EEPROM for storing settings in Arduino - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to include the EEPROM library.

Arduino

#include <[1]>

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

AEEPROM.h

BServo.h

CSPI.h

DWire.h

Attempts:

3 left

💡 Hint

Common Mistakes

Including the wrong library like Wire.h or SPI.h instead of EEPROM.h.

The EEPROM library is included with #include <EEPROM.h> to use EEPROM functions.

2fill in blank

medium

Complete the code to write the value 42 to EEPROM address 0.

Arduino

EEPROM.[1](0, 42);

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

Aupdate

Bread

Cwrite

Dget

Attempts:

3 left

💡 Hint

Common Mistakes

Using EEPROM.read instead of EEPROM.write to store data.

Use EEPROM.write(address, value) to store a byte value at a specific address.

3fill in blank

hard

Fix the error in reading a byte from EEPROM address 1.

Arduino

byte value = EEPROM.[1](1);

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

Awrite

Bupdate

Cput

Dread

Attempts:

3 left

💡 Hint

Common Mistakes

Using EEPROM.write or EEPROM.put instead of EEPROM.read for reading.

Use EEPROM.read(address) to read a byte from EEPROM.

4fill in blank

hard

Fill both blanks to write a value only if it differs from the current EEPROM value.

Arduino

if (EEPROM.[1](5) != newValue) {
  EEPROM.[2](5, newValue);
}

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

Aread

Bwrite

Cupdate

Dget

Attempts:

3 left

💡 Hint

Common Mistakes

Using write for both reading and writing.

Not checking if the value is different before writing.

First read the current value with read, then write the new value with write if different.

5fill in blank

hard

Fill all three blanks to store and retrieve an integer value using EEPROM.put and EEPROM.get.

Arduino

int storedValue = 0;

EEPROM.[1](10, newValue);
EEPROM.[2](10, [3]);

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

Awrite

Bget

CstoredValue

Dput

Attempts:

3 left

💡 Hint

Common Mistakes

Using write and read instead of put and get for integers.

Not passing a variable to EEPROM.get.

Use EEPROM.put(address, value) to store complex data types like int, and EEPROM.get(address, variable) to retrieve it.

Practice

1. What is the main purpose of using EEPROM in an Arduino program?

easy

A. To increase the speed of the program

B. To store data permanently even when the power is off

C. To connect to the internet

D. To control the brightness of an LED

Solution

1. Step 1: Understand EEPROM functionality

   EEPROM memory keeps data saved even if the Arduino loses power.

2. Step 2: Compare options with EEPROM purpose

   Only To store data permanently even when the power is off describes permanent data storage, which matches EEPROM use.

3. Final Answer:

   To store data permanently even when the power is off -> Option B

4. Quick Check:

   EEPROM stores permanent data = A [OK]

Hint: EEPROM saves data without power loss [OK]

Common Mistakes:

• Confusing EEPROM with RAM (temporary memory)
• Thinking EEPROM speeds up the program
• Mixing EEPROM with internet or LED control

2. Which of the following is the correct syntax to write the value 42 to EEPROM address 10?

easy

A. EEPROM.save(42, 10);

B. EEPROM.read(10, 42);

C. EEPROM.write(10, 42);

D. EEPROM.store(10, 42);

Solution

1. Step 1: Recall EEPROM write syntax

   The correct function to save data is EEPROM.write(address, value);.

2. Step 2: Match syntax with options

   Only EEPROM.write(10, 42); uses EEPROM.write with correct parameter order.

3. Final Answer:

   EEPROM.write(10, 42); -> Option C

4. Quick Check:

   Write uses EEPROM.write(address, value) = D [OK]

Hint: Use EEPROM.write(address, value) to save data [OK]

Common Mistakes:

• Using EEPROM.read() to write data
• Using non-existent functions like EEPROM.store()
• Swapping address and value parameters

3. What will be the output of this Arduino code snippet?

EEPROM.write(5, 100);
int val = EEPROM.read(5);
Serial.println(val);

medium

A. Error

B. 0

C. 5

D. 100

Solution

1. Step 1: Understand EEPROM write and read

   The code writes 100 to address 5, then reads from address 5.

2. Step 2: Predict Serial output

   Reading address 5 returns 100, so Serial.println prints 100.

3. Final Answer:

   100 -> Option D

4. Quick Check:

   Write 100, read 100 = A [OK]

Hint: Read returns last written value at address [OK]

Common Mistakes:

• Expecting read to return address instead of value
• Confusing EEPROM.read() with EEPROM.write()
• Assuming default value 0 without write

4. Identify the error in this code that tries to save a setting to EEPROM:

int setting = 25;
EEPROM.read(0, setting);

medium

A. Using EEPROM.read() instead of EEPROM.write() to save data

B. Wrong address used, should be 1 instead of 0

C. Missing semicolon after variable declaration

D. EEPROM.read() requires three parameters

Solution

1. Step 1: Check function purpose

   EEPROM.read() reads data; EEPROM.write() saves data.

2. Step 2: Identify misuse in code

   The code uses EEPROM.read() with two parameters, which is incorrect for saving.

3. Final Answer:

   Using EEPROM.read() instead of EEPROM.write() to save data -> Option A

4. Quick Check:

   Write needs EEPROM.write(), not EEPROM.read() = C [OK]

Hint: Use EEPROM.write() to save, EEPROM.read() to get data [OK]

Common Mistakes:

• Confusing read and write functions
• Passing wrong number of parameters
• Assuming EEPROM.read() can save data

5. You want to save a user volume setting (0-255) in EEPROM address 20 and read it back on startup. Which code snippet correctly does this?

hard

A. EEPROM.write(20, volume);
int vol = EEPROM.read(20);

B. EEPROM.read(20, volume);
int vol = EEPROM.write(20);

C. EEPROM.save(20, volume);
int vol = EEPROM.load(20);

D. EEPROM.write(volume, 20);
int vol = EEPROM.read(volume);

Solution

1. Step 1: Save volume to EEPROM address 20

   Use EEPROM.write(20, volume); to store the value.

2. Step 2: Read volume back from address 20

   Use EEPROM.read(20); to get the saved value.

3. Final Answer:

   EEPROM.write(20, volume); int vol = EEPROM.read(20); -> Option A

4. Quick Check:

   Write then read from same address = B [OK]

Hint: Write then read from same EEPROM address [OK]

Common Mistakes:

• Swapping address and value parameters
• Using non-existent EEPROM.save() or EEPROM.load()
• Reading before writing data