ECEN3350-Project 4 Interrupts Solved

In this project, you will write an Interrupt Service Routine (ISR) to accomplish similar tasks as in Project 2.

Objectives:

•   Learn the value of interrupts and how they make your life easy

•   See how interrupts can also make your life very, very difficult :)

Similar to Project 2, you will choose ONE of the two parts. The first option (Option 1) builds on the LED scrolling and push buttons. The second option (Option 2) uses the WS2812 LED strip used in Project 2.

Option 1. HELLO BUFFS
For this problem, you must use interrupts for both the timer and the push button. Read the whole description of this program before starting.

As in Project 2, you must make the HELLO BUFFS message scroll across the first four 7-segment displays. But, for this assignment, you need to use the timer with interrupts rather than a delay loop.

As an additional requirement, when the lower pushbutton (KEY1) is pressed, the message should scroll at a slower rate across the display. Each time the lower push button is pressed, scroll speed should decrease, but reach a minimum speed after 3 presses of the push button. So continued presses of KEY1 do not do anything. When the upper push button (KEY0) is pressed, the message scroll speed should speed-up. Similar to the case with KEY1, if you start at the default speed, three presses of KEY0 will speed-up the message to a maximum speed and no further.

Using the pushbuttons, you should be able to slow-down and speed-up the message scroll speed from the minimum to the maximum, and back down to the minimum. You need to decide how much faster and slower the message should scroll with each button push. At the fastest speed, you should still be able to clearly read the message, and at the slowest speed, the message should still scroll at a reasonable rate (you shouldn’t have to wait for 10 seconds to see it completely scroll). In your push button ISR, consider if it is possible to see both push buttons having been pressed at the same time, and if so, what should you do about this case?

What to submit Include all of your .s files you create for this part (e.g. interrupt_example.s, exception_handler.s, interval_timer_ISR.s, pushbutton_ISR.s). You may build off the assembly interrupt example in the Monitor program (that we reviewed in class).

Option 2. LED strip
For this option, you will add push button functionality to the LED strips you implemented in Project 2. See the Project 2 description for how to setup the LED strip hardware.

You will need to handle button presses in an interrupt handler, but it’s up to you if you want to implement the LED strip writing logic in an interrupt handler or not (hint: think carefully about if using the DE10-Lite’s Interval Timer is a wise choice for timing 0.35 microseconds).

It’s up to you what action the push buttons perform for your given pattern, but the buttons need to change the pattern in a noticeable way when pressed. For example, you could have the buttons determine the speed of your pattern, or you could have multiple patterns that can be switched when a button is pressed. Make sure to include a description (as a separate text file) of what behavior your pattern/buttons does.