Nexys 4 GPIO Demo
Overview
Description
The Basic User Demo project demonstrates a simple usage of the Nexys4's GPIO and UART. The behavior is as follows:
- The 16 User LEDs are tied to the 16 User Switches. While the centerUser button is pressed, the LEDs are instead tied to GND
- The 7-Segment display counts from 0 to 9 on each of its 8 digits. This count is reset when the center button is pressed. Also, single anodes of the 7-Segment display are blanked by holding BTNU, BTNL, BTND, or BTNR. Holding the center button blanks all the 7-Segment anodes.
- An introduction message is sent across the UART when the device is finished being configured, and after the center User button is pressed.
- A message is sent over UART whenever BTNU, BTNL, BTND, or BTNR is pressed.
- The Tri-Color LEDs cycle through several colors in a ~4 second loop
- Data from the microphone is collected and transmitted over the mono audio out port.
- Note that the center user button behaves as a user reset button
All UART communication can be captured by attaching the UART port to a computer running a Terminal program with 9600 Baud Rate, 8 data bits, no parity, and 1 stop bit.
Features Used
Not Used | Used | |
---|---|---|
16 user switches | X | |
16 user LEDs | X | |
Two tri-color LEDs | X | |
5 User Push Buttons | X | |
Two 4-digit 7-segment displays | X | |
4 Pmod ports | X | |
Pmod for XADC signals | X | |
12-bit VGA output | X | |
USB-UART Bridge | X | |
Serial Flash for Application Data | X | |
USB HID Host With Mouse | X | |
USB HID Host With Keyboard | X | |
Micro SD card connector | X | |
PWM audio output | X | |
PDM microphone | X | |
3-axis accelerometer | X | |
16Mbyte CellularRAM | X | |
Temperature sensor | X | |
10/100 Ethernet PHY | X |
Prerequisites
Hardware
- Nexys4 FPGA board
- Micro-USB cable
- Headphones or speaker
Software
- Vivado Design Suite 2016.4
- Newer versions can be used, but the procedure may vary slightly
Downloads
Download and Launch the Nexys 4 GPIO Demo
1) Follow the Using Digilent Github Demo Projects Tutorial. This is an HDL design project, and as such does not support Vivado SDK, select the tutorial options appropriate for a Vivado-only design. Return to this guide when prompted to check for extra hardware requirements and setup.
2) In order to fully use the demo, you will need to connect a serial terminal to your Nexys 4. Plug your board into your computer with a Micro USB cable and make sure the board is turned on. Then open a serial terminal (such as TeraTerm) on your computer. In the terminal application, setup the serial port to connect to the appropriate port for your board, with a baud rate of 9600. Then return to the Github Projects Tutorial to finish programming and running the demo.
Using the Nexys 4 GPIO Demo
1. Using the Switches with LEDs
2. Seven Segment Display
3. Tri-color LEDs
The two tri-color LEDs are set to gradually change colors at all times. The user cannot affect them in this demonstration.