10.4.8.1 Synchronous FIFO for IGLOO®, ProASIC® 3, SmartFusion® and Fusion Functionality

Using ESTOP and FSTOP

The ESTOP pin is used to stop the read counter from counting any further once the FIFO is empty (that is the EMPTY flag goes high). Likewise, the FSTOP pin is used to stop the write counter from counting any further once the FIFO is full (that is the FULL flag goes high). These are configuration pins that should not be dynamically reconfigured. The software configures these signals based on your selection.

The FIFO counters in ProASIC3E start the count from 0, reach the maximum depth for the configuration (for example 511 for a 512X9 configuration), and then re-start from 0. A potential application for the ESTOP, where the read counter keeps counting would be, writing to the FIFO once and reading the same content over and over, without doing a write again.

A typical user would not need to use these features and should leave these options un-checked in the GUI.