modeling external memory
you can model external memory using features from vision hdl toolbox™ support package for xilinx® zynq®-based hardware or soc blockset™. both products provide models for a frame buffer or a random access interface. they both also map your subsystem ports to physical axi memory interfaces when you generate hdl code and target a prototype board.
vision hdl toolbox support package for xilinx zynq-based hardware provides a simple model of the memory interface. it does not model the timing of the interface. this level of modeling assists with targeting a memory interface on hardware, but behavior can differ between the simulation and the hardware. for more information, see (vision hdl toolbox support package for xilinx zynq-based hardware).
soc blockset provides library blocks to model a memory controller and multiple memory channels. this model calculates and visualizes memory bandwidth, burst counts, and transaction latencies in simulation. you can also model memory accesses from a processor as part of hardware-software co-design. use the soc builder app to generate code for fpga and processor designs and load and run the design on a board. you can also deploy an axi memory interconnect monitor on your fpga, which can return memory transaction information for debugging and visualization in simulink®. this level of modeling helps you verify throughput and latency requirements and enables modeling of multiple memory consumers, including processor memory access. for more information, see memory (soc blockset).
frame buffer
vision hdl toolbox support package for xilinx zynq-based hardware | soc blockset |
---|---|
this figure shows part of the (vision hdl toolbox support package for xilinx zynq-based hardware) example. the video frame buffer block accepts and
returns the pixel streaming interface used by vision hdl toolbox blocks. it reads and returns an entire frame when you
set the pop signal to | this figure shows part of the (soc blockset) example.
the example shows how to use the memory channel and
memory controller library blocks to model a frame
buffer and additional memory consumers. you can use this model to
confirm that the memory interface meets the throughput and latency
requirements of your design. you can measure the bandwidth and
transaction latency for each memory consumer and check the
measurements against the total bandwidth available from the memory.
to model a frame buffer that supports the pixel streaming interface
used by vision hdl toolbox blocks, configure the channel
type parameter of the memory channel
block as |
random access
vision hdl toolbox support package for xilinx zynq-based hardware | soc blockset |
---|---|
this figure shows part of the (vision hdl toolbox support package for xilinx zynq-based hardware) example. the external memory block reads and writes to any address in the memory. in this case, rather than connecting the pixel stream to the memory interface, your custom fpga logic must generate read and write transactions with specific addresses. to use this block in your designs, copy it from the example model. | this figure shows part of the (soc blockset) example. this design uses a memory controller and two memory channel blocks to implement a random-access interface. in this case, rather than connecting the pixel stream to the memory interface, your custom fpga logic must generate read and write transactions with specific addresses. |
see also
(vision hdl toolbox support package for xilinx zynq-based hardware) | memory (soc blockset)