Reading a hardware register in Embedded C - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to read the value from the hardware register.

Embedded C

volatile uint32_t value = *[1];

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A(uint32_t *)0x40021000

B0x40021000

C&0x40021000

Duint32_t *0x40021000

Attempts:

3 left

💡 Hint

Common Mistakes

Using the address without casting to a pointer type.

Trying to take the address of a literal.

Using incorrect pointer syntax.

To read a hardware register, you need to use a pointer to the register's address. Casting the address to a pointer type allows dereferencing it to get the value.

2fill in blank

medium

Complete the code to define a pointer to the hardware register address 0x40021004.

Embedded C

volatile uint32_t *reg = [1];

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

A&0x40021004

B0x40021004

C(uint32_t *)0x40021004

D(volatile uint32_t)0x40021004

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning the address without casting.

Using the address-of operator on a literal.

Casting to the wrong type.

The pointer must be assigned the address cast to the correct pointer type to access the hardware register.

3fill in blank

hard

Fix the error in the code to correctly read the hardware register value.

Embedded C

uint32_t value = *[1]0x40021008;

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A&

B(volatile uint32_t *)

C(uint32_t *)

D*

Attempts:

3 left

💡 Hint

Common Mistakes

Dereferencing the address without casting.

Using the wrong pointer type.

Using the address-of operator incorrectly.

The address must be cast to a volatile pointer type before dereferencing to read the hardware register correctly.

4fill in blank

hard

Fill both blanks to declare and read a volatile hardware register at address 0x4002100C.

Embedded C

volatile uint32_t *[1] = [2]0x4002100C;
uint32_t value = *reg;

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Areg

B(uint32_t *)

C(volatile uint32_t *)

D&

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong pointer name.

Casting to non-volatile pointer type.

Using the address-of operator incorrectly.

Declare a pointer named 'reg' as a volatile uint32_t pointer and cast the address to volatile uint32_t * before assigning.

5fill in blank

hard

Fill all three blanks to declare a volatile pointer, assign the hardware register address 0x40021010, and read its value.

Embedded C

volatile uint32_t *[1];
[2] = [3]0x40021010;
uint32_t value = *reg;

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

Areg

C(volatile uint32_t *)

D(uint32_t *)

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names for declaration and assignment.

Casting to non-volatile pointer type.

Not casting the address before assignment.

Declare the pointer 'reg', assign it the address cast to volatile uint32_t *, then read the value by dereferencing.