Low Area Mode - Low Area Mode - 1.0 English - PG247

When all of the endpoint slaves connected to the MI-side of the SmartConnect are 32-bit-wide AXI4-Lite slaves, the SmartConnect Hierarchical IP automatically uses Low Area Mode to optimize for Area at the expense of performance. If any of the masters connected to the SI-side of the SmartConnect are AXI4 or AXI3 masters, then in-bound multi-beat burst transactions are automatically converted into a sequence of single-beat transactions for AXI4-Lite slaves. Null WSTRB beats are suppressed, as described in Conversion to AXI4-Lite.

In Low-Area Mode, internal FIFO buffering is eliminated and the IP propagates a single outstanding write and read transaction at a time. Also, the conditional register slices that are normally present, by default, on each SI and MI interface are disabled.

When an instance of SmartConnect uses Low Area Mode, the following message is issued to the Vivado log file during Validation:

"INFO: [xilinx.com:ip:smartconnect:1.0-1] ... SmartConnect instancename is in Low-Area Mode." 

Otherwise, the following message is issued to the Vivado log:

"INFO: [xilinx.com:ip:smartconnect:1.0-1] ... SmartConnect instancename is in High-performance Mode." 

Beginning in Vivado 2026.1, SmartConnect supports two alternative implementations of Low Area Mode. The Ultralite new mode offers significant area reduction for qualifying configurations of SmartConnect. Ultralite is qualified, and is automatically used, when all of the following restrictions are satisfied:

1. None the MI or SI interfaces are cascaded.
2. No more than 64 total address apertures. (This is the number of aligned power-of-2 apertures after decomposing any non-power-of-2 address segments expressed in the Address Editor.)
3. All AXI4-Lite interfaces must be 32 bits wide.
4. SmartConnect Advanced Property "enable_exclusive_access" must not be enabled.
5. The address map, as it relates to pathways passing through the SmartConnect instance, must not specify any sparse connectivity. That is, there must be no variations among all SI in the way they access the MI, either in terms of connectivity or the target address range.

When an instance of SmartConnect is using Ultralite Mode, the following message is issued to the Vivado log file during Validation:

"INFO: [xilinx.com:ip:smartconnect:1.0-1] ... SmartConnect instancename is in Ultralite Mode." 

You can force SmartConnect to use legacy Low Area Mode by specifying the following Advanced Property:

CONFIG.ADVANCED_PROPERTIES {__experimental_features__ {legacy_low_area_mode 1}}

When you migrate designs from a Vivado release earlier than 2026.1, Vivado automatically adds the above property your SmartConnect instance to prevent your functionality from changing. To take advantage of Ultralite mode, you can delete the property (or change its value to 0).