LCOM1920-T5G03

#define UART_OVERRUN_ERROR_POS                  1

#define UART_PARITY_ERROR_POS                   2

#define UART_FRAMING_ERROR_POS                  3

#define UART_OVERRUN_ERROR                      (BIT(1))

#define UART_PARITY_ERROR                       (BIT(2))

#define UART_FRAMING_ERROR                      (BIT(3))

#define UART_GET_OVERRUN_ERROR                  (((n)&UART_OVERRUN_ERROR            )>>UART_OVERRUN_ERROR_POS            )

#define UART_GET_PARITY_ERROR                   (((n)&UART_PARITY_ERROR             )>>UART_PARITY_ERROR_POS             )

#define UART_GET_FRAMING_ERROR                  (((n)&UART_FRAMING_ERROR            )>>UART_FRAMING_ERROR_POS            )

static int uart_has_communication_error(int base_addr){

    uint8_t lsr;

    if((ret = uart_get_lsr(base_addr, &lsr))) return 1;

    lsr &= (UART_OVERRUN_ERROR &

            UART_PARITY_ERROR  &

            UART_FRAMING_ERROR);

    return (lsr ? 1 : 0);

}

#include "nctp.h"

#define NCTP_START      0x80

#define NCTP_END        0xFF

#define NCTP_TRIES      3

#define NCTP_OK         0xFF

#define NCTP_NOK        0x00

#define NCTP_MAX_SIZE   1024 //in bytes

int nctp_send_char_poll(int base_addr, uint8_t  c){

    for(int i = 0; i < NCTP_TRIES; ++i)

        if(uart_transmitter_empty(base_addr))

            return uart_send_char(base_addr, c);

    return TIMEOUT_ERROR;

}

int nctp_get_char_poll (int base_addr, uint8_t *p){

    for(int i = 0; i < NCTP_TRIES; ++i)

        if(uart_receiver_ready(base_addr))

            return uart_get_char(base_addr, p);

    return TIMEOUT_ERROR;

}

int nctp_expect_ok(int base_addr){

    int ret;

    uint8_t ok;

    if((ret = nctp_get_char_poll(base_addr, &ok))) return ret;

    int cnt = 0;

    while(ok){

        cnt += ok&1;

        ok >>= 1;

    }

    if(cnt > 4) return SUCCESS;

    else        return NOK;

}

int nctp_send_char_try(int base_addr, uint8_t  c){

    int ret;

    for(size_t k = 0; k < NCTP_TRIES; ++k){

        if((ret = nctp_send_char_poll(base_addr, c))) return ret;

        if(nctp_expect_ok(base_addr) == SUCCESS) return SUCCESS;

    }

    return TRANS_FAILED;

}

int nctp_get_char_try (int base_addr, uint8_t *p){

    int ret;

    for(size_t k = 0; k < NCTP_TRIES; ++k){

        if((ret = nctp_get_char_poll (base_addr, p))) return ret;

        if(!uart_has_communication_error(base_addr))

            return nctp_send_char_try(base_addr, NCTP_OK ); //If it does not have any errors

    }

    if((ret = nctp_send_char_poll(base_addr, NCTP_NOK))) return ret;

    return TRANS_FAILED;

}

int nctp_send(int port, size_t num, uint8_t* ptr[], size_t sz[]){

    {

        int cnt = 0;

        for(size_t i = 0; i < num; ++i){

            cnt += sz[i];

            if(cnt > NCTP_MAX_SIZE) return TRANS_REFUSED;

        }

    }

    int base_addr;{

        switch(port){

            case 1: base_addr = COM1_ADDR; break;

            case 2: base_addr = COM2_ADDR; break;

            default: return INVALID_ARG;

        }

    }

    int ret;

    if((ret = uart_disable_int_rx(base_addr))) return ret;

    if((ret = uart_disable_int_tx(base_addr))) return ret;

    if((ret = nctp_send_char_try(base_addr, NCTP_START))) return ret;

    for(size_t i = 0; i < num; ++i){

        uint8_t *p = ptr[i]; size_t s = sz[i];

        for(size_t j = 0; j < s; ++j, ++p)

            if((ret = nctp_send_char_try(base_addr, *p)))

                return ret;

    }

    if((ret = nctp_send_char_try(base_addr, NCTP_END))) return ret;

int ntcp_get(int port, uint8_t *dest){

    int base_addr;{

        switch(port){

            case 1: base_addr = COM1_ADDR; break;

            case 2: base_addr = COM2_ADDR; break;

            default: return INVALID_ARG;

        }

    }

    free(dest);

    dest = malloc(NCTP_MAX_SIZE*sizeof(uint8_t)); size_t i = 0;

    if(dest == NULL) return NULL_PTR;

    uint8_t c;

    if((ret = nctp_get_char_try (base_addr, &c     ))) return ret;

    while(true){

        if(i >= NCTP_MAX_SIZE) return TRANS_REFUSED;

        if((ret = nctp_get_char_try (base_addr, &c))) return ret;

        if(c == NCTP_END) break;

        else              dest[i] = c;

        ++i;

    }