Receive Data FIFO Occupancy Register (RDFO) - 4.3 English - PG080

AXI4-Stream FIFO LogiCORE IP Product Guide (PG080)
Document ID
PG080
Release Date
2023-11-08
Version
4.3 English

The Receive Data FIFO Occupancy Register shown in is a read-only register that gives the occupancy status of the Receive Data FIFO.

Figure 1. Receive Data FIFO Occupancy Register (Offset 0x1C)
Table 1. Receive Data FIFO Occupancy Register Bit Definitions
Bit(s) Name Core Access Reset Value Description
16:0 Occupancy Read 0x0

Receive Data FIFO Occupancy: This is the unsigned value reflecting a current snapshot of the number of locations in use for data storage in the receive Data FIFO memory core in the most recent transaction. This value is only updated after a packet is successfully received, and therefore can be used to determine if a receive packet is ready to be processed when a non-0 value is read.

If the number of packets received is one, then this register returns the value of the locations occupied. After the FIFO is read, any subsequent read to this register returns the value of 0. If more than one packet is received, a read to this register returns the number of locations occupied by the latest received packet.
31:17 Reserved Read 0x0 Reserved: These bits are reserved for future definition and always return all zeros.