DM9620 DAVICOM [Davicom Semiconductor, Inc.], DM9620 Datasheet - Page 31

• Manufacturer Part Number: DM9620
• Description: USB2.0 to 10/100M Fast Ethernet Controller
• Manufacturer: DAVICOM [Davicom Semiconductor, Inc.]

6.1 Basic Mode Control Register (BMCR) – 00H
Preliminary
Version: DM9620 -15-DS-P02
February 20, 2012
Bit
15
14
13
12
11
10
9
auto-negotiation
Speed selection
Auto-negotiatio
Power down
Bit Name
Loopback
n enable
Restart
Isolate
Reset
0, RW/SC
0,RW/SC
Default
0, RW
1, RW
1, RW
0, RW
0,RW
Reset:
1=Software reset
0=Normal operation
This bit sets the status and controls the PHY registers to their
default states. This bit, which is self-clearing, will keep returning a
value of one until the reset process is completed
Loopback:
Loop-back control register
1 = Loop-back enabled
0 = Normal operation
When in 100Mbps operation mode, setting this bit may cause the
descrambler to lose synchronization and produce a 1300ms "dead
time" before any valid data appear at the MII receive outputs
Speed select:
1 = 100Mbps
0 = 10Mbps
Link speed may be selected either by this bit or by auto-negotiation.
When auto-negotiation is enabled and bit 12 is set, this bit will return
auto-negotiation selected media type.
Auto-negotiation enable:
1 = Auto-negotiation is enabled, bit 8 and 13 will be in
auto-negotiation status
Power Down:
While in the power-down state, the PHY should respond to
management transactions. During the transition to power-down
state and while in the power-down state, the PHY should not
generate spurious signals on the MII.
1=Power down
0=Normal operation
Isolate:
1 = Isolates the PHY from the MII with the exception of the serial
management. (When this bit is asserted, the PHY does not respond
to the TXD[0:3], TX_EN, and TX_ER inputs, and it shall present a
high impedance on its TX_CLK, RX_CLK, RX_DV, RX_ER, RX[0:3],
COL and CRS outputs. When PHY is isolated from the MII it shall
respond to the management transactions)
0 = Normal operation
Restart auto-negotiation:
1 = Restart auto-negotiation. Re-initiates the auto-negotiation
process. When auto-negotiation is disabled (bit 12 of this register
cleared), this bit has no function and it should be cleared. This bit is
self-clearing and it will keep returning a value of 1 until
auto-negotiation is initiated by the PHY. The operation of the
auto-negotiation process will not be affected by the management
entity that clears this bit
0 = Normal operation
Description
USB2.0 to Fast Ethernet Controller
DM9620
31