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First use of the Zynq-7000 Programmable Logic on a Zynq Board

Posted by Florent - 23 September 2016

 

Introduction

In this tutorial, we will configure (i.e. program) the Programmable Logic (PL) part of a Zynq-7000 of a Zynq Board. For this tutorial we will use a Xilinx ZC702 board but this could also been done on another board with a Xilinx 7series FPGA. The equivalences to try it on a ZedBoard or on a ZYBO are given (but not checked).

Control LEDs from the switches

In this part we will create a Vivado RTL project which will control some LEDs of the Xilinx ZC702 board using switches.

Add the Board File to Vivado

If you are using a Xilinx ZC702 board or a Digilent ZedBoard, you shouldn’t need to do this step (the board should appear in the Boards List when selecting the default part).

If you are using a ZYBO, a zedboard, a basys3 or a nexys4, download the Board File from the digilent website (here). Unzip the folder and copy the folder: <zip_exracted_location>\vivado-boards-master\new\board_files\<board_name> in C:\Xilinx\Vivado\<version>\data\boards\boards_files.

Create a new project

Open Vivado and create a new RTL project. In the “Default Part” window, select the “ZYNQ-7 ZC702 Evaluation Board” (or the board you are using if other)

Xilinx Vivado - Board choice

Figure 1 - Board choice in the “Default Part” window

Create the VHDL file

Create a new VHDL file (top_level.vhd). In the “Define Module” window, add to inputs (SW1_inp, SW2_inp) and two outputs (LED1_outp, LED2_outp).

Xilinx Vivado - “Define Module” window

Figure 2 - “Define Module” window

Open the VHDL file in the Vivado text editor and simply write the VHDL code to connect the SW1_inp to LED1_outp and SW2_inp to LED2_outp as shown in the Figure 3.

Xilinx Vivado - Connect signals

Figure 3 - Connect the signals

Then click on “Run Synthesis” in the “Flow Navigator”.

Create the physical constraints

We will have to tell Vivado which pin of the device corresponds to which input/output. For the two input signals, we will use the two little switches from the switch SW12 of the Xilinx ZC702 (or the switches SW0 and SW1 on the ZedBoard/ZYBO).

ZC702 - GPIO DIP Switches

Figure 4 - GPIO DIP Switches (source: Xilinx UG850)

In the Figure 4 (from the Xilinx UG850) we can see that the two switches are connected to the pins W6 and W7 of the Zynq device on the board (from the ZYBO reference manual (https://reference.digilentinc.com/reference/programmable-logic/zybo/reference-manual), SW0 and SW1 are connected to G15 and P15 and from the ZedBoard User Guide (http://zedboard.org/sites/default/files/documentations/ZedBoard_HW_UG_v2_2.pdf), SW0 and SW1 are connected to F22 and G22).

SW12, DS19 and DS20 on the Xilinx ZC702 board

Figure 5 - SW12, DS19 and DS20 on the Xilinx ZC702 board

For the two inputs, we will use the user LEDs DS19 and DS20 (LD0 and LD1 for the ZYBO/ZedBoard). In the Figure 5 (from the Xilinx UG850) we can see that the two LEDs are connected to the pins E15 and D15 of the Zynq device on the board (M14 and M15 for the ZYBO, T22 and T21 for the ZedBoard).

ZC702 - User LED Connections

Figure 6 - User LED Connections (source: Xilinx UG850)

When the synthesis is finished click on “Open the synthesized design” on the “Synthesis completed” window (can also be opened from the Flow Navigator). You should have the “package” windows opened as shown in the Figure 7. If not, make sure the layout is “I/O planning” (also shown in the Figure 7) or click on “layout > I/O planning” from the menu.

Xilinx Vivado - Package window

Figure 7 - Package window

Create a new constraints file by clicking on “Add Sources” in the “Flow Navigator” and the selecting “Add Or Create constraints” in the “Add Sources” window. Name the file phys_const.

Xilinx Vivado - Create constraints file

Figure 8 - Create constraints file

In the “I/O Ports” window, in the Package Pin columns enter E15 (M14 for ZYBO, T22 for ZedBoard) for LED1_outp, D15 (M15 for ZYBO, T21 for ZedBoard) for LED2_outp, W6 (G15 for ZYBO, F22 for ZedBoard) for SW1_inp and W7 (P15 for ZYBO, G22 for ZedBoard) for SW2_inp.

Xilinx Vivado - I/O ports constraints

Figure 9 - I/O ports constraints

Enter LVCMOS25 in the column “I/O Std” for all the lines (LVCMOS33 for LED1_outp and LED2_outp on the Zedboard). Press Ctrl+S to save the constraints. If an “Out of Date Design” window appears, just click OK. Then a “Save Constraints” window should appear. Select “Select an existing file” and the constraints file we have created and click OK.

Xilinx Vivado - “Save Constraints” window

Figure 10 - “Save Constraints” window

If we open the file phys_const.xdc (from the Sources window), we can see that Vivado has saved in this file the constraints we have entered in the I/O ports window.

File phys_const.xdc

Figure 11 - File phys_const.xdc

 

Generate the Bitstream and program the FPGA

Click on “Run Implementation” in the “Flow Navigator”. When the implementation is completed, click on “Generate Bitstream”.

Xilinx Vivado - Implementation Completed

Figure 12 - Implementation Completed

When the Bitstream Generation is completed, click on “Open Hardware Manager”.

Xilinx Vivado - Bitstream Generation Completed

Figure 13 - Bitstream Generation Completed

Power on the board and make sure the board is connected to the PC (and you are not using a Virtual Machine). Click on “Open Target > Open New Target…”. Choose Local Server in the “Hardware Server Setting”.

Xilinx Vivado - Open New Target

Figure 14 - Open New Target

The tool should find your device as shown in the Figure 15.

Xilinx Vivado - Open New Hardware Target

Figure 15 - Open New Hardware Target

Then click on “Program Device” to program the FPGA.

Test on the board

On the board you should have two LEDs INIT and DONE. This two LEDs will indicate you if the configuration of the FPGA went well.  If the INIT led is red, FPGA initialization is in progress and if it is green, FPGA initialization was successful. The DONE LED should be green if the FPGA have been configured successfully.

ZC702 - INIT and DONE status LEDs

Figure 16 - INIT and DONE status LEDs

If the FPGA has been successfully programmed, the LEDs DS19 and DS20 value should change when we change the value of the switches of SW12.



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