Quartus® Prime Pro Edition User Guide: Platform Designer

ID 683609
Date 7/07/2025
Public
Document Table of Contents

6.12.2. Avalon® Streaming FIFO IP Operating Modes

  • Default mode—the IP accepts incoming data on the in interface ( Avalon® streaming data sink) and forwards it to the out interface ( Avalon® streaming data source). The IP asserts the valid signal on the Avalon® streaming source interface to indicate that data is available at the interface.
  • Store and forward mode—this mode applies only to the single-clock FIFO IP. The IP asserts the valid signal on the out interface only when a full packet of data is available at the interface. In this mode, you can also enable the drop-on-error feature by setting the drop_on_error register to 1. When this feature is enabled, the IP drops all packets received with the in_error signal asserted.
  • Cut-through mode—this mode applies only to the single-clock FIFO IP. The IP asserts the valid signal on the out interface to indicate that data is available for consumption when the number of entries specified in the cut_through_threshold register are available in the FIFO buffer.
Note: To use the Store and Forward or Cut-through mode, set the following:
  • Turn on the Use store and forward parameter to include the CSR interface ( Avalon® memory-mapped interface agent).
  • Set the cut_through_threshold register to 0 to enable the Store and Forward mode. Set the register to any value greater than 0 to enable the Cut-through mode. The non-zero value specifies the minimum number of FIFO entries that must be available before the data is ready for consumption. Setting the register to 1 provides the default mode.