Macro-Based Register Config Helper

Question

Problem: Macro-Based Register Config Helper. Solve this hands-on electronics task on EWskills.

Accepted Answer

#include 
#include 

// Field-setting macros
#define SET_ENABLE(x)  ((x & 0x01) << 0)   // Bit 0
#define SET_MODE(x)    ((x & 0x03) << 1)   // Bits 1–2
#define SET_SPEED(x)   ((x & 0x07) << 3)   // Bits 3–5
// Reserved bits 6–7 left 0

// Build register using macros
uint16_t build_register(uint8_t enable, uint8_t mode, uint8_t speed) {
    uint16_t reg = 0;

    reg |= SET_ENABLE(enable);
    reg |= SET_MODE(mode);
    reg |= SET_SPEED(speed);

    return reg;
}

int main() {
    uint8_t enable, mode, speed;
    scanf("%hhu %hhu %hhu", &enable, &mode, &speed);

    uint16_t reg = build_register(enable, mode, speed);
    printf("%u", reg);
    return 0;
}

Why Use Macros for Register Fields?

Improves readability and reuse
Avoids hardcoding bit positions
Simulates how hardware drivers are built

Macro Logic Summary

Each macro masks value to field width
Shifts it to correct bit position
OR’d into the register

13. Macro-Based Register Config Helper