The LT transmit block constructs a 4,384-bit frame, which contains a frame delimiter, control channel, and link training sequence. It is formatted as shown in the following figure.
Figure 1. Link Training Transmit
Recommended:
AMD recommends that the control channel bits not be changed by the link
training algorithm while the transmit state machine is transmitting them, otherwise, they
might be received incorrectly, possibly resulting in a DME error. This time begins when
tx_SOF is asserted and ends at least 288 bit times later, or approximately 30 ns. Note: Although the coefficient and status contain 128 bit times at the
line rate, the actual signaling rate for these two fields is reduced by a factor of 8.
Therefore, the DME clock rate is one quarter of the line rate.