Construct UART Data Frame with Parity Bit

Code

#include <stdio.h>
#include <stdint.h>

typedef struct {
    uint8_t parity_enable : 1;
    uint8_t parity_type   : 1;
    uint8_t reserved      : 6;
} UART_Control;

uint8_t create_uart_frame(uint8_t data, UART_Control *ctrl) {
    // Your logic here
    uint8_t frame = 0;
    if(ctrl->parity_enable == 0)frame = data & 0x7F;
    else{
        uint8_t cnt = 0;
        uint8_t tmp = data;
        while(tmp){
            cnt += (tmp & 1);
            tmp >>= 1;
        }

        uint8_t parity_bit;
        if (ctrl->parity_type == 0) {
            // Even parity → tổng số 1 (gồm parity) phải chẵn
            parity_bit = (cnt % 2 != 0);  // nếu lẻ thì parity = 1
        } else {
            // Odd parity → tổng số 1 (gồm parity) phải lẻ
            parity_bit = (cnt % 2 == 0);  // nếu chẵn thì parity = 1
        }

        // Ghép parity bit (bit7) + 7-bit data
        frame = (parity_bit << 7) | (data & 0x7F);
    }

    return frame;
}

int main() {
    uint8_t data;
    scanf("%hhu", &data);  // 7-bit input

    uint8_t parity_enable, parity_type;
    scanf("%hhu %hhu", &parity_enable, &parity_type);

    UART_Control ctrl;
    ctrl.parity_enable = parity_enable;
    ctrl.parity_type = parity_type;

    uint8_t frame = create_uart_frame(data, &ctrl);
    printf("frame = 0x%02X", frame);

    return 0;
}

Solving Approach