USB251 datasheet(24/57 Pages) MICROCHIP

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USB251xB/xBi

DS00001692C-page 24

 2010 - 2015 Microchip Technology Inc.

5.1.10

5.1.11

Bit Number

Bit Name

Description

7:0

NR_DEVICE

Non-Removable Device: indicates which port has a non-removable device.

: port is removable

: port is non-removable

Bit 7 : rsvd

Bit 6 : rsvd

Bit 5 : rsvd

Bit 4 : controls port 4

Bit 3 : controls port 3

Bit 2 : controls port 2

Bit 1 : controls port 1

Bit 0 : rsvd

Note:

The device must provide its own descriptor data.

When using the default configuration, the NON_REM[1:0] pins will designate

the appropriate ports as being non-removable.

Bit Number

Bit Name

Description

7:0

PORT_DIS_SP

Port Disable Self-Powered: disables one or more ports.

= port is available

= port is disabled

Bit 7 : rsvd

Bit 6 : rsvd

Bit 5 : rsvd

Bit 4 : controls port 4

Bit 3 : controls port 3

Bit 2 : controls port 2

Bit 1 : controls port 1

Bit 0 : rsvd

During self-powered operation when mapping mode is disabled (PRTMAP_EN

= 0), this register selects the ports that will be permanently disabled. These

ports are then unavailable and cannot be enabled or enumerated by a host

controller. The ports can be disabled in any order, where the internal logic will

automatically report the correct number of enabled ports to the USB host. The

active ports will be reordered in order to ensure proper function.

When using the default configuration, PRT_DIS_P[x:1] and PRT_DIS_M[x:1]

pins disable the appropriate ports.

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