Introduction to Basys 2
Switches
Slide switches
Push button switches
Definition of Pin Number
The pin number of each
LED outputs
File: basys2.ucf
Used during implementation stage
Slide switches
Pushbutton
switches
Software
• Adept Active HDL is used for writing
Verilog code
• ISE/Webpack from Xilinx
– Purpose: create a “bit” file from a Verilog file
or schematic based source files
– The “bit” file is used to configure the basys2
board before it can perform any useful
functions.
• Adept can be used to configure the
FPGA with any suitable bit file stored on
the computer
Start Aldec Active-HDL Student
Edition
Start a New Workspace
New Design Wizard
Synthesis/Implementation Paths
We will use verilog in this class
Choose Default HDL Language
to Verilog
Design Name
Set Paths for Integrated Tools
Design Entry
Verilog File
Keyword: module/endmodule
The keywords module and endmodule
encapsulate the text that describes the module
Comments
• A pair of slashes
– // comment
– Forms a comment from the text that
follows it on the same line
• /*
*/
– /* comment */
Direction of the Signals
The direction of the input and output signals is given by
input, outout or inout (for a bi-directional signal)
There are 6 outputs as an array
Z[5:0]!
Schematic of Gates2
Concurrent Statements
To describe the output each gate, we simply write the logic
Equation for that gate preceded by the keyword assign.
The concurrent statements are statements that can be
written in any order.
wire
You can think of a wire as a wire in a circuit where actual voltages
Could be measured.
Compile
Simulate gates2.v
Create a Top-Level Test Bench
You need to create a top-level test bench so you can
use physical switches/push buttons to stimulate the design
Top-Level Verilog Test Bench
Top-Level Synthesis Option
Input and output signals are assigned to pins on the FPGA during synthesis.
Synthesize
Error Message During
Implementation Stage
Solution: incorrect Netlist
Implementation Completed
with No Error
Adept Interface
Example 1
Example 2
Start Another Design
Use Push Buttons to control LED
Platform Flash
Adept can also program a bit file into an on-board non-volatile ROM called
“Platform Flash”.
Once programmed, the Platform Flash can automatically transfer a stored bit
file to the FPGA at a subsequent power-on or reset event if the Mode Jumper
(JP3) is set to ROM.
The FPGA will remain configured until it is reset by a power-cycle event. The
Platform Flash ROM will retain a bit file until it is reprogrammed,
regardless of power-cycle events.