Agere Systems Inc.
135
Data Sheet
July 2001
T8302 Internet Protocol Telephone
Advanced RISC Machine (
ARM
)
11 10/100 2-Port Repeater and Backplane Segment Controller
(continued)
11.5.2 Global Configuration Register
The
global configuration register
is used to configure the repeater slice features that affect the operation of all
four ports.
Table 115. Global Configuration Register
Address 0xE001 200C
3
RSVD
Bit #
Name
Bit #
31:6
5:4
31:6
RSVD
Name
RSVD
REPEATER
BYPASS
5:4
2
1
0
REPEATER BYPASS
State on RST
(0)
(00)
TXCPIN
Description
GPSFD
RSVD
Reserved. All bits should be written to 0.
Repeater bypass mode. Repeater bypass mode set:
00
01
10
11
Reserved. Should be written to 0.
MII 100 Mbits/s mode
TXCPIN
enable.
PHY0
MAC
PHY1
MAC
Reserved
Repeater is in normal mode of operation
3
2
RSVD
TXCPIN
—
(0)
The 10 Mbits/s mode will always use the
TX_CLK
from the PHY regard-
less of the setting of this bit. When programmed high,
TX_CLK
is used
to transfer 100 Mbits/s mode transmit data and control out of the
repeater slice to the PHY. When programmed low (default), all ports will
clock out transmit data and are controlled with the internal 25 MHz clock
that is a delayed version of the
MSTCLK
input to the repeater slice. This
mode reduces latency.
In 100 Mbits/s mode, this bit sets the clocking mode for MII PHY transmit
data and control for both slices of the repeater slice.
Global speed select. This bit selects the speed of the repeater.
1
GSPS
(1)
If
GSPS
= 0, the repeater speed is set to 10 Mbits/s. This will force both
ports and backplane into the 10 Mbits/s mode. If
GSPS
= 0 and
RX_CLK
from either PHY port is not 10 MHz, speed mismatch will be
detected and the corresponding bit in the
port status register
will be
set.
If
GSPS
= 1, the repeater speed is set to 100 Mbits/s. This will force both
ports and backplane into the 100 Mbits/s mode. If
GSPS
= 1 and
RX_CLK
from either PHY port is not 25 MHz, speed mismatch will be
detected and they corresponding bit in the
port status register
will be
set.
Default = 1.
Reserved.
Should be written to 0.
0
RSVD
—