Intel® Quartus® Prime Pro Edition User Guide: Platform Designer

ID 683609
Date 10/04/2021
Public

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6.11.4. Almost-Full and Almost-Empty Thresholds to Prevent Overflow and Underflow

You can use almost-full and almost-empty thresholds as a mechanism to prevent FIFO IP overflow and underflow. This feature is available only in the Avalon® Streaming Single-Clock FIFO IP. To use the thresholds, turn on the Use fill level, Use almost-full status, and Use almost-empty status parameters. You can access the almost_full_threshold and almost_empty_threshold registers via the csr interface and set the registers to an optimal value for your application.

You can obtain the almost-full and almost-empty statuses from almost_full and almost_empty interfaces ( Avalon® streaming status source). The IP asserts the almost_full signal when the fill level is equal to or higher than the almost-full threshold. Likewise, the IP asserts the almost_empty signal when the fill level is equal to or lower than the almost-empty threshold.