dp83820 National Semiconductor Corporation, dp83820 Datasheet - Page 56

• Manufacturer Part Number: dp83820
• Description: 10/100/1000 Mb/s Pci Ethernet Network Interface Controller
• Manufacturer: National Semiconductor Corporation

4.0 Register Set
25-24
23-22
21-20
19-18
15-0
26
17
16
PAUSE_CNT Pause Counter Value
PS_STLO
PS_FFLO
PS_STHI
PS_FFHI
PS_TX
(Continued)
RX Stat FIFO Hi Threshold
RX Stat FIFO Lo Threshold
RX Data FIFO Hi Threshold
RX Data FIFO Lo Threshold
Transmit Pause Frame
Reserved
unused - returns 0
Status FIFO Threshold for initiating a pause frame with a length field of 0.
This allows termination of an active pause interval when the status FIFO
has enough space available. The following encoding determines when a
length 0 pause frame will be sent:
00: Disabled
01: 2 or more packets available
10: 4 or more packets available
11: 8 or more packets available
This value, if enabled, should always be equal to or greater than the low
threshold (PS_STLO). When disabling the high threshold, the PS_FFHI
field should also be set to disabled.
Status FIFO Threshold for initiating a pause frame. Upon reception of a
valid packet, a pause frame will be transmitted if space remaining in the
status FIFO is less than the threshold value. The encoding is as follows:
00: Disabled
01: Less than 2 packets available
10: Less than 4 packets available
11: Less than 8 packets available
Data FIFO Threshold for initiating a pause frame with a length field of 0.
This allows termination of an active pause interval when the data FIFO has
enough space available. The following encoding determines when a length
0 pause frame will be sent:
00: Disabled
01: 2K or more bytes available
10: 4K or more bytes available
11: 8K or more bytes available
This value, if enabled, should always be equal to or greater than the low
threshold (PS_FFLO). When disabling the high threshold, the PS_STHI
field should also be set to disabled.
Data FIFO Threshold for initiating a pause frame. Upon reception of a valid
packet, a pause frame will be transmitted if space remaining in the data
FIFO is less than the threshold value. The encoding is as follows:
00: Disabled
01: Less than 2K bytes available
10: Less than 4K bytes available
11: Less than 8K bytes available
This is a manual method of sending a pause frame. This bit will remain set
until the pause frame is transmitted. R/W
Reserved. R/W
Pause Length field which will be sent in a Transmit Pause frame. R/W
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