Visible to Intel only — GUID: lzj1697092308168
Ixiasoft
Visible to Intel only — GUID: lzj1697092308168
Ixiasoft
7.3.2. AXI4-Stream Transmit (TX) Interface
The outbound packet towards the link from application side is transmitted through this interface. The interface supports data widths of 16 bytes (128 bits), 32 bytes (256 bits), and 64 bytes (512 bits). The TLP header, function number of TLP, and prefix signals are sent in line with data.
Signal Name | Direction | Clock Domain | Description |
---|---|---|---|
p<n>_app_ss_st_tx_tvalid | Input | p<n>_axi_st_clk | Indicates that the remote transmit interface is driving a valid transfer. |
p<n>_ss_app_st_tx_tready | Output | p<n>_axi_st_clk | Indicates that the receive interface can accept a transfer in the current cycle. |
p<n>_app_ss_st_tx_tdata[(a-1):0] | Input | p<n>_axi_st_clk | Data bus used to provide the data that is passing across the interface. |
p<n>_app_ss_st_tx_tkeep[(a/8-1):0] 2 | Input | p<n>_axi_st_clk | A byte qualifier used to indicate whether the content of the associated byte is valid. The invalid bytes are allowed only during p<n>_app_axi_st_tx_tlast cycle. The sparse p<n>_app_axi_st_tx_tkeep is not allowed. |
p<n>_app_ss_st_tx_tlast | Input | p<n>_axi_st_clk | Indicates end of data/command transmission. |
The timing diagrams in the following sections are for the simple packing scheme only.
The following figure shows timing diagram for command with data. The completion, memory write, messages, and the configuration write commands fall under command with data category.
The first command transfers a payload of 64 Bytes. The receive interface is ready to accept command at clock cycle 1 but the transmit interface does not have any command to transfer in that same cycle. The transmit interface starts the transfer in the next cycle.
The second command transfers a payload of 128 Bytes. Here, the receive interface is not ready to accept command when the transmit interface has asserted valid. The transmit interface holds information on the bus till it observes ready from the receive interface.
The following figure shows timing diagram for command with data followed by command without data. The completion, memory write, messages and configuration write commands fall under command with data category. The memory read, configuration read, messages without data and completion without data fall under command without data category.
The first command transfers a payload of 64 Bytes. The receive interface is ready to accept command at clock cycle 1 but the transmit interface does not have any command to transfer in that same cycle. The transmit interface starts the transfer in the next cycle.
The second command is a command without data. Here, the receive interface is not ready to accept command when the transmit interface has asserted valid. The transmit interface holds information on the bus till it observes ready from the receive interface.
The first command transfers the payload of 67 Bytes.
The second command is a command without data.