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AR# 16230

LogiCORE SPI-4.2 (POS-PHY L4) v5.0 - Overflown_n is asserted before FFAlmostFull_n is asserted, and data is lost

Description

General Description: I am using a Xilinx SPI-4.2 core, and when I set the following static configuration signals to less than 6, data is lost:

SrcAFThresAssert

SrcAFThresNeg

SnkAFThresAssert

SnkAFThresNeg

In the case above, an Overflow_n flag is asserted before FFAlmostFull_n is true (active Low).

Solution

The "Sink Static Configuration Signals" and "Source Static Configuration Signals" sections of the SPI-4.2 (PL4) Core v5.2 data sheet state that the minimum value for these configuration signals is 4 -- these are data sheet errors. The minimum values for these threshold signals should be:

SrcAFThresAssert = 6

SrcAFThresNeg = 6

SnkAFThresAssert = 6

SnkAFThresNeg =6

The data sheet was corrected to reflect this information in the v5.1 and v5.2 SPI-4.2 update:

http://support.xilinx.com/ipcenter/catalog/logicore/docs/posphyl4_spec.pdf

AR# 16230
Date Created 09/03/2007
Last Updated 05/03/2010
Status Archive
Type General Article