur, asserts signal
FWKP to high. This bit is “Or”ed with FSUS and FRSM to generate the
interrupt. Cleared by firmware when servicing the function. Firmware
should prioritize FRSM over FWKP if both bits are set simultaneously.
Note: This bit is not set if FRWUPE=0 or FRSM=1 or FRWU=1.
USB Reset Disable:
When cleared by firmware, a chip reset occurs upon receiving of a USB
reset signal. This resets all USB blocks, microcontroller, and all peripherals.
When set by firmware, a USB reset signal just only reset all USB blocks,
but not reset microcontroller and all peripherals. Microcontroller can be
interrupted via the interrupt source URST that is set by the completion of a
received USB reset. Note that IEN1. EA/EFSR/EF doesn't be reset furring
USB reset signaling if this bit is set.
6
FRWUPE
and
the
host
issued
a
5
FWKP
4
URDIS