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 = data & 0x7F;

    if(ctrl->parity_enable) {
        uint8_t count = __builtin_popcount(frame);
        uint8_t parity_bit;

        if(ctrl->parity_type == 0){
            parity_bit = (count % 2);
        } else {
            parity_bit = !(count % 2);
        }

        frame |= (parity_bit << 7);
    }
    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

• Take 7-bit data from user.
• Read parity settings:
  • parity_enable → 0 or 1
  • parity_type → 0 = even, 1 = odd
• Mask data to 7 bits → data & 0x7F.
• If parity is enabled:
  • Count number of 1-bits
  • Compute even or odd parity bit
  • Put the parity bit into bit 7
• Return combined 8-bit frame.
• Print the frame in hex.