AM79C873 Advanced Micro Devices, AM79C873 Datasheet - Page 27

• Manufacturer Part Number: AM79C873
• Description: NetPHY -1 10/100 Mbps Ethernet Physical Layer Single-Chip Transceiver with 100BASE-FX Support
• Manufacturer: Advanced Micro Devices

AMD Specified Configuration Register (DSCR) -
Register 16
16.15
16.14
16.13
16.12
16.11
16.10
16.9
16.8
16.7
16.6
Bit
CLK25MDIS
F_LINK_100
REPEATER
BP_ALIGN
Bit Name
BP_4B5B
Reserved
Reserved
BP_SCR
UTP
TX
Pin 97, RW
Pin 98, RW
Pin 94, RW
Default
0, RW
1, RW
1, RW
0, RW
1, RW
0, RW
, RW
P R E L I M I N A R Y
Bypass 4B5B Encoding and 5B4B Decoding:
1=4B5B encoder and 5B4B decoder function bypassed.
0=Normal 4B5B and 5B4B operation The value of the pin is latched into
this bit at power-up/reset.
Bypass Scrambler/Descrambler Function:
1=Scrambler and descrambler function bypassed.
0=Normal scrambler and descrambler operation.
The value of the input pin is latched into this bit at power-up/reset.
Bypass Symbol Alignment Function:
1= Receive functions (descrambler, symbol alignment and symbol
decoding functions) bypassed. Transmit functions (symbol encoder and
scrambler) bypassed.
0= Normal operation.
The value of the BPALIGN input pin is latched into this bit at power-up/
reset.
Reserved:
This bit must be set as 0.
Repeater/Node Mode:
1=Repeater mode.
0=Node mode.
In Repeater mode, the Carrier Sense (CRS) output from the NetPHY-1
device will be asserted only by receive activity. In NODE mode, or a mode
not configured for Full Duplex operation, CRS will be asserted by either
receive or transmit activity.
The value of the RPTR/NODE input pin is latched into this bit at power-up
reset.
100BASE-TX or FX Mode Control:
1=100BASE-TX operation.
0=100BASE-FX operation.
UTP Cable Control:
1=The media is a UTP cable, 0=STP.
CLK25M Disable:
1=CLK25M output clock signal tri-stated.
0=CLK25M enabled.
This bit should be set to 1 to disable the 25 MHz output and reduce ground
bounce and power consumption. For applications requiring the CLK25M
output, set this bit to 0.
Force Good Link in 100 Mbps:
1=Normal 100 Mbps operation.
0=Force 100 Mbps good link status.
This bit is useful for diagnostic purposes.
Reserved:
This bit must be written as 0.
Am79C873
Description
27