12-12-2012, 04:13 PM
FIFO Depth Calculation .
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Basically we use FIFO for synchronizing two clock domains (different frequencies) so we need a device which has some tolerance power to hold the data that device is called FIFO .By using FIFO we can easily avoid overflow and underflow conditions The scenario can be two of following
• Writing is faster than reading then there is possibility of overflow
• Writing is slower than reading then there is possibility of underflow
In FIFO depth calculation we always have to consider worst cast .size of FIFO basically implies that how much data is required to buffer . And it is totally depend on data rate of reading and writing.
Data rate = Number of Data x Time Period
Difference = DRFAST – DRSLOW
Depth = Difference / Higher Freq. Time Period
Writing side is Source and Reading Side is Sink. If the data rate of writing is higher then the reading side’s data rate then the FIFO will now overflow.Another Type of depth calculation can be done by this method.