Duty cycle control for motor/LED in Embedded C - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set the PWM duty cycle to 50%.

Embedded C

PWM_SetDutyCycle([1]);

Drag options to blanks, or click blank then click option'

A0

B255

C128

D64

Attempts:

3 left

💡 Hint

Common Mistakes

Using 255 sets the duty cycle to 100%, not 50%.

Using 0 turns the output off.

The PWM duty cycle value ranges from 0 to 255. 128 sets it to about 50%.

2fill in blank

medium

Complete the code to increase the duty cycle by 10%.

Embedded C

dutyCycle = dutyCycle + [1];

Drag options to blanks, or click blank then click option'

A26

B25

C10

D15

Attempts:

3 left

💡 Hint

Common Mistakes

Using 10 increases duty cycle by too little.

Using 25 is close but less accurate.

10% of 255 is about 25.5, rounded to 26 to increase duty cycle by 10%.

3fill in blank

hard

Fix the error in the code to prevent duty cycle overflow.

Embedded C

if (dutyCycle [1] 255) {
    dutyCycle = 255;
}

Drag options to blanks, or click blank then click option'

A>=

B<

C==

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>=' causes off-by-one error.

Using '<' or '==' does not prevent overflow.

The condition should check if dutyCycle is greater than 255 to cap it at max.

4fill in blank

hard

Fill both blanks to create a dictionary that maps LED names to their duty cycles if duty cycle is above 100.

Embedded C

ledDutyCycles = { [1]: [2] for [1] in leds if [2] > 100 }

Drag options to blanks, or click blank then click option'

Aled

BdutyCycle

Cleds[led]

DledDutyCycles

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'dutyCycle' as key or value is incorrect.

Using 'ledDutyCycles' inside comprehension causes error.

The dictionary comprehension uses 'led' as key and 'leds[led]' as value, filtering values above 100.

5fill in blank

hard

Fill all three blanks to create a dictionary of LEDs with duty cycles above 150, converting LED names to uppercase.

Embedded C

highDuty = { [1]: [2] for [3] in leds if [2] > 150 }

Drag options to blanks, or click blank then click option'

Aled.upper()

Bleds[led]

Cled

DdutyCycle

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'dutyCycle' as loop variable is wrong.

Not converting LED names to uppercase.

The dictionary keys are LED names in uppercase, values are duty cycles, iterating over 'led'.