i've paid attention but i didn't get it. let me see if i understand.

i have this code:

void enviar_comando(unsigned char direccion, unsigned char comando, unsigned char parametros[3]){
    unsigned char i;
    SBUF=direccion;
    while(TI==1);
    SBUF=comando;
    while(TI==1);
    for(i=0;i<3;i++){
        trama[2+i]=parametros[i];
        while(TI==1);
    }
}

you said it must be, like:

void enviar_comando(unsigned char direccion, unsigned char comando, unsigned char parametros[3]){
    unsigned char i;
    SBUF=direccion;
    SBUF=comando;
    for(i=0;i<3;i++){
        trama[2+i]=parametros[i];
    }
}

to make it rigth? i'll do like that and try to see what happends.