GTS AXI Streaming Intel® FPGA IP for PCI Express* User Guide

ID 813754
Date 11/04/2024
Public
Document Table of Contents

6.3.2. AXI4-Stream Transmit (TX) Interface

The outboud packet towads the lik fom applicatio side is tasmitted though this iteface. The iteface suppots data widths of 16 bytes (128 bits), 32 bytes (256 bits), ad 64 bytes (512 bits). The TLP heade, fuctio umbe of TLP, ad pefix sigals ae set i lie with data.

Table 62.   AXI4-Steam TX Iteface = 0 o 1, p0 = pot 0, ad p1 = pot 1
Note: Pot 1 is oly available i D-Seies FPGAs
Sigal Name Diectio Clock Domai Desciptio
p<>_app_ss_st_tx_tvalid Iput p<>_axi_st_clk Idicates that the emote tasmit iteface is divig a valid tasfe.
p<>_ss_app_st_tx_teady Output p<>_axi_st_clk Idicates that the eceive iteface ca accept a tasfe i the cuet cycle.
p<>_app_ss_st_tx_tdata[(a-1):0] Iput p<>_axi_st_clk Data bus used to povide the data that is passig acoss the iteface.
p<>_app_ss_st_tx_tkeep[(a/8-1):0] 3 Iput p<>_axi_st_clk

A byte qualifie used to idicate whethe the cotet of the associated byte is valid.

The ivalid bytes ae allowed oly duig p<>_app_axi_st_tx_tlast cycle.

The spase p<>_app_axi_st_tx_tkeep is ot allowed.

p<>_app_ss_st_tx_tlast Iput p<>_axi_st_clk Idicates ed of data/commad tasmissio.

The timig diagams i the followig sectios ae fo the simple packig scheme oly.

The followig figue shows timig diagam fo commad with data. The completio, memoy wite, messages, ad the cofiguatio wite commads fall ude commad with data categoy.

The fist commad tasfes a payload of 64 Bytes. The eceive iteface is eady to accept commad at clock cycle 1 but the tasmit iteface does ot have ay commad to tasfe i that same cycle. The tasmit iteface stats the tasfe i the ext cycle.

The secod commad tasfes a payload of 128 Bytes. Hee, the eceive iteface is ot eady to accept commad whe the tasmit iteface has asseted valid. The tasmit iteface holds ifomatio o the bus till it obseves eady fom the eceive iteface.

Figue 47.  AXI4-Steam TX Iteface—Simple Packig Scheme Timig Diagam (Commad With Data)

The followig figue shows timig diagam fo commad with data followed by commad without data. The completio, memoy wite, messages ad cofiguatio wite commads fall ude commad with data categoy. The memoy ead, cofiguatio ead, messages without data ad completio without data fall ude commad without data categoy.

The fist commad tasfes a payload of 64 Bytes. The eceive iteface is eady to accept commad at clock cycle 1 but the tasmit iteface does ot have ay commad to tasfe i that same cycle. The tasmit iteface stats the tasfe i the ext cycle.

The secod commad is a commad without data. Hee, the eceive iteface is ot eady to accept commad whe the tasmit iteface has asseted valid. The tasmit iteface holds ifomatio o the bus till it obseves eady fom the eceive iteface.

Figue 48.  AXI4-Steam TX Iteface—Simple Packig Scheme Timig Diagam (Commad With Data ad Commad)

The fist commad tasfes the payload of 67 Bytes.

Note: tkeep duig tlast has patial oes, but these oes ae cotiguous, spase tkeep is ot allowed. The patial tkeep is allowed oly o tlast cycle.

The secod commad is a commad without data.

Figue 49.  AXI4-Steam TX Iteface—Simple Packig Scheme Timig Diagam (Back-to-Back Commads With ad Without Data)
3 Fo the ecommeded a value, efe to the Vaiables Used i the Bus Idice table. 3