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AXI4 Master Source

Generate random access memory data

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  • AXI4 Master Source block

Libraries:
SoC Blockset / Hardware Logic Testbench

Description

The AXI4 Master Source block generates random access memory data to AXI4-based data interface blocks. You can use this block as a test source block for simulating AXI4-based data applications.

The block accepts a control bus and outputs data along with a control bus.

Examples

Random Access of External Memory

Random Access of External Memory

Model external memory accesses from FPGA for rotating an ASCII art image. Many applications require FPGA to access memory in random fashion as per the requirements of algorithm. You will learn how to design memory address generation along with other AXI4 master signals to read and write specific regions of memory using SoC Blockset. You will simulate, implement and verify your design on hardware.

Ports

Input

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Control bus from the data consumer signaling that data consumer is ready to accept data, specified as a scalar. This control bus comprises these control signals:

  • wr_ready — Indicates the block can send data to the data consumer

  • wr_complete — Indicates the write transaction has completed at the data consumer

  • wr_bvalid — Indicates the data consumer has accepted the transaction

Data Types: WriteControlS2MBusObj

Output

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Output AXI data to the data consumer. This value is returned as a scalar or vector.

You can change the data type of the output data. For more information, see the Data type parameter.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | fixed point

Control bus to the data consumer, returned as a bus. This control bus comprises these control signals:

  • wr_addr — Specifies the starting address that the block writes

  • wr_len — Specifies the number of data elements in the write transaction

  • wr_valid — Indicates the data sampled at the wrData output port is valid

Data Types: WriteControlM2SBusObj

Parameters

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Select the data type format for the output AXI data.

Click the button to display the Data Type Assistant, which helps you to set the data type for the wrData output port. For details, see Specify Data Types Using Data Type Assistant.

Specify the dimensions of the output data as a positive scalar or an array. This value defines the size of the data signal.

Example: 1 specifies a scalar sample.

Example: [10 1] specifies a vector of ten scalars.

Select this parameter to enable data packing across the last dimension of the signal. The Memory Channel block packs the data along the last dimension of the signal. For example, if the channel data type is uint32, the dimensions are [1024 4], and if you select this parameter, then the memory channel generates 1024 read or write transactions of 128 bits. For this example, if you clear this sample packing parameter, the memory channel generates 4096 transactions of 32 bits each.

This figure shows how data is aligned for a signal with data type fixdt10[4x3]. When the data is packed, three 10-bit words are concatenated and extended by 2 bits to a 32-bit sample. When the data is not packed, each 10-bit word is extended to a 16-bit sample.

The top row shows packed data aligned in samples of 10,10,10, and 2 to make 32 bits. The bottom row shows unpacked data aligned in samples of 10 and 6 to make 16 bits.

This figure shows how data is aligned for a signal with data type uint8[8x3]. When the data is packed, three 8-bit words are concatenated and extended by 8 bits to a 32-bit sample. When the data is not packed, each 8-bit word is represented as an 8-bit sample.

The top row shows packed data aligned in samples of 8,8,8, and 8 to make 32 bits. The bottom row shows unpacked data aligned in samples of 8 bits.

The combined width of the flattened signal must not exceed 512 bits.

Specify the number of write requests for the block to send.

Specify the address to which the block writes the data. This value must be a nonnegative integer.

Specify the initial time after which the write operation starts. This value must be a nonnegative scalar.

Specify the generation type for the output as one of these values:

  • counter — Generate data from a counter, based on the selected data type.

  • random — Generate random data.

  • ones — Generate data with all the bits as ones, based on the selected data type.

  • workspace — Generate data from the MATLAB® workspace.

Specify the value from which the counter starts. The valid range of counter values depends on the selected value for the Data type parameter. If this value is out of the valid range, it is rounded off to the nearest valid value.

For example, if Data type is uint8 and this value is 6.787, this value is rounded to 7.

Dependencies

To enable this parameter, set the Data generation parameter to counter.

Specify the workspace variable from which output data is generated. This parameter can be any MATLAB-supported variable name.

Note

The workspace variable must be a numerical array.

Dependencies

To enable this parameter, set the Data generation parameter to workspace.

Specify a time interval in seconds to define how often the block updates.

Specify the Sample time parameter as a scalar when you do not want the output to have a time offset. To add a time offset to the output, specify the Sample time parameter as a 1-by-2 vector where the first element is the sampling period and the second element is the offset. For more information about sample times in Simulink®, see Specify Sample Time.

Version History

Introduced in R2019a

See Also