
Chapter 4: Backplane Ethernet 10GBASE-KR PHY IP Core 4–17
Daisy-Chain Mode
November 2012 Altera CorporationAltera Transceiver PHY IP Core
User Guide
Daisy-Chain Mode
Figure 4–6 illustrates equalization in daisy-chain mode. In daisy-chain mode the
devices are connected over a backplane in a daisy-chain topology instead of in a spoke
and hub or switch topology.
In Figure 4–6, data transmission proceeds clockwise from link partner A, to B, to C. TX
equalization includes the following steps which are identified in Figure 4–6:
1. The receiving partner B calculates the BER for data received from transmitting
partner A.
2. The receiving partner B sends updates for TX link partner C.
3. The receiving link partner C transmits an update to the transmitting link partner
A.
4. Transmit partner A updates its equalization settings.
5. Transmit partner A acknowledges the change.
This procedure is repeated for the other two link partners.
Figure 4–6. TX Equalization in Daisy Chain Mode
RX
Encode
Handshake
Adapt
TX
dmi*
dmi*
dmi*
dmo*
dmo*
Partner A
Parter C
Parter B
Eq
Decode
RX
Encode
Handshake
Adapt
TX
Eq
Decode
Change Eq
Ack
Change
Data Transmission
Adaptation Feedback
Change Eq
Ack Change
Feedback/Handshake via Management
RX
Encode
Handshake
Adapt
TX
Eq
Decode
Change Eq
Ack Change
1
2
3
4
5
dmo*
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