HS_Media independent interface (MII)
RM0082
536/844
Doc ID 018672 Rev 1
Note:
In half-duplex mode, the minimum IFG can be configured up to 64 bit times (IFG = 3'b100).
●
DCRS
When set high, this bit makes the MAC transmitter ignore the MII CRS signal during
frame transmission in half-duplex mode. This request results in no errors generated
due to Loss of Carrier or No Carrier during such transmission. When this bit is low, the
MAC transmitter generates such errors due to Carrier Sense and will even abort the
transmissions.
●
DO
Setting this bit, the MAC disables the reception of frame when the
mii_txen_o
is
asserted in half-duplex mode. Otherwise, the MAC receives all packets that are given
by the PHY while transmitting.
Note:
This bit is not applicable (RO with default value) if the MAC is operating in full-duplex.
●
LM
Setting this bit, the MAC operates in loop-back mode at MII. In this mode, the MII
receive clock input is required for the loop-back to work properly.
●
DM
Setting this bit, the MAC operates in a full-duplex mode where it can transmit and
receive simultaneously.
Note:
This bit is RO with default value of 1'b1 in full-duplex only configuration.
●
IPC
Setting this bit, the MAC calculates the 16 bit 1's complement of the 1's complement
sum of the payload data (16 bit) and sends it to the application at the end of frame.
●
DR
Setting this bit, the MAC will attempt only one transmission. In case of a collision, the
MAC will ignore the current frame transmission and report a Frame Abort with
excessive collision error in the transmit frame status.
Clearing this bit, the MAC will attempt retries based on the settings of BL field in this
register (bits [06:05]).
Note:
This bit is applicable only to half-duplex mode and it is reserved in full-duplex only
configuration.
●
ACS
Setting this bit, the MAC will strip the Pad/FCS field on incoming frames only if the
length's field value is less than or equal to 1500 bytes. All received frames with length
Table 444.
IFG field bit assignments
Value
Inter Frame Gap
3‘b000
96 bit times
3‘b001
88 bit times
3‘b010
80 bit times
...
...
3‘b111
40 bit times