USB3803 datasheet(67/99 Pages) MICROCHIP

67 / 99 page

 2014-2015 Microchip Technology Inc.

DS00001691B-page 67

USB3803

NbrPorts

user

Number of downstream facing ports this Hub supports.

See Section 11.23.2.1 of the USB Specification for addi-

tional details regarding the use of this field.

The value reported is implementation dependent, and is

derived from the value defined during Internal Default, or

serial port load. The PORT_DIS_SP field defines the

ports that are permanently disabled when in Self-Pow-

ered operation, and the PORT_DIS_BP field defines the

ports that are permanently disabled when in Bus-Pow-

ered operation.

Internal logic will subtract the number of ports which are

disabled, from the total number available (which is 3),

and will report the remainder as the number of ports

supported. The value reported to the host must coincide

with the current operating mode, and will be determined

by the following rules.

The field used to determine the value that is reported to

the host will be:

‘PORT_DIS_BP’ if SELF_BUS_PWR = ‘0’

‘PORT_DIS_SP’ if SELF_BUS_PWR = ‘1’

HubCharacteristics

user

Defines support for Logical power switching mode,

Compound Device support, Over-current protection, TT

Think Time, and Port Indicator support, See Section

11.23.2.1 in the USB Specification for additional details

regarding the use of this field.

The values delivered to a host are all derived from val-

ues defined during Internal Default, or serial port load,

and are assigned as follows:

D1:0 = ‘00’b if PORT_PWR = ‘0’

D1:0 = ‘01’b if PORT_PWR = ‘1’

D2 = ‘COMPOUND’

D4:3 = ‘CURRENT_SNS’

D6:5 = ‘00’b for 8FS (max) bit times of TT think time.

D7 = hardcoded to ‘0’ (no Port Indicator Support)

D15:8 = ‘00000000’b

PwrOn2PwrGood

user

Time (in 2 ms intervals) from the time the power-on

sequence begins on a port until power is good on that

port. See Section 11.23.2.1 in the USB Specification.

The value contained in the ‘POWER_ON_TIME’ field is

directly reported to the host, and is determined by Inter-

nal Default, or serial port load.

TABLE 7-33:

CLASS-SPECIFIC HUB DESCRIPTOR (FULL-SPEED & HIGH-SPEED) (CONTINUED)

Offset

Field

Size

Value

Description

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