Ethernet Subsystem Registers
Table 14-190. MACCONTROL Register Field Descriptions (continued)
Bit
Field
Type
Reset
Description
18
EXT_EN
R/W
0h
Mode of operation.
0 - Forced mode of operation.
1 - In-band mode of operation.
17
GIG_FORCE
R/W
0h
Gigabit Mode Force - This bit is used to force the CPGMAC_SL into
gigabit mode if the input GMII_MTCLK has been stopped by the
PHY.
16
IFCTL_B
R/W
0h
Connects to the speed_in input of the respective RMII gasket.
When using RMII mode:
0 - 10Mbps operation
1 - 100Mbps operation
15
IFCTL_A
R/W
0h
Connects to the speed_in input of the respective RMII gasket.
When using RMII mode:
0 - 10Mbps operation
1 - 100Mbps operation
14-12
Reserved
R
0h
11
CMD_IDLE
R/W
0h
Command Idle
0 - Idle not commanded
1 - Idle Commanded (read idle in MacStatus)
10
TX_SHORT_GAP_EN
R/W
0h
Transmit Short Gap Enable
0 - Transmit with a short IPG is disabled
1 - Transmit with a short IPG (when TX_SHORT_GAP input is
asserted) is enabled.
9-8
Reserved
R
0h
7
GIG
R/W
0h
Gigabit Mode -
0 - 10/100 mode
1 - Gigabit mode (full duplex only) The GIG_OUT output is the value
of this bit.
6
TX_PACE
R/W
0h
Transmit Pacing Enable
0 - Transmit Pacing Disabled
1 - Transmit Pacing Enabled
5
GMII_EN
R/W
0h
GMII Enable -
0 - GMII RX and TX held in reset.
1 - GMII RX and TX released from reset.
4
TX_FLOW_EN
R/W
0h
Transmit Flow Control Enable - Determines if incoming pause
frames are acted upon in full-duplex mode.
Incoming pause frames are not acted upon in half-duplex mode
regardless of this bit setting.
The RX_MBP_Enable bits determine whether or not received pause
frames are transferred to memory.
0 - Transmit Flow Control Disabled.
Full-duplex mode - Incoming pause frames are not acted upon.
1 - Transmit Flow Control Enabled .
Full-duplex mode - Incoming pause frames are acted upon.
3
RX_FLOW_EN
R/W
0h
Receive Flow Control Enable -
0 - Receive Flow Control Disabled Half-duplex mode - No flow
control generated collisions are sent.
Full-duplex mode - No outgoing pause frames are sent.
1 - Receive Flow Control Enabled Half-duplex mode - Collisions are
initiated when receive flow control is triggered.
Full-duplex mode - Outgoing pause frames are sent when receive
flow control is triggered.
2
MTEST
R/W
0h
Manufacturing Test mode - This bit must be set to allow writes to the
Backoff_Test and PauseTimer registers.
1
LOOPBACK
R/W
0h
Loop Back Mode - Loopback mode forces internal fullduplex mode
regardless of whether the fullduplex bit is set or not.
The loopback bit should be changed only when GMII_en is
deasserted.
0 - Not looped back
1 - Loop Back Mode enabled
1414
Ethernet Subsystem
SPRUH73H – October 2011 – Revised April 2013
Copyright © 2011–2013, Texas Instruments Incorporated