Functional View – Advanced Properties - Functional View – Advanced Properties - 1.0 English

Snn_Entry Advanced Properties

The following advanced properties can be specified for each S_AXI port enabled on the SmartConnect and connected to an endpoint master IP. Properties that apply specifically to the read or write path are only applicable if the connected endpoint master supports the corresponding access mode. For example, properties specific to the read path are not applicable or available if the connected endpoint master is WRITE_ONLY.

Table 1. Snn_Entry Advanced Properties: CONFIG.ADVANCED_PROPERTIES dictionary keys²:`__view__ functional Snn_Entry`
Name	Description	Format/Range/Dependencies
SUPPORTS_WRAP¹	Supports Wrapped Bursts Configures the SmartConnect entry logic to either accept or reject WRAP transactions from the connected endpoint AXI master. In most cases, AXI SmartConnect automates the value of this parameter based on the interface metadata of the connected master. This parameter can be used to override the automation if, for example, the attached master has not been packaged with sufficient metadata to enable the automation of WRAP support.	Type: Integer Values: 0, 1 Dependencies: Not applicable if the connected master's protocol is AXI4-Lite.
SUPPORTS_DECERR¹	Supports Decode Error Generation Allows some transaction checking features of SmartConnect to be disabled to save area and reduce latency. In most cases, SmartConnect automates this property based on the interface metadata of the connected endpoint master. This parameter can be used to override the automation if the packaging of the attached master does not lead to the preferred automation outcome. When the parameter is set to 0, address range checking and WRAP/FIXED burst detection disables. Address range decoding and checking also disables and all transactions route to the first mapped address segment. One cycle of internal pipelining is also removed. Important: Setting this parameter to 0 prevents the SmartConnect from being able to access multiple MI interfaces and prevents it from generating decode errors if the master issues invalid transactions.	Type: Integer Values: 0, 1 Dependencies: 1: automated
LIM_R_LEN LIM_W_LEN¹	Limit Read Length and Limit Write Length Enables splitting of read or write transactions that exceed the configured length into a series of transactions equal to or less than the configured length. Splitting long write transactions from the master allows you to influence the arbitration behavior of the system or to match a slave's preferred transaction length to allow more efficient processing within the endpoint slave. Avoid reducing the burst lengths to the point that a later width conversion would not have sufficient data beats to fill at least one entire beat of a transaction.	Type: Integer Values: 0, 1, 2, 4, 8, 16, 32, 64, 128, 256 Default: 0 Dependencies: If the interface protocol is AXI3, the range is reduced to powers of 2 up to a maximum of 16. Not applicable if the interface protocol is AXI4-Lite. A value of 0 disables the feature.
PKT_W_THR¹	Packet Write Threshold Specifies the number of write data beats that needs be accepted on the SI and on to the write data FIFO before releasing the corresponding write command. The write command is otherwise released if the last data beat (wlast) is received before the specified threshold. If a master cannot issue write data beats to the SmartConnect in a continuous manner, you can use this to accumulate a continuous sequence of data beats for release to the slave. This can lead to more efficient arbitration and data transfer in the system. Note: Setting this to a positive value does not prevent write data beats from propagating beyond the write data FIFO, if downstream devices are capable of buffering write data before receiving the corresponding write address transfer.	Type: Integer Values: 0, 1, 2, 4, 8, 16, 32, 64, 128, 256 Default: 0 Dependencies: The value of the parameter cannot exceed the write payload buffer depth. The range of the parameter is limited according to the maximum burst length of the interface's AXI protocol. A value of 0 disables the feature.
PKT_R_THR¹	Packet Read Threshold Specifies the maximum occupancy of the read data buffer. If a read command received from the master exceeds the specified value, the command is not released to the slave until sufficient capacity becomes available in the data buffer for the command. The value of the packet threshold cannot exceed the configured read buffer depth for the port. If the master attached to the SmartConnect port does not self-limit the number of read commands it issues, and cannot guarantee all the read data is consumed at the rate it is returned, it is possible that the port's read data buffer fills, leading to a data transfer stall affecting other masters. In this scenario, you can enable the read packet threshold to prevent the master from over-filling its read data buffer and causing such stalls. If the feature is enabled, the read threshold is typically set to the same size as the read data buffer.	Type: Integer Values: 0, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048 Default: 0 Dependencies: The value of the parameter cannot exceed the read payload buffer depth. A value of 0 disables the feature.
This Advanced Property is ignored when SmartConnect is configured in AXI4-Lite Low-Area Mode. 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 uses Low-Area Mode to optimize for Area at the expense of performance. In Low-Area Mode, any in-bound WRAP burst is rejected with DECERR at the SI, and the internal Switchboard data width is 32 bits. For example, the Tcl command to disable the SUPPORTS_WRAP property is similar to: `"set_property -dict [ list CONFIG.ADVANCED_PROPERTIES {__view__ {functional {S00_Entry {SUPPORTS_WRAP 0}}}} ] [get_bd_cells smartconnect_0]"` For more information, refer to Tcl Commands for Advanced Properties.

Table 2. Snn_Buffer and Mnn_Buffer Advanced Properties: `CONFIG.ADVANCED_PROPERTIES dictionary keys: __view__ functional Snn_Buffer`
Name	Description	Format/Range/Dependencies
AR_SIZE AW_SIZE B_SIZE¹	Command and write response buffer size Specifies the depth of the buffer of the associated channel. These buffers are always implemented using distributed RAM FIFOs. Reducing the depth below 32 generally does not result in any reduction of utilization.	Type: Integer Values: 0, 1, 2, 4, 8, 16, 32 Default: 32 Dependencies: N/A
W_SIZE R_SIZE¹	Data Channel Buffer Size Specifies the depth of the data channel buffers. For sizes <512, buffers are implemented using distributed RAM FIFOs. For sizes ≥ 512, buffers are implemented using block RAM. Reducing the depth below 32 generally does not result in any reduction of utilization.	Type: Integer Values: 0, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096 Default: 32
This Advanced Property is ignored when SmartConnect is configured in AXI4-Lite Low-Area Mode. 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 uses Low-Area Mode to optimize for Area at the expense of performance. In Low-Area Mode, any in-bound WRAP burst is rejected with DECERR at the SI, and the internal Switchboard data width is 32 bits.

Table 3. Switchboard Advanced Properties: `CONFIG.ADVANCED_PROPERTIES dictionary keys: __view__ functional SW0`
Name	Description	Format/Range/Dependencies
DATA_WIDTH¹	Switchboard Data Width Specifies the data width in use by the switchboards in the center of the SmartConnect instance.	Type: Integer Values: 32, 64, 128, 256, 512, 1024 Default: Automated
This Advanced Property is ignored when SmartConnect is configured in AXI4-Lite Low-Area Mode. 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 uses Low-Area Mode to optimize for Area at the expense of performance. In Low-Area Mode, any in-bound WRAP burst is rejected with DECERR at the SI, and the internal Switchboard data width is 32 bits.

Functional View – Advanced Properties - Functional View – Advanced Properties - 1.0 English - PG247

SmartConnect LogiCORE IP Product Guide (PG247)

Snn_Entry Advanced Properties