Visible to Intel only — GUID: iga1401317114353
Ixiasoft
Visible to Intel only — GUID: iga1401317114353
Ixiasoft
12.2.4. Host-Target Connection
Below you can see the connection between a host PC and an Platform Designer-generated system containing a JTAG UART core.
The JTAG controller on the FPGA and the download cable driver on the host PC implement a simple data-link layer between host and target. All JTAG nodes inside the FPGA are multiplexed through the single JTAG connection. JTAG server software on the host PC controls and decodes the JTAG data stream, and maintains distinct connections with nodes inside the FPGA.
The example system in the figure above contains one JTAG UART core and a Nios® II processor. Both agents communicate with the host PC over a single Intel FPGA download cable. Thanks to the JTAG server software, each host application has an independent connection to the target. Intel provides the JTAG server drivers and host software required to communicate with the JTAG UART core.
Systems with multiple JTAG UART cores are possible, and all cores communicate via the same JTAG interface. To maintain coherent data streams, only one processor should communicate with each JTAG UART core.