The Interlaken 600G IP core implements the Interlaken in-band flow control mechanism as described in section 5.3.4 of the Interlaken Protocol Definition, Revision 1.2. This mechanism communicates XON/XOFF (for example, for different channels) using the In-Band Flow Control bits of Control words. Additionally, the Multiple Use bits of Control Words can be used in a similar manner.
Inside each Interlaken Control Word are 16 bits of In-Band Flow Control information,
bits[55:40], and a Reset Calendar bit, bit[56]. These bits are shared over the calendar
length as described in the following subsections. The Interlaken 600G core has a fixed calendar length and provides one
transmit bit and one receive bit for each calendar entry.
Note: The MAX_CALLEN parameter represents the supported calendar
length for each specific Interlaken 600G IP
core configuration.
By definition, XON is represented by 1, and XOFF is represented by 0 for both
the transmitter and the receiver. All signals are synchronous with the rising edge of
clk, and a detailed description of each signal follows.