ax88790 ASIX Electronics Corporation, ax88790 Datasheet - Page 28

• Manufacturer Part Number: ax88790
• Description: Pcmcia 10/100m Fast Ethernet Controller With Embedded Phy
• Manufacturer: ASIX Electronics Corporation

0.15 (SW_RESET)
0.14 (LOOPBACK)
0.13(SPEED100)
0.12 (NWAY_ENA)
0.11 (PWRDN)
0.10 (ISOLATE)
0.9 (REDONWAY)
0.8 (FULL_DUP)
0.7 (COLTST)
0.6:0 (RESERVED)
4.4.1 MR0 -- Control Register Bit Descriptions
FIELD
AX88790 L
TYPE
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
NA
Reset. Setting this bit to a 1 will reset the PHY. All registers will be set to
their default state. This bit is self-clearing. The default is 0.
Loopback. When this bit is set to 1, no data transmission will take place on
the media. Any receive data will be ignored. The loopback signal path will
contain all circuitry up to, but not including, the PMD. The default value is
a 0.
Speed Selection. The value of this bit reflects the current speed of operation
(1 =100 Mbits/s; 0 =10 Mbits/s). This bit will only affect operating speed
when the autonegotiation enable bit (register 0, bit 12) is disabled (0). This
bit is ignored when autonegotiation is enabled (register 0, bit 12). This bit is
ANDed with the SPEED_PIN signal.
Autonegotiation Enable. The autonegotiation process will be enabled by
set-ting this bit to a 1. The default state is a 1.
Powerdown. The PHY may be placed in a low-power state by setting this bit
to a 1, both the 10Mbits/s transceiver and the 100Mbits/s transceiver will be
powered down. While in the powerdown state, the PHY will respond to
management transactions. The default state is a 0.
Isolate. When this bit is set to a 1, the MII outputs will be brought to the
high-impedance state. The default state is a 0.
Restart Autonegotiation. Normally, the autonegotiation process is started
at powerup. Setting this bit to a 1 may restart the process. The default state is
a 0. The NWAYDONE bit (register 1, bit 5) is reset when this bit goes to a
1. This bit is self-cleared when autonegotiation restarts.
Duplex Mode. This bit reflects the mode of operation (1 = full duplex; 0 =
half duplex). This bit is ignored when the autonegotiation enable bit
(register 0, bit 12) is enabled. The default state is a 0. This bit is ORed with
the F_DUP pin.
Collision Test. When this bit is set to a 1, the PHY will assert the MCOL
signal in response to MTX_EN.
Reserved. All bits will read 0.
3-in-1 PCMCIA Fast Ethernet Controller
28
DESCRIPTION
ASIX ELECTRONICS CORPORATION