How embedded C differs from desktop C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a variable that stores a 16-bit unsigned integer in embedded C.

Embedded C

uint[1]_t counter = 0;

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A16

B32

C8

D64

Attempts:

3 left

💡 Hint

Common Mistakes

Using standard int without size specification

Choosing 32 or 64 bits unnecessarily

In embedded C, uint16_t is used to declare a 16-bit unsigned integer, which is common for precise control over data size.

2fill in blank

medium

Complete the code to set a specific bit (bit 3) in a hardware register named REG.

Embedded C

REG |= (1 << [1]);

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A2

B3

C4

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Off-by-one error in bit position

Using incorrect shift amount

Bit numbering starts at 0, so bit 3 means shifting 1 by 3 positions to set that bit.

3fill in blank

hard

Fix the error in the interrupt service routine declaration for an embedded system.

Embedded C

void [1] ISR_Handler(void) {
    // interrupt code
}

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A__interrupt

Binterrupt

Cinterrupt_handler

Disr

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'interrupt' without underscores

Using generic function names without ISR keyword

In many embedded C compilers, __interrupt is a keyword to declare an ISR function properly.

4fill in blank

hard

Fill both blanks to create a volatile pointer to a hardware register at address 0x4000.

Embedded C

volatile [1] * const [2] = (volatile [1] * const)0x4000;

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Auint8_t

BREG

Cint

Dptr

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-volatile pointers

Using generic int type without size

Using non-const pointer

Hardware registers are often accessed via volatile pointers to fixed addresses. uint8_t is a common type for 8-bit registers, and REG is a typical variable name for the pointer.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension-like structure in embedded C style using macros for setting bits conditionally.

Embedded C

#define SET_BIT(REG, BIT) ((REG) |= (1 << (BIT)))

void configure() {
    for (int [1] = 0; [1] < 8; [1]++) {
        if ([2] & (1 << [1])) {
            SET_BIT([3], [1]);
        }
    }
}

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Ai

Bmask

CPORTA

Dbit

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable names

Confusing mask and register names

Incorrect loop variable

The loop variable is i. The mask variable holds bits to check. PORTA is the hardware register where bits are set.