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;
    } else {
        uint8_t c = 0;
        for (uint8_t i = 0; i < 8; i++) {
            if (data & (1 << i)) c++;
        }
        if ((*ctrl).parity_type == 0) {
            if ((c & 1) == 0) frame = data;
            else frame = (1 << 7) | data;
        } else {
            if ((c & 1) != 0) frame = data;
            else frame = (1 << 7) | data;
        }
    }
    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

 

 

 

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Input

85 1 0

Expected Output

frame = 0x55