$6\mathrm{.}10$ Lab Exercises and Assignments

L$6\mathrm{.}1$ Simple interrupt. Connect the $\frac{?}{\text{b}\text{a}\text{r}}(IRQ)$ pin of the demo board to a debounced switch that can generate a negative$-$going pulse. Write a main program and an IRQ service routine. The main program initializes the variable irq$\_$cnt to $10,$ stays in a loop, and keeps checking the value of irq$\_$cnt$.$ The $\frac{?}{\text{b}\text{a}\text{r}}(IRQ)$ service routine simply decrements irq$\_$cnt by $1$ and returns.

The lab procedure is as follows:

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Chapter $6$ Interrupts and Resets

Step $1$

Connect the $\frac{?}{\text{b}\text{a}\text{r}}(IRQ)$ pin of the demo board to a debounced switch that can generate a clean negative$-$going pulse.

Step $2$

Enter the main program and $\frac{?}{\text{b}\text{a}\text{r}}(RQ)$ service routine, assemble them, and then download them to the single$-$board computer. Remember to enable the $\frac{?}{\text{b}\text{a}\text{r}}(IRQ)$ interrupt in your program.

Step $3$

Pulse the switch ten times.

If everything works properly, you should see the BUFFALO monitor prompt after ten pulses applied to the $\frac{?}{\text{b}\text{a}\text{r}}(IRQ)$ pin.