GPIOs and DACs$4$ x $5=20$ Points $$

Let the following be the configuration of the GPIOA$\_$MODER Register

x $$ unknown configuration

$31$

$30$

$29$

$28$

$27$

$26$

$25$

$24$

$23$

$22$

$21$

$20$

$19$

$18$

$17$

$16$

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

$15$

$14$

$13$

$12$

$11$

$10$

$9$

$8$

$7$

$6$

$5$

$4$

$3$

$2$

$1$

$0$

x

x

$1$

$1$

x

x

x

x

$0$

$0$

x

x

$0$

$0$

x

x

$$

a$)$ Which of the GPIO Pins on Port A have been configured already, and in which mode?

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b$)$ Suppose you need to configure GPIO PA$\mathrm{.}5$ for analog mode. Write the assembly program that accomplishes this task.

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c$)$ Suppose that the PA$\mathrm{.}5$ will serve as the DAC output pin. What does the buffered output mode do$,$ and will it be required in our configuration where PA$\mathrm{.}5$ is connected to an LED with a small resistance?

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d$)$ Assuming a $12-$bit resolution with a reference voltage of $5$V$,$ what is the minimum voltage jump that such a DAC can configure?

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e$)$ Assume that we have right$-$aligned data with $12-$bit resolution. Show the value of the DHR when the value of the saw$-$tooth wave is $5$V

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DAC$\_$DHR

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$31$

$30$

$29$

$28$

$27$

$26$

$25$

$24$

$23$

$22$

$21$

$20$

$19$

$18$

$17$

$16$

$$

$$

$$

$$

$$

$$

$$

$$

$$

$$

$$

$$

$$

$$

$$

$$

$15$

$14$

$13$

$12$

$11$

$10$

$9$

$8$

$7$

$6$

$5$

$4$

$3$

$2$

$1$

$0$

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Q$5.$ Significant questions from the midterm