AN 717: Nios II Gen2 Hardware Development Tutorial

ID 683615
Date 9/22/2014
Public
Document Table of Contents

1.5.6.4. Assign FPGA Pin Locations

Before assigning the FPGA pins, you must know the pin layout for the board. You also must know other requirements for using the board, refer to related information below. To assign the FPGA pin locations, perform the following steps:

  1. On the Processing menu, point to Start, and click Start Analysis & Elaboration to prepare for assigning pin locations.
    The analysis starts by displaying a data not available message and can take several minutes. A confirmation message box appears when analysis and elaboration completes.
  2. Click OK.
  3. On the Assignments menu, click Pin Planner.
    The Pin Planner appears.
  4. In the Node Name column, locate PLD_CLOCKINPUT.
  5. In the PLD_CLOCKINPUT row, double-click in the Location cell to access a list of available pin locations.
  6. Select the appropriate FPGA pin that connects to the oscillator on the board.
    If your design fails to work, recheck your board documentation for this step first.
  7. In the PLD_CLOCKINPUT row, double-click in the I/O Standard cell to access a list of available I/O standards.
  8. Select the appropriate I/O standard that connects to the oscillator on the board.
  9. If you connected the LED pins in the board design schematic, repeat steps 4 to 8 for each of the LED output pins (LEDG[0], LEDG[1], LEDG[2], LEDG[3], LEDG[4], LEDG[5], LEDG[6], LEDG[7]) to assign appropriate pin locations.
  10. On the File menu, click Close to save the assignments.
  11. On the Assignments menu, click Device.
    The Device dialog box appears.
  12. Click Device and Pin Options.
    The Device and Pin Options dialog box appears.
  13. Click the Unused Pins page.
  14. In the Reserve all unused pins list, select As input tri-stated with weak pull-up. With this setting, all unused I/O pins on the FPGA enter a high-impedance state after power-up.
    Unused pins are set as input tri-stated with weak pull-up to remove contention which might damage the board. Depending on the board, you might have to make more assignments for the project to function correctly. You can damage the board if you fail to account for the board design. Consult with the maker of the board for specific contention information.
  15. Click OK to close the Device and Pin Options dialog box.
  16. Click OK to close the Device dialog box.