Xilinx V2.1 - Manual (Page 104)

104 Xilinx Development System
Xilinx System Generator v2.1 Reference Guide
Virtex, Virtex-E and Spartan-II families support only Read After Write. Virtex-II
supports all modes.
Block Parameters Dialog Box
The block parameters dialog box can be invoked by double-clicking the icon in your
Simulink model.
Figure 3-71: Dual Port RAM block parameters dialog box
Parameters specific to the block are:
•
Depth : specifies the number of words in the memory for Port A, which must be a
positive integer. The Port B depth is inferrred from the form factor specified by
the input data widths.
•
Initial Value Vector : specifies the initial memory contents. The size and
precision of the elements of the initial value vector are based on the data format
specified for Port A. When the vector is longer than the RAM, the vector’s trailing
elements are discarded. When the RAM is longer than the vector, the RAM’s
trailing words are set to zero.
•
Zero Initial Output : when checked, the data out ports have value of zero at
clock 0; otherwise, the ports have a value of NaN (not a number).
•
Write Mode (A/B Ports) : specifies the memory behavior to be Read Before
Write, Read After Write, or No Read On Write. There are device specific
restrictions on the applicability of these modes.
Other parameters used by this block are explained in the Common Parameters section
of the previous chapter of the Reference Guide.