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AR# 25363

9.1.01 System Generator for DSP - Why am I not seeing the initialization data come out of a wide RAM/ROM block when the init string requires 54 bits or greater to represent?

Description

Keywords: sysgen, dual port RAM, ROM, double, fixed-point

I have created a memory block which is 128 bits wide and would like to initialize it with the block parameter GUI. However, I am reading out all zeroes when I should be addressing initialized memory.

Solution

The init parameter in the System Generator for DSP memory block GUIs currently supports only the "double" data type. As a result, numbers that require more bits than a double can support, cannot be used to initialize the memory in System Generator.
Possible Workarounds:
1. You can create two or more memories that represent a portion of the full data bus width and use the concat block to combine the smaller buses.

2. Generate the memory in CoreGenerator with the required initialization data in a .COE file and bring the core into System Generator via a black box. For more information on using black boxes in System Generator, see the System Generator black box help and the examples provided with the installation.

This issue will be addressed in a future System Generator release.
AR# 25363
Date Created 06/18/2007
Last Updated 06/18/2007
Status Active
Type General Article