Persist Option - Persist Option - UG570

The persist bitstream option (BITSTREAM.CONFIG.PERSIST YES) maintains the configuration logic access to the multi-function configuration pins after configuration. The persist option is primarily used to maintain the SelectMAP port after configuration for readback access, but persist can be used with any configuration mode. Persist is not needed for JTAG configuration as the JTAG port is dedicated and always available. The persist option can also be used to reconfigure the device from an external controller without pulsing the PROGRAM_B pin or using the JTAG port. Persist and ICAP cannot be used at the same time. Persist is also not recommended for standard Master SPI/BPI configuration mode setups.

The multi-function pins that persist depend on the configuration mode pin settings. The following table shows which UltraScale or UltraScale+ multi-function configuration pins persist on bank 65 when the persist bitstream option is selected. Any I/O pins that persist cannot be used as I/O in the user design. Use the CONFIG_MODE constraint to reserve the correct pins during implementation of the design. Persisted I/O use the standard default of LVCMOS, 12 mA drive, fast slew rate.