I2C addressing (7-bit and 10-bit) in Embedded C - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a 7-bit I2C address.

Embedded C

uint8_t address = [1]; // 7-bit I2C address

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

A0x800

B0x1FF

C0x400

D0x3C

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing an address larger than 7 bits.

The 7-bit I2C address fits in 7 bits, so 0x3C is valid. Addresses like 0x1FF exceed 7 bits.

2fill in blank

medium

Complete the code to define a 10-bit I2C address.

Embedded C

uint16_t address = [1]; // 10-bit I2C address

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

A0x3FF

B0x7F

C0x80

D0x1000

Attempts:

3 left

💡 Hint

Common Mistakes

Using values larger than 10 bits.

The 10-bit I2C address can go up to 0x3FF (1023 decimal). 0x3FF fits in 10 bits.

3fill in blank

hard

Fix the error in the code that sets a 7-bit I2C address shifted for read/write bit.

Embedded C

uint8_t address_rw = [1] << 1; // Shift 7-bit address for R/W bit

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

A0x7F

B0x3C

C0x1E

D0x78

Attempts:

3 left

💡 Hint

Common Mistakes

Shifting an already shifted address.

The 7-bit address 0x3C must be shifted left by 1 to make room for the R/W bit. Using 0x78 is already shifted and incorrect here.

4fill in blank

hard

Fill both blanks to extract the upper 2-bit and lower 8-bit parts from a 10-bit I2C address.

Embedded C

uint8_t addr_high = (address [1] 8) & 0x03; // upper 2 bits
uint8_t addr_low = address [2] 0xFF; // lower 8 bits

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

A>>

B<<

C&

D|

Attempts:

3 left

💡 Hint

Common Mistakes

Using left shift instead of right shift for upper bits.

To get the upper bits, shift right by 8 and mask with 0x03. To get lower bits, mask with 0xFF.

5fill in blank

hard

Fill all three blanks to create the 10-bit I2C address frame with R/W bit.

Embedded C

uint16_t frame = ((uint16_t)(0xF0 | ((address [1] 7) & 0x06)) [2] 8) | (address [3] 0xFF);

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

A>>

B<<

C|

D&

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up shift directions or using wrong bitwise operators.

Mask bits with AND, shift left to position, and combine with OR to form the frame.