The learner will review code and answer questions about the analogRead and analogWrite functions.
Analog Output Writing
All the flashcards in this set deal with the following code:
/*Assume an 8-bit analog output. Assume a 10-bit analog input. Assume maximum analog output is 5 VDC, therefore a 5 volt output would be generated by writing 255 to the analog output. A 2.5 volt output would be generated by writing 128, and a 0 volt output would be generated by writing 0.*/
int OutputPin = 3;
int analogPin = 1;
int value = 0;
void setup()
{
pinMode(OutputPin, OUTPUT);
}
void main()
{
value = analogRead(analogPin);
value = value / 4;
analogWrite(OutputPin, value);
}
This code is displayed in the image below, which will be on each card, but you may want to make note of it before going on.
Question 1 of 10
Analog Output Writing
Correct!
All the flashcards in this set deal with the following code:
/*Assume an 8-bit analog output. Assume a 10-bit analog input. Assume maximum analog output is 5 VDC, therefore a 5 volt output would be generated by writing 255 to the analog output. A 2.5 volt output would be generated by writing 128, and a 0 volt output would be generated by writing 0.*/
int OutputPin = 3;
int analogPin = 1;
int value = 0;
void setup()
{
pinMode(OutputPin, OUTPUT);
}
void main()
{
value = analogRead(analogPin);
value = value / 4;
analogWrite(OutputPin, value);
}
This code is displayed in the image below, which will be on each card, but you may want to make note of it before going on.
Correct Answer
Got it!
Question 1 of 10
Analog Output Writing
Incorrect
All the flashcards in this set deal with the following code:
/*Assume an 8-bit analog output. Assume a 10-bit analog input. Assume maximum analog output is 5 VDC, therefore a 5 volt output would be generated by writing 255 to the analog output. A 2.5 volt output would be generated by writing 128, and a 0 volt output would be generated by writing 0.*/
int OutputPin = 3;
int analogPin = 1;
int value = 0;
void setup()
{
pinMode(OutputPin, OUTPUT);
}
void main()
{
value = analogRead(analogPin);
value = value / 4;
analogWrite(OutputPin, value);
}
This code is displayed in the image below, which will be on each card, but you may want to make note of it before going on.
Your Answer
Correct Answer
Got it!
Question 1 of 10
Analog Output Writing
Correct!
Which analog output is being used?
Correct Answer
3
The code analogWrite(OutputPin, value) is where we actually send our output to the pin OutputPin. Since OutputPin has value 3, 3 is the analog output being used.
Question 1 of 10
Analog Output Writing
Incorrect
Which analog output is being used?
Your Answer
Correct Answer
3
The code analogWrite(OutputPin, value) is where we actually send our output to the pin OutputPin. Since OutputPin has value 3, 3 is the analog output being used.
Question 1 of 10
Analog Output Writing
Question 1 of 10
Analog Output Writing
Correct!
True or False: OutputPin could have been declared as a Float type variable.
Correct Answer
False
We should never use float variables for values we are going to test for equality or as arguments in functions that take integer arguments. Both the pinMode and the analogWrite functions take integer arguments.
Question 1 of 10
Analog Output Writing
Incorrect
True or False: OutputPin could have been declared as a Float type variable.
Your Answer
Correct Answer
False
We should never use float variables for values we are going to test for equality or as arguments in functions that take integer arguments. Both the pinMode and the analogWrite functions take integer arguments.
Question 1 of 10
Analog Output Writing
True or False: Essentially, this program reads the analog input 1, scales it by a factor of 4, and then writes the scaled value to analog output 3.
Question 1 of 10
Analog Output Writing
Correct!
True or False: Essentially, this program reads the analog input 1, scales it by a factor of 4, and then writes the scaled value to analog output 3.
Correct Answer
True
That is a valid explanation of what this program does.
Question 1 of 10
Analog Output Writing
Incorrect
True or False: Essentially, this program reads the analog input 1, scales it by a factor of 4, and then writes the scaled value to analog output 3.
Your Answer
Correct Answer
True
That is a valid explanation of what this program does.
Question 1 of 10
Analog Output Writing
True or False: We could rewrite the lines value = analogRead(analogPin); and value = value / 4; by replacing them with value = analogRead(analogPin) / 4; and the program would work produce the same results.
Question 1 of 10
Analog Output Writing
Correct!
True or False: We could rewrite the lines value = analogRead(analogPin); and value = value / 4; by replacing them with value = analogRead(analogPin) / 4; and the program would work produce the same results.
Correct Answer
True
value = analogRead(analogPin) / 4; would read from the pin analogPin, divide the value by 4, and store that as value, just like the separate lines of code value = analogRead(analogPin); and value = value / 4;.
Question 1 of 10
Analog Output Writing
Incorrect
True or False: We could rewrite the lines value = analogRead(analogPin); and value = value / 4; by replacing them with value = analogRead(analogPin) / 4; and the program would work produce the same results.
Your Answer
Correct Answer
True
value = analogRead(analogPin) / 4; would read from the pin analogPin, divide the value by 4, and store that as value, just like the separate lines of code value = analogRead(analogPin); and value = value / 4;.
