This configuration gives the flexibility to switch the line rate between
40G to 50G and vice-versa any time. To activate this feature, select the check box
Runtime Switchable mode option in the
Configuration tab. When this option is selected speed can be changed by using
ch0_txrate
and ch0_rxrate
ports. Internally, the
GT IP will perform required DRP writes to get the desired speed. When this option is
selected the *_trans_debug
module is present inside the
*_pkt_gen_mon.v module of the example design.
This *_trans_debug
module is responsible for performing
all the GT DRP write operations to switch the transceiver mode, that is, 40G to 50G or
50G to 40G. When you set the mode_change_* input
signal
High for two clock cycles and then make it Low, it starts the DRP write operation to the
GT channel for the specific core and resets the specific core. The DRP writes are done
only for the channel. The QPLL0 of the common is fixed for the line rate 50G and the
QPLL1 is fixed for the line rate 40G.
The state transition occurred during this process is shown in the following figure.