The TX portion of the OOBFC starts transmitting information as soon as the
reset input is deasserted. The clk_tx_ref input
must be stable and running correctly before the reset input is deasserted.
The health status inputs (tx_intf_status and
tx_lane_status) are transmitted only when an unhealthy condition
exists. An unhealthy condition occurs when tx_intf_status is 0, or any
bit of tx_lane_status is 0. The transmission of the status inputs is
alternated with the transmission of the flow control information when an unhealthy
status exists.
If the health status inputs (tx_intf_status and
tx_lane_status) are all 1, meaning the interface is healthy, only
flow control information is transmitted.
The length of the flow control calendar is programmed through
tx_callen_minus1. The calendar is transmitted with the value of
tx_fc[0] sent first, tx_fc[1] sent second,
tx_fc[2] sent third, and so on.
The tx_fc input is latched for transmission in 64-bit groups. The input
tx_fc[63:0], tx_intf_status, and
tx_lane_status are latched at the completion of the clock cycle
when tx_update[0] is asserted; the input tx_fc[127:64]
is latched at the completion of the clock cycle when tx_update[1] is
asserted; the input tx_fc[191:128] is latched at the completion of the
clock when tx_update[2] is asserted, and so on.