HS_Media independent interface (MII)
RM0082
542/844
Doc ID 018672 Rev 1
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PT
This 16 bit field represents the value (expressed as an integer number of slot times) to
be used in the Pause Time field in the transmit control frame.
●
DZPQ
When set, this bit disables the automatic generation of Zero-Quanta Pause Control
frames on the deassertion of the flow-control signal from the FIFO layer (MTL flow
control signal). When this bit is reset, normal operation with automatic Zero-Quanta
Pause Control frame generation is enabled.
●
PLT
This 2 bit field allows configuration of the threshold of the PAUSE timer at which the
input flow control is checked for automatic re-transmission of PAUSE frame, according
to encoding below:
where, Pause Time is configured by the PT field in this register (see above), and slot time is
the time taken to transmit 512 bits (64 bytes) on the MII interface.
Note:
The threshold value specified by PLT should be always greater than the Pause Time (PT
field).
●
UP
Setting this bit, the MAC will detect the Pause frames with the station's unicast address
specified in MAC Address0 High register (section 1.4.2.24) and MAC Address0 Low
Table 451.
Flow control register bit assignments
Bit
Name
Reset Value
Type
Description
[31:16]
16’h0
RW
Pause Time.
[15:08]
Reserved
-
RO
Read: undefined.
[7]
1’b0
RW
Disable Zero-Quanta Pause
[6]
Reserved
-
RO
Read: undefined
[05:04]
2’h0
RW
Pause Low Threshold.
[03]
1’h0
RW
Unicast Pause Frame Detect.
[02]
1’h0
RW
Receive Flow Control Enable.
[01]
1’h0
RW
Transmit Flow Control Enable.
[00]
1’h0
RW
Flow Control Busy/Back-Pressure
Activate.
Table 452.
PLT field bit assignments
Value
Threshold
2‘b00
Pause Time - 4 slot time
2‘b01
Pause Time - 28 slot time
2‘b10
Pause Time - 144 slot time
2‘b11
Pause Time - 256 slot time