MDS213 Datasheet, PDF (91/120 Pages) Zarlink Semiconductor Inc – 12-Port 10/100Mbps + 1Gbps Ethernet Switch

MDS213
Data Sheet
18.2.10.10 ACKTM - Timer For SOF Checking
Access: Non-Zero-Wait-State,
Direct Access, Write/Read
Address: h610
31
10 9
0
XOFF_CKTM
Bit [9:0] XOFF_CKTM
The time out value to check SOF after XOFF
Bit [31:10] Reserved
Note that the purpose of this timer is to avoid continuously sending the XOFF frames. The XOFF Frame is triggered
by the incoming frames when no resources are available in the DS chip. Ideally, after the first XOFF frame is sent
out, we expect no frames to be received until we send out the XON frame. However, the connected device may not
interpret XOFF frames correctly (or may react slowly) and still keep sending data frames to this congested port. In
this case, the congested port will want to send another XOFF frame each time another frame is received. To avoid
this scenario, we set the ACKTM timer to prevent the congested port from sending XOFF frames for every incoming
frame in congestion period before the timer expires.
18.2.10.11 AFCHT10 - Flow Control Hold Time Of 10Mbps Port
Access: Non-Zero-Wait-State,
Direct Access, Write/Read
Address: h620
31
16 15
0
HBK_TM_10
Bit [15:0] HBK_TM_10
Bit [31:16] Reserved
Holding time to remote station for 10Mbps port when the chip
detects the head of line blocking counter has run out. The holding
time value is embedded in the flow control frame sent to the remote
station.
18.2.10.12 AFCHT 100 - Flow Control Hold Time Of 100Mbps Port
Access: Non-Zero-Wait-State,
Direct Access,
Write/Read
Address: h624
31
16 15
0
HBK_TM_100
Bit [15:0] HBK_TM_100
Bit [31:16] Reserved
Holding time to remote station for 100Mbps port when the chip
detects the head of line blocking counter has run out. The holding
time value is embedded in the flow control frame sent to the remote
station.
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