- Tandem PROM requires PERSIST to be set to reserve
dual-purpose I/O for programming usage. Because of this, the configuration flash cannot be
accessed by the user design after Tandem PROM configuration completes. Tandem PCIe should be used if configuration flash update from the FPGA user design
is required.
- The use of Tandem PROM with
PERSIST also disables the ICAP. This resource is not available
post-configuration for DFX or other functions.
- Tandem with Field Updates is supported for UltraScale and UltraScale+
devices only. This solution will never support 7 series devices. For this type of approach in 7 series, a general Dynamic Function eXchange solution should be
considered.
- General Tandem + Dynamic Function eXchange is also
supported. To enable, simply use the standard Tandem option when
generating the PCIe IP then add it to a DFX design to be compiled in
non-project mode as described in Non-Project Flow, and the
Vivado
Design Suite User Guide: Dynamic Function eXchange (UG909).
- Bitstream compression, which is enabled by default for
Tandem Configuration solutions, is not compatible with the Dynamic Function eXchange
per-frame CRC feature. If per-frame CRC checking is desired for any of the “update”
partial bitstreams, rerun bitstream generation with that feature enabled and bitstream
compression disabled. The
write_bitstream -cell option can be used to
create only the partial and clearing bitstreams needed for each design image.