Now that we know the LED board configuration as one of the board output mechanisms, we should be 1
able to describe a simple logic circuit in HLS for driving these LEDs. In the following slides, 2
I’m going to talk about the concept of the structure of this driver. 3
This picture shows the Basys3 board, which contains an FPGA and 16 LEDs and the connections between 4
LEDs and some of the FPGA pins. Our goal is to design a simple logic circuit to derive the corresponding pins 5
with the proper data to turn ON/OFF LEDs. 6
To control the illumination of an LED, the design, inside the FPGA, should send the logic value 7
“1” or “0” to the corresponding pin. 8
The design that generates these “1”s and “0”s would be a C function. This design is inside the FPGA and 9
is not connected to the FPGA pins. 10
Therefore, we need another part that represents the connections between the design outputs and the FPGA 11
pins. 12
These connections cannot be defined inside the C function and should be denoted in a separate file 13
by using some instructions that are known as physical constraints. 14
I will explain the constrains later in this section. Now, after being familiar with the board and having 15
a big picture of our design, 16
The question is how we can start implementing the functional blocks and their corresponding connections. 17
For this purpose, we should know more details about the design flow and the tools suitable for implementing 18
each part of a design. 19
The takeaway from this video is that an FPGA design controlling a peripheral has two main parts: A functional 20
block inside the FPGA that can be described by HLS techniques. And the connections between the functional 21
block ports and FPGA pins. Notice that both these parts are located inside the FPGA. 22
Now the quiz question. Which part can be implemented with an HLS C/C++ function? 1. The logic circuit 23
functionality inside the FPGA2. Connections between the logic circuit inside the FPGA and the FPGA pins 3. Connections 24
between the FPGA pins and the LEDs on the board