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AR# 35435

11.1 EDK, XPS_MCH_EMC - Write-to-write flash timing violated


When using the xps_mch_emc core, the spacing between writes is too short, violating the back-to-back write timing specifications (tWPH).

This issue potentially affects flash devices when the xps_mch_emc is configured to use data width matching, and software performs accesses wider than the aggregate data width of all flash devices used. For example, a 32-bit access to a 16-bit flash will cause data width matching.


A patch is available to guard against violating tWPH. It can be downloaded from:


The patch adds an additional timing parameter for each memory bank: C_TWPH_PS_MEM_0, C_TWPH_PS_MEM_1, C_TWPH_PS_MEM_2, and C_TWPH_PS_MEM_3.


1. Extract the archive to a temporary folder.
2. Copy the contents of the archive to the <Project>\pcores folder.
3. Restart XPS.

Update the C_TWPH_PS_MEM_x parameter in the MHS for the associated memory. C_TWPH_PS_MEM_x defines the delay between writes in picoseconds (ps). Rebuild the netlist.

The XPS_MCH_EMC core is currently not planned to be updated with this enhancement.

Linked Answer Records

Master Answer Records

Answer Number Answer Title Version Found Version Resolved
34609 12.x EDK - Master Answer Record List N/A N/A
AR# 35435
Date Created 04/28/2010
Last Updated 12/15/2012
Status Active
Type General Article
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