Constructor Parameters - Constructor Parameters - 2026.1 English - UG1864

Parameter	Type	Default	Description
w_user	int	0	Bit width of the USER sideband channel. Set to 0 to disable.
w_id	int	0	Bit width of the ID sideband channel. Set to 0 to disable.
w_dest	int	0	Bit width of the DEST sideband channel. Set to 0 to disable.
enable_tdata	bool	True	Enable the TDATA channel. When False, payload data is carried through TUSER, and TKEEP/TSTRB are automatically disabled.
enable_tkeep	bool	True	Enable the TKEEP sideband field.
enable_tlast	bool	True	Enable the TLAST sideband field.
enable_tstrb	bool	True	Enable the TSTRB sideband field.
strict	bool	False	Match kernels that require disabled sideband fields to be absent from the AXI4-Stream transfer.

Choose these values to match the AXI4-Stream port used by your HLS kernel.

enable_tdata=False. Use this value when the kernel carries data through TUSER instead of TDATA. TKEEP and TSTRB are automatically disabled because they describe TDATA byte validity. You still provide a dtype and an input array so VFS knows how many transfers to run.

strict versus non-strict. Set strict to match the HLS kernel declaration. This setting affects how disabled sideband fields are represented in the AXI4-Stream transfer. It does not change which fields are available on the varray. For example, arr.tlast is unavailable whenever enable_tlast=False.