Construct UART Data Frame with Parity Bit

Code

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

#define ODD 1
#define EVEN 0

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) {
    
    data = data & 0x7F; // Keep only the 7-bit data.

    if (!ctrl->parity_enable) {
        data &= ~(1U << 7);
    } else {
        /* Count the number of 1s in the data */
        int counter = 0;
        for (int i=0; i<7; i++) {
            if ((data >> i) & 1)
                counter++;
        }

        switch(ctrl->parity_type) {
            case ODD:
                if ((counter % 2) != 0) 
                    data &= ~(1U<<7);
                else   
                    data |= (1U<<7);
                break;
            case EVEN:
                if ((counter % 2) == 0)
                    data &= ~(1U<<7);
                else 
                    data |= (1U<<7);
                break;
        }
    }

    return data;
}

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;
}

Error on instructions in Odd parity ➝ parity bit = 0 if 1s are odd, 0 if even.