SMSC USB2524 User Manual

USB MultiSwitch

TM 

Hub

SMSC USB2524

39

Revision 1.91 (08-22-07)

 

7:3

Reserved

Reserved. {Note: Software must never write a ‘1’ to these bits}

2

INTF_PW_DN

SMBus Interface Power Down

0 = Interface is active
1 = Interface power down after ACK has completed.

{Note: This bit is write once and is only cleared by assertion of the external 
RESET_N pin.}

1

RESET

Reset the SMBus Interface and internal memory back to RESET_N assertion 
default settings. {Note: During this reset, this bit is automatically cleared to its 
default value of 0.}

0 = Normal Run/Idle State.
1 = Force a reset of the registers to their default state.

If the USB_ATTCH bit is set, then this bit will only reset the non write-protected 
registers!

0

USB_ATTACH

USB Attach (and write protect).

0 = SMBus slave interface is active.
1 = Hub will signal a USB attach event to an upstream device, and the internal 
memory (address range 00h-F0h) is “write-protected” to prevent unintentional 
data corruption.}

{Note 1: This bit is write once and is only cleared by assertion of the external 
RESET_N pin.}

{Note 2: If the SMBus interface is kept active after this bit is set, the 
PORT_ASSIGN_12, PORT_ASSIGN_34 PORT_ASSIGN_56, 
PORT_ASSIGN_7 and PORT_LOCKOUT registers may be continuously 
written to reconfigure port ownership.