User guide

System Generator for DSP User Guide www.xilinx.com 245
UG640 (v 12.2) July 23, 2010
Shared Memory Support
Viewing Shared Memory Information
Hardware co-simulation blocks allow you to view information about the shared memories
that were compiled as part of the design. A hardware co-simulation block that contains
shared memories will have an enabled Shared Memories tab in the block configuration
dialog box shown below. Clicking on this tab exposes a table of information about each
shared memory in the design.
The shared memory information table describes the type, bit width, and depth of each
shared memory in the design. For Shared Memory blocks, it also specifies the Access
Protection mode. Clicking on the [+] or [-] symbol next to the shared memory icon expands
or collapses the shared memory table, respectively.
The icons associated with each shared memory type are shown in the table below.
Co-Simulating Unprotected Shared Memories
Unprotected shared memory blocks may be written to or read from at any time – this type
of memory has no notion of mutually exclusive access. Data transfers to and from an
unprotected hardware shared memory occur a single-word at a time, unlike the high-
speed data transfer mode used by lockable shared memories. To ensure data coherency
between software and hardware, a single image of the shared memory data is shared
between hardware and software. This image is stored in the FPGA using dual port
memory. System Generator allows both hardware design logic and other software-based
shared memory objects on the host PC to access the shared memory data concurrently.
Memory Type Icon
Shared Memory
Shared FIFO
Shared Register