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AR# 31917

LogiCORE DVB S2 FEC Encoder v1.4 - Why does the newer version use more block RAM than the previous version; therefore, I now receive an overmapped error after updating the design?


Keywords: memory, resource, MAP

The LogiCORE DVB S2 FEC Encoder v1.3 of the core works fine on my design. After I upgrade the core to v1.4, it now uses more block RAM and, for certain devices, I am now receiving the following error message during MAP:

"Number of RAMB16s: 26 out of 24 108% (OVERMAPPED)
ERROR:Pack:2310 - Too many comps of type "RAMB16" found to fit this device."


To reduce power and logic resource, the LogiCORE DVB S2 FEC Encoder v1.4 uses more block RAM. For example, in the previous version of the core 24 block RAM was used, whereas, in the v1.4 core 26 block RAM are used. The logic resources, however, are greatly reduced. Even though the block RAM utilization is stated in the datasheet, the user needs to be aware of this before selecting a specific device; as in some devices, the number of block RAM could be a limiting factor.

However, if a device has been selected and the increase in block RAM is causing an issue, please contact Xilinx Support.
AR# 31917
Date 11/17/2008
Status Active
Type General Article
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