Altera Interlaken MegaCore Function - Manual (Page 50)

4–24 Chapter 4: Functional Description
Out-of-Band Flow Control Block
Interlaken MegaCore Function June 2012 Altera Corporation
User Guide
The 12-lane, 10.3125-Gbps variations use four PMAs in each of three transceiver
blocks, with datapath width 40 bits rather than the 20 bits shown in
Figure 4–18 .
A four-lane variation is configured with a single transceiver block, an eight-lane
variation is configured with two transceiver blocks, and a 12-lane variation is
configured with three transceiver blocks. These variations use four out of the six PMA
blocks in each transceiver block. A 10-lane variation is configured with two
transceiver blocks, and a 20-lane variation is configured with four transceiver blocks.
These variations use five out of the six PMA blocks in each transceiver block. Because
using five of the PMA blocks requires that one CMU channel be used, the transceivers
are configured in PMA Direct mode. When only four of the PMA blocks are used, the
transceivers are configured in low latency PCS mode.
Out-of-Band Flow Control Block
Altera supports the optional inclusion of an out-of-band flow control block in your
Interlaken MegaCore function. If you turn on Enable out-of-band flow control, the
block is configured in your MegaCore function. The block has an out-of-band flow
control interface, as defined in Section 5.3.4.2 of the Interlaken Protocol Definition,
Revision 1.2. You must connect the six signals in this interface to device pins.
On the application side, the out-of-band flow control block can receive link status,
lane status, and calendar bits from the application, and transmit them on the TX
out-of-band flow control interface to a downstream RX out-of-band flow control block
associated with the Interlaken link partner. It can also transmit link status, lane status,
and calendar bits to the application, after it receives them on the RX out-of-band flow
control interface from an upstream TX out-of-band flow control block associated with
the Interlaken link partner.
RX Out-of-Band Flow Control Block
The RX out-of-band flow control block can receive calendar bits from an upstream TX
out-of-band flow control block associated with the Interlaken link partner, and
transmit link status, lane status, and the original calendar bits to the application.
Figure 4–19. Transceiver Block Use in 10- and 20-lane Variations
lane
lane
lane
lane
20
20
20
20 FPGA
PCS
PCS
PCS
PCS
PMA
PMA
PMA
PMA
PMA
PMA
ALTGX
ALTGX
ALTGX
ALTGX
lane
20
ALTGX