USB3803 datasheet(24/99 Pages) MICROCHIP

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USB3803

DS00001691B-page 24

 2014-2015 Microchip Technology Inc.

5.3.7

Bit Number

Bit Name

Description

7SELF-

_BUS_PWR

Self or Bus Power: Selects between Self- and Bus-Powered operation.

The Hub is either Self-Powered (draws less than 2mA of upstream bus power) or

Bus-Powered (limited to a 100mA maximum of upstream power prior to being

configured by the host controller).

When configured as a Bus-Powered device, the Microchip Hub consumes less

than 100mA of current prior to being configured. After configuration, the Bus-

Powered Microchip Hub (along with all associated hub circuitry, any embedded

devices if part of a compound device, and 100mA per externally available down-

stream port) must consume no more than 500mA of upstream VBUS current.

The current consumption is system dependent, and the customer must ensure

that the USB 2.0 specifications are not violated.

When configured as a Self-Powered device, <1mA of upstream VBUS current is

consumed and all ports are available, with each port being capable of sourcing

500mA of current.

This field is set by the customer using the serial interface options.

0 = Bus-Powered operation.

1 = Self-Powered operation.

Reserved

HS_DISABLE

High Speed Disable: Disables the capability to attach as either a High/Full-

speed device, and forces attachment as Full-speed only i.e. (no High-Speed

support).

0 = High-/Full-Speed.

1 = Full-Speed-Only (High-Speed disabled!)

MTT_ENABLE Multi-TT enable: Enables one transaction translator per port operation.

Selects between a mode where only one transaction translator is available for all

ports (Single-TT), or each port gets a dedicated transaction translator (Multi-TT)

{Note: The host may force Single-TT mode only}.

0 = single TT for all ports.

1 = one TT per port (multiple TT’s supported)

EOP_DISABLE EOP Disable: Disables EOP generation of EOF1 when in Full-Speed mode.

During FS operation only, this permits the Hub to send EOP if no downstream

traffic is detected at EOF1. See Section 11.3.1 of the USB 2.0 Specification for

additional details. Note: generation of an EOP at the EOF1 point may prevent a

Host controller (operating in FS mode) from placing the USB bus in suspend.

0 = An EOP is generated at the EOF1 point if no traffic is detected.

1 = EOP generation at EOF1 is disabled (note: this is normal USB operation).

Note:

This is a rarely used feature in the PC environment, existing drivers

may not have been thoroughly debugged with this feature enabled. It

is included because it is a permitted feature in Chapter 11 of the USB

specification.

USB3803 Datasheet(PDF) 24 Page - Microchip Technology

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