Controller Constraints - 4.1 English

Soft Error Mitigation Controller Product Guide (PG036)

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4.1 English

The controller, considered in isolation and regardless of options at generation, is a fully synchronous design. Fundamentally, it only requires a clock period constraint on the master clock input. In the generic XDC, this constraint is placed on the system-level design example clock input and propagated into the controller. The constraint is discussed in Example Design Constraints .

The signal paths between the controller and the FPGA configuration system primitives must be considered as synchronous paths. By default, the paths between the internal configuration access port (ICAP) primitive and the controller are analyzed as part of a clock period constraint on the master clock, because the ICAP clock pin is required to be connected to the same master clock signal.

However, the situation is different for the FRAME_ECC primitive, as it does not have a clock pin. Based on the specific use of the FRAME_ECC primitive with the ICAP primitive, it is known that FRAME_ECC primitive pins are synchronous to the master clock signal. Therefore, additional constraints with values derived from the clock period constraint are added:

set_max_delay 12.151 -from [get_pins example_cfg/example_frame_ecc/*] -quiet -datapath_only

set_max_delay 30.302 -from [get_pins example_cfg/example_frame_ecc/*] -to [all_outputs] -quiet -datapath_only