RapidIO Intel FPGA IP User Guide

ID 683884
Date 9/15/2021
Public
Document Table of Contents

4.5.2.4.1. Port-Write Transmission

To send a port-write to a remote device, you must program the transmit port-write control and data registers. These registers are accessed using the System Maintenance Avalon® -MM slave interface. The following header fields are supplied by the values stored at the Tx Port Write Control register:
  • DESTINATION_ID
  • priority
  • wrsize

The other fields of the MAINTENANCE port-write packet are assigned as follows. The ftype is assigned a value of 4'b1000 and the ttype field is assigned a value of 4'b0100. The wdptr and wrsize fields of the transmitted packet are calculated from the size of the payload to be sent as defined by the size field of the Tx Port Write Control register. The source_tid and config_offset are reserved and set to zero.

The payload is written to a Tx Port Write Buffer starting at address 0x10210. This buffer can store a maximum of 64 bytes. The port-write processor starts the packet composition and transmission process after the PACKET_READY bit in the Tx Port Write Control register is set. The composed Maintenance port-write packet is sent to the Transport layer for transmission.