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Read and write memory locations on FPGA board from MATLAB


The aximaster object communicates with the MATLAB® AXI master IP when it is running on an FPGA board. The object forwards read and write commands to the IP to access slave memory locations on the FPGA board. Before using this object, follow the steps in Set Up MATLAB as AXI Master.



mem = aximaster(vendor) returns an object, that controls an AXI4 master IP for the FPGA that is running on your board. vendor specifies the FPGA brand name. This connection enables you to access memory locations in an SoC design from MATLAB.

mem = aximaster(vendor,Name,Value) sets properties using one or more name-value pair arguments. Enclose each property name and value in quotes. For example, 'DeviceAddress','' specifies the internet protocol (IP) address of the FPGA board as

Input Arguments

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FPGA brand name, specified as 'Intel' or 'Xilinx'. This value specifies the manufacturer of the FPGA board. The AXI master IP varies depending on the type of FPGA that you specify.


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Type of interface used for communication with the FPGA board, specified as 'JTAG' (default), 'PCIe', or 'UDP'. This value specifies the interface type for communicating between the host and the FPGA.

Name of the JTAG cable used for communication with the FPGA board, specified as a character vector or string scalar representing a JTAG cable name. Specify this property if more than one JTAG cable of the same type are connected to the host computer. If the host computer has more than one JTAG cable and you do not specify this property, the object returns an error. The error message contains the names of the available JTAG cables. For more details, see Select from Multiple JTAG Cables.

Data Types: char | string

Internet protocol (IP) address of the Ethernet port on the FPGA board, specified as a character vector or string scalar representing an IP address.

Example: ''


To enable this property, set the Interface to 'UDP'.

Data Types: char | string

Type of target device, specified as, 'FPGA' (default) or 'SoC'. When you are using a Xilinx Zynq or an Intel SoC as a target device, specify this property as 'SoC'.

Example: 'SoC'

User datagram protocol (UDP) port number of the target FPGA board, specified as an integer.

Example: '12345'


To enable this property, set the Interface property to 'UDP' and the DeviceType property to 'FPGA'.

Data Types: uint16

Object Functions

readmemoryRead data out of AXI4 memory-mapped slaves
releaseRelease JTAG or Ethernet cable resource
writememoryWrite data to AXI4 memory-mapped slaves


Access Memory on FPGA Board from MATLAB

Before you can use this object, you must have a design running on an FPGA board connected to the MATLAB host machine. The FPGA design must include an AXI master IP that is customized for your FPGA vendor. This IP is included with the support package installation. To include the IP in your project, see Access FPGA External Memory Using MATLAB as AXI Master.

Create a MATLAB AXI master object. The object connects with the FPGA board and confirms that the IP is present.

mem = aximaster('Intel')
mem = 

  aximaster with properties:

           Vendor: 'Intel'
    JTAGCableName: 'auto'

Write and read one or more addresses with one command. By default, the commands auto-increment the address for each word of data. For example, this code writes ten addresses and then reads from a single location.

rd_d = readmemory(mem,140,1)
rd_d =



Now, read from ten locations.

rd_d = readmemory(mem,140,10)
rd_d =

  1×10 uint32 row vector

   10   11   12   13   14   15   16   17   18   19

Set the BurstType property to 'Fixed' to turn off the auto-increment and access the same address multiple times. For example, this code reads ten times from the same address.

rd_d = readmemory(mem,140,10,'BurstType','Fixed')
rd_d =

  1×10 uint32 row vector

   10   10   10   10   10   10   10   10   10   10

Write ten times to the same address. In this case, the final value stored in address 140 is 29.

rd_d = readmemory(mem,140,10)
rd_d =

  1×10 uint32 row vector

   29   11   12   13   14   15   16   17   18   19

Alternatively, specify the address as a hexadecimal string. To cast the read data to a data type other than uint32, use the OutputDataType property.

rd_d = readmemory(mem,0x1c,16,'OutputDataType',numerictype(0,6,4))
rd_d = 

  Columns 1 through 10
         0    0.2500    0.5000    0.7500    1.0000    1.2500    1.5000    1.7500    2.0000    2.2500
  Columns 11 through 16
    2.5000    2.7500    3.0000    3.2500    3.5000    3.7500

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Unsigned
            WordLength: 6
        FractionLength: 4

When you no longer need to access the board, release the JTAG connection.


Select from Multiple JTAG Cables

If two cables of the same type are connected to your host computer, specify the JTAGCableName property identifier for the board where the JTAG master IP is running. To see the JTAG cable identifiers, attempt to create an aximaster object. The object returns a list of the current JTAG cable names.

h = aximaster('Intel')
Error using fpgadebug_mex
Found more than one JTAG cable:
0 (Max10): #tpt_0001#ptc_0002#210203991642
1 (Arria): #tpt_0001#ptc_0002#210319789795
Please disconnect the extra cable, or specify the cable name as an input argument.
See documentation of FPGA Data Capture or MATLAB as AXI master to learn how to set
the cable name.

To communicate with the Arria board, specify the matching JTAG cable name.

h = aximaster('Intel','JTAGCableName','#tpt_0001#ptc_0002#210319789795')
Introduced in R2017a