ASIX ELECTRONICS CORPORATION

27

AX88772

USB to 10/100 Fast Ethernet/HomePNA Controller

6.2.1.23 Software Reset Register (20h, write only)

Bit7

Bit6

Bit5

Bit4

Bit3

Bit2

Bit1

Bit0

Reserved

IPPD

IPRL

BZ

PRL

PRTE

RT

RR

RR: Clear frame length error for Bulk In.

1: set high to clear state.

0: set low to exit clear state (default).

RT: Clear frame length error for Bulk Out.

1: set high to enter clear state.

0: set low to exit clear state (default).

PRTE: External Phy Reset pin Tri-state Enable.

1: Enable, i.e., the external PHYRST_N pin is tri-stated (default). This allows the PHYRST_N pin’s active level to

be controlled by external pulled-up (active high during power-on) or pulled-down resistor (active low during

power-on).

0: Disabled, i.e., the external PHYRST_N pin’s level is driven by either PRL bit or internal “USB RESET” based on

the setting in SCPR bit in Flag byte of EEPROM.

PRL: External Phy Reset pin Level. When SCPR bit = 1 and PRTE = 0, this bit controls the output level of external

PHYRST_N pin.

1: Set to high (default).

0: Set to low.

BZ: Force Bulk In to return a Zero-length packet.

1: Software can force Bulk In to return a zero-length USB packet.

0: Normal operation mode (default).

IPRL: Internal Phy Reset control. When SCPR bit = 1, this bit acts as reset signal of internal Ethernet Phy.

1: Internal Ethernet Phy is in operating state.

0: Internal Ethernet Phy in reset state (default).

IPPD: Internal Ethernet Phy Power Down control.

1: Internal Ethernet Phy is in power down mode (default).

0: Internal Ethernet Phy is in operating mode.

6.2.1.24 Software PHY Select Status Register (21h, read only) and Software PHY Select Register

22h, write only)

Bit7

Bit6

Bit5

Bit4

Bit3

Bit2

Bit1

Bit0

Reserved

ASEL

PSEL

PSEL: Phy Select, when ASEL = 0 (manually select the Phy to operate)

1: Select embedded 10/100 Ethernet Phy (default).

0: Select external Phy, which is attached to the MII interface

ASEL: Auto Select or Manual Select

1: Automatically select based on link status of embedded 10/100 Ethernet Phy (default).

0: Manually select between the embedded 10/100 Ethernet Phy and the external one.