9.2. TX Out‑of‑Band Flow Control Signals
The transmit out‑of‑band flow control interface receives calendar and status information, and transmits flow‑control clock, data, and sync signals. The TX Out-of-Band Flow Control Interface Signals table describes the transmit out‑of‑band flow control interface signals specified in the Interlaken Protocol Specification, Revision 1.2. The TX Out-of-Band Flow Control Block Signals for Application Use table describes the signals on the application side of the TX out‑of‑band flow control block.
|   Signal Name  |  
         Direction  |  
         Width (Bits)  |  
         Description  |  
      
|---|---|---|---|
|   fc_clk  |  
         Output  |  
         1  |  
         Output reference clock to a downstream out-of-band RX block. Clocks the fc_data and fc_sync signals. You must connect this signal to a device pin.  |  
      
|   fc_data  |  
         Output  |  
         1  |  
         Output serial data pin to a downstream out-of-band RX block. You must connect this signal to a device pin.  |  
      
|   fc_sync  |  
         Output  |  
         1  |  
         Output sync control pin to a downstream out-of-band RX block. You must connect this signal to a device pin.  |  
      
|   Signal Name  |  
         Direction  |  
         Width (Bits)  |  
         Description  |  
      
|---|---|---|---|
|   double_fc_clk  |  
         Input  |  
         1  |  
         Reference clock for generating the flow control output clock fc_clk. The frequency of the double_fc_clk clock must be double the intended frequency of the TX fc_clk output clock.  |  
      
|   double_fc_arst  |  
         Input  |  
         1  |  
         Asynchronous reset for the out-of-band TX block.  |  
      
|   ena_status  |  
         Input  |  
         1  |  
         Enable transmission of the lane status and link status to the downstream out-of-band RX block. If this signal is asserted, the lane and link status information is transmitted on fc_data. If this signal is not asserted, only the calendar information is transmitted on fc_data.  |  
      
|   lane_status  |  
         Input  |  
         Number of Lanes  |  
         Lane status to be transmitted to a downstream out-of-band RX block if ena_status is asserted. Width is the number of lanes.  |  
      
|   link_status  |  
         Input  |  
         1  |  
         Link status to be transmitted to a downstream out-of-band RX block if ena_status is asserted.  |  
      
|   calendar  |  
         Input  |  
         16  |  
         Calendar status to be transmitted to a downstream out-of-band RX block.  |