USB MultiSwitchTM Hub

 

 

Datasheet

7.1.4.8

Register 07h: Configuration Data Byte 2 (Reset = 0x00)

 

 

 

BIT

 

 

NUMBER

BIT NAME

DESCRIPTION

 

 

 

7

DYNAMIC

Dynamic Power Enable: Controls the ability of the Hub to automatically

 

 

change from Self-Powered operation to Bus- Powered operation if the local

 

 

power source is removed or is unavailable (and from Bus-Powered to Self-

 

 

Powered if the local power source is restored). {Note: If the local power source

 

 

is available, the Hub will always switch to Self-Powered operation.}

 

 

When Dynamic Power switching is enabled, the Hub detects the availability of

 

 

a local power source by monitoring the external SELF_PWR pin. If the Hub

 

 

detects a change in power source availability, the Hub immediately

 

 

disconnects and removes power from all downstream devices and disconnects

 

 

the upstream port. The Hub will then re-attach to the upstream port as either

 

 

a Bus-Powered Hub (if local-power in unavailable) or a Self-Powered Hub (if

 

 

local power is available).

 

 

0 = No Dynamic auto-switching.

 

 

1 = Dynamic Auto-switching capable.

6

Reserved

Reserved, always = ‘0’.

5:4

OC_TIMER

OverCurrent Timer: Over Current Timer delay.

 

 

00 = 0.1ms

 

 

01 = 2ms

 

 

10 = 4ms

 

 

11 = 6ms

3

COMPOUND

Compound Device: Allows the OEM to indicate that the Hub is part of a

 

 

compound (see the USB Specification for definition) device. The applicable

 

 

port(s) must also be defined as having a “Non-Removable Device”.

 

 

Note: When configured via strapping options, declaring a port as non-

 

 

removable automatically causes the hub controller to report that it is part of a

 

 

compound device.

 

 

0 = No.

 

 

1 = Yes, Hub is part of a compound device.

2:1

Reserved

Reserved, always = ‘0’.

0

BOOST_IOUT

Upstream USB electrical signaling drive strength Boost Bit.

 

 

Note: This is used for long-trace length designs where additional electrical

 

 

signal boost may be required to support standard USB signal levels

 

 

at the far end of a cable.

 

 

‘0’ = Normal electrical drive strength.

 

 

‘1’ = Elevated electrical drive strength.

7.1.4.9Register 08h: Configuration Data Byte 3 (Reset = 0x00)

BIT

 

 

NUMBER

BIT NAME

DESCRIPTION

 

 

 

7:6

PRT_ASSIGN_MODE

Port Assignment Interface Mode:

 

 

‘00’ = Port Assign Interface is configured for Programmable Mode (8

 

 

configurations) (3-wire)

 

 

‘01’ = Port Assign Interface is configured for Direct Port Control. (4-Wire), Level

 

 

Sensitive.

 

 

‘10’ = Port Assign Interface is configured for Direct Port Control. (4-Wire), edge

 

 

Sensitive, and Unassigned state is not supported.

 

 

‘11’ = Port Assign Interface is configured for Direct Port Control. (4-Wire), edge

 

 

Sensitive, and the Unassigned state is supported.

Revision 1.91 (08-22-07)

24

SMSC USB2524

 

DATASHEET