Startup sequence and reset vector in Embedded C - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define the reset vector function name correctly.

Embedded C

void [1](void) {
    // Reset handler code
}

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AReset_Handler

Binit

Cstart

Dmain

Attempts:

3 left

💡 Hint

Common Mistakes

Using main as the reset vector function name.

Using generic names like start or init.

The reset vector function is typically named Reset_Handler in embedded C to handle system reset.

2fill in blank

medium

Complete the code to declare the vector table with the reset vector at the correct position.

Embedded C

void (* const vector_table[])(void) __attribute__((section(".isr_vector"))) = {
    (void (*)(void))[1], // Initial stack pointer
    Reset_Handler,               // Reset vector
    NMI_Handler,                 // NMI handler
};

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

A0x08000000

B0x20002000

C0x20000000

D0x20001000

Attempts:

3 left

💡 Hint

Common Mistakes

Using the reset vector address instead of the stack pointer.

Using flash memory address for the stack pointer.

The initial stack pointer is usually set to the top of RAM, commonly at 0x20000000 or similar depending on the MCU.

3fill in blank

hard

Fix the error in the reset handler function prototype to match the expected signature.

Embedded C

void [1](void) {
    // Reset handler implementation
}

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

AReset_Handler

Breset_handler

DReset_Handler(void)

Attempts:

3 left

💡 Hint

Common Mistakes

Adding parameters to the reset handler function.

Using lowercase function names that do not match the vector table.

The reset handler must have the signature void Reset_Handler(void) with no parameters.

4fill in blank

hard

Fill both blanks to correctly initialize the vector table with stack pointer and reset handler.

Embedded C

void (* const vector_table[])(void) __attribute__((section(".isr_vector"))) = {
    (void (*)(void))[1], // Initial stack pointer
    [2],                 // Reset vector
};

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A0x20001000

BReset_Handler

C0x08000000

DNMI_Handler

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the stack pointer and reset handler entries.

Using incorrect addresses or handler names.

The initial stack pointer is set to 0x20001000 and the reset vector points to Reset_Handler.

5fill in blank

hard

Fill all three blanks to complete the startup code that sets the vector table base address and calls the reset handler.

Embedded C

extern void [1](void);

int main(void) {
    SCB->VTOR = (uint32_t)[2]; // Set vector table base address
    [3]();                    // Call reset handler
    while(1) {}
}

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

AReset_Handler

Bvector_table

DSystemInit

Attempts:

3 left

💡 Hint

Common Mistakes

Calling the wrong function instead of the reset handler.

Not setting the vector table base address correctly.

The startup code sets the vector table base address to vector_table and calls Reset_Handler() to start the system.