Question 1 of 10
Analog Output Writing
If we replaced all three lines of code in the main function with analogWrite(OutputPin, analogRead(analogPin)/4); would this program function the same?
Question 1 of 10
Analog Output Writing
Correct!
If we replaced all three lines of code in the main function with analogWrite(OutputPin, analogRead(analogPin)/4); would this program function the same?
Correct Answer
Yes
The program would function the same (with the exception that value would not store anything other than 0); analogWrite(OutputPin, analogRead(analogPin)/4); will read the value on pin analogPin, scale it by a factor of 4, and then analog write that scaled value to pin OutputPin.
Question 1 of 10
Analog Output Writing
Incorrect
If we replaced all three lines of code in the main function with analogWrite(OutputPin, analogRead(analogPin)/4); would this program function the same?
Your Answer
Correct Answer
Yes
The program would function the same (with the exception that value would not store anything other than 0); analogWrite(OutputPin, analogRead(analogPin)/4); will read the value on pin analogPin, scale it by a factor of 4, and then analog write that scaled value to pin OutputPin.
Question 1 of 10
Analog Output Writing
True or False: In the line analogWrite(OutputPin, value); the value parameter is an optional parameter.
Question 1 of 10
Analog Output Writing
Correct!
True or False: In the line analogWrite(OutputPin, value); the value parameter is an optional parameter.
Correct Answer
False
The analogWrite function requires two inputs, where to write (here OutputPin) and what to write (here value).
Question 1 of 10
Analog Output Writing
Incorrect
True or False: In the line analogWrite(OutputPin, value); the value parameter is an optional parameter.
Your Answer
Correct Answer
False
The analogWrite function requires two inputs, where to write (here OutputPin) and what to write (here value).
Question 1 of 10
Analog Output Writing
If value had not been scaled by a factor of 4 in this program, what would the analog output be if the analog input was 180 hex?
Question 1 of 10
Analog Output Writing
Correct!
If value had not been scaled by a factor of 4 in this program, what would the analog output be if the analog input was 180 hex?
Correct Answer
80 hex
Since we only have an 8-bit analog output, we can only write two hex digits of output; thus 80 hex will be output when 180 hex is input.
Question 1 of 10
Analog Output Writing
Incorrect
If value had not been scaled by a factor of 4 in this program, what would the analog output be if the analog input was 180 hex?
Your Answer
Correct Answer
80 hex
Since we only have an 8-bit analog output, we can only write two hex digits of output; thus 80 hex will be output when 180 hex is input.
Question 1 of 10
Analog Output Writing
What is the numerical content of value in the analogWrite function if 2.5 VDC is being output?
Question 1 of 10
Analog Output Writing
Correct!
What is the numerical content of value in the analogWrite function if 2.5 VDC is being output?
Correct Answer
128
Since there is an 8-bit output and the maximum output is 5 VDC, then an output of 2.5 VDC must be generated by half of the maximum output, or 128. Note that the value being referenced here has already been scaled by a factor of 4.
Question 1 of 10
Analog Output Writing
Incorrect
What is the numerical content of value in the analogWrite function if 2.5 VDC is being output?
Your Answer
Correct Answer
128
Since there is an 8-bit output and the maximum output is 5 VDC, then an output of 2.5 VDC must be generated by half of the maximum output, or 128. Note that the value being referenced here has already been scaled by a factor of 4.
Question 1 of 10
Analog Output Writing
If the analog read results in a value of 3 being read into value, what would be sent to the analog output?
Question 1 of 10
Analog Output Writing
Correct!
If the analog read results in a value of 3 being read into value, what would be sent to the analog output?
Correct Answer
0
Since value is an int type, when value = value / 4; is executed, the division 3 / 4 will result in 0, so 0 will be assigned to value.
Question 1 of 10
Analog Output Writing
Incorrect
If the analog read results in a value of 3 being read into value, what would be sent to the analog output?
Your Answer
Correct Answer
0
Since value is an int type, when value = value / 4; is executed, the division 3 / 4 will result in 0, so 0 will be assigned to value.
Question 1 of 10
Analog Output Writing
True or False: value could have effectively been divided by 4 by arithmetically shifting it right twice.
Question 1 of 10
Analog Output Writing
Correct!
True or False: value could have effectively been divided by 4 by arithmetically shifting it right twice.
Correct Answer
True
Division by 4 and an arithmetic shift right by two places has the same result.
Question 1 of 10
Analog Output Writing
Incorrect
True or False: value could have effectively been divided by 4 by arithmetically shifting it right twice.
Your Answer
Correct Answer
True
Division by 4 and an arithmetic shift right by two places has the same result.
Question 1 of 10
Score
You have answered 5 of 10 questions correctly.
50%
See other flashcards and apps related to:
Question 1 of 10
- Author
- Published
- 6/2/2015
- Last Updated
- 6/2/2015
No Comments Yet
Analog Output Writing by Fox Valley Technical College is licensed under a Creative Commons Attribution 3.0 Unported License.