The system you designed in this chapter requires application software for the execution on the board. This section describes the details about the application software.
The main() function in the application software is the entry point for the execution. This function includes initialization and the required settings for all peripherals connected in the system. It also has a selection procedure for the execution of the different use cases, such as AXI GPIO and PS GPIO using EMIO interface. You can select different use cases by following the instructions on the serial terminal.
The application software is programmed to accomplish the following steps:
Initialize the AXI GPIO module.
Set a direction control for the AXI GPIO pin as an input pin, which is connected with the SW5 push button on the board. The location is fixed by a LOC constraint in the user constraint file (XDC) during system creation.
Initialize the AXI Timer module with device ID 0.
Associate a timer callback function with AXI Timer ISR.
This function is called every time the timer interrupt happens. This callback switches on the LED DS23 on the board and sets the interrupt flag.
The
main()function uses the interrupt flag to halt execution, waits for timer interrupt to happen, and then restarts the execution.Set the reset value of the timer, which is loaded to the timer during reset and timer starts.
Set timer options such as Interrupt mode and Auto Reload mode.
Initialize the PS section GPIO.
Set the PS section GPIO, channel 0, pin number 10 to the output pin, which is mapped to the MIO pin and physically connected to the LED DS23 on the board.
Set PS Section GPIO channel number 2, pin number 0, to an input pin, which is mapped to PL side pin using the EMIO interface, and is physically connected to the SW7 push button switch.
Initialize the snoop control unit global interrupt controller. Register the timer interrupt routine to interrupt ID 91, register the exceptional handler, and enable the interrupt.
Execute a sequence in the loop to select between the AXI GPIO or PS GPIO use case using the serial terminal.
The software accepts your selection from the serial terminal and executes the procedure accordingly. After the selection of the use case through the serial terminal, you must press a push button on the board as per the instruction on the terminal. This action switches off the LED DS23, starts the timer, and tells the function to wait infinitely for the timer interrupt to happen. After the timer interrupt happens, LED DS23 switches ON and restarts execution.
See the next chapter for information about using the AXI HP (High Performance) slave port with the AXI Central DMA IP.