Reads from RXFIFO

Zynq UltraScale+ Device Technical Reference Manual (UG1085)

Document ID
UG1085
Release Date
2022-09-15
Revision
2.3 English

All 16 bytes must be read from the RXFIFO to receive the complete message.

The first word read (4 bytes) returns the identifier of the received message RXFIFO_DLC register.

The second read returns the 16-bit receive time stamp and data length code [DLC] field of the received message RXFIFO_DLC register.

The third read returns data word 1 RXFIFO_DATA1 register.

The fourth read returns data word 2 RXFIFO_DATA2 register.

A free running 16-bit counter provides a time stamp relative to the time the message was successfully received.

All four words must be read for each message, even if the message contains less than eight data bytes. Write transactions to the RXFIFO are ignored. Reads from an empty RXFIFO return invalid data and generates an RX underflow interrupt.