reception problems on UART dspic30f

[Daniel Rodriguez]

hello I have been working with the dspic30f4011, but I have a problem receiving data from the uart, I need to receive a String but I have not been able to, as after the "OERR" buffer overflow flag is raised and I clear the flag it does not take the data, the manufacturer's datasheet says to save the data before clearing the, however, I do but it only receives me 5 characters.

// _XTAL_FREQ = INTERNAL OF 7.5MHz PLL_16 = 120MHz
// FCY= _XTAL_FREQ /4
#define FOSC 7500000 //7.5MHz Define la frecuencia de oscilacion del cristal.
#define PLL 16 //SI hay PLL, 7.5MHZ X 16=120MHz
#define FCY FOSC*PLL/4 // Frecuencia de cada instruccion (4 seciones de reloj) 30MHz
// 'C' source line config statements
#include <p30F4011.h>
//DEFINIR MACROS (del archivo p30f4011 en los archivos del compilador)
_FOSC( FRC_PLL16 & CSW_FSCM_OFF) //Frecuencia de Oscilacion
_FWDT( WDT_OFF ) //Whatchdog timer
_FBORPOR( PWRT_16 & BORV20 & MCLR_EN ) //Reinicio
_FGS( CODE_PROT_OFF ) //Seguridad


void init_UART1(void) {
    U1MODEbits.UARTEN = 1; // se activa el modulo UART
    U1MODEbits.USIDL = 0; // operacion continua en IDLMODE
    U1MODEbits.ALTIO = 1; // se escoge el uart alternativoU1ATX y U1ARX
    U1MODEbits.WAKE = 0; // despertar desactivado
    U1MODEbits.LPBACK = 0; // modo de retorno desactivado
    U1MODEbits.ABAUD = 0; // aurot baudiaje desactivado
    U1MODEbits.PDSEL = 0; // 8bits sin paridad
    U1MODEbits.STSEL = 0; // y bit de stop
    // configuracion de los baud rate
    // mirar pag 506-507
    U1BRG = 32; //57600
    //interrupciones
    IPC2bits.U1RXIP = 5; //prioridad
    IFS0bits.U1RXIF = 0; //se limpia la bandera de interrupcion
    IEC0bits.U1RXIE = 0; // sin interrupciones

    U1STAbits.UTXISEL = 1;
    U1STAbits.UTXBRK = 0;
    U1STAbits.UTXEN = 1; // se activa el pin de tramsmision de datos U1ATX
    U1STAbits.UTXBF = 0;
    U1STAbits.TRMT = 0; // el registro de transmision esta vacio
    U1STAbits.URXISEL = 0; // interrupcion cuando hay un caracter en el buffer
    U1STAbits.RIDLE = 0;
    U1STAbits.ADDEN = 0; // modo de deteccion desabilidado
    U1STAbits.PERR = 0; //sin error de paridad
    U1STAbits.PERR = 0; //Sin errores de encuadre
    U1STAbits.OERR = 0; // el buffer esta limpio de recepcion
    U1STAbits.URXDA = 0; //no hay datos para recibir
}

void Read_LoRA(void) {
    int i_aux = 0;
    // Clear the overflow bit to recieve data
    while (U1STAbits.URXDA == 1) {
        if ((U1STAbits.OERR == 1)) {
            buffer_reception[i_aux] = U1RXREG;
            buffer_reception[i_aux + 1] = U1RXREG;
            buffer_reception[i_aux + 2] = U1RXREG;
            buffer_reception[i_aux + 3] = U1RXREG;
            buffer_reception[i_aux + 4] = U1RXREG;
            i_aux += 5;
            U1STAbits.OERR = 0;
        }

        if (U1STAbits.FERR == 1) {
            U1STAbits.FERR = 0;
            continue;
        }
        if (U1STAbits.PERR == 1) {
            U1STAbits.PERR = 0;
            continue;
        }

        buffer_reception[i_aux] = U1RXREG;
        i_aux++;
    }
    LATEbits.LATE8 = 1;
    __delay_ms(20);
    LATEbits.LATE8 = 0;
    __delay_ms(20);
    UART1_Send_Command("dato:");
    UART1_Send_Command(buffer_reception);
    UART1_Write(0x0D); // CR; retorno de carro"enter"
    UART1_Write(0x0A); // NF; salto del linea
}


int main(void) {
    TRISEbits.TRISE8 = 0;
    TRISCbits.TRISC15 = 0;
    TRISDbits.TRISD1 = 1;

    init_UART1();

    while (1) {
        //if available data in buffer
        if (U1STAbits.URXDA == 1) {
            Read_LoRA();
        }
        LATCbits.LATC15 = 1;
        __delay_ms(100);
        LATCbits.LATC15 = 0;
        __delay_ms(100);

    }
    return 0;
}

 

[betwixt]

I don't use that device but normally you receive when the OERR is NOT set and you reset the USART if it IS set because it means an overflow has occurred.

Brian.

 

[KlausST]

Hi,

* I don´t see where "buffer_reception" is defined in type and size.

* in "void Read_LoRA(void)" you just read 5 bytes. So you can´t expect to be more bytes in buffer_reception

Klaus

 

[FvM]

We don't know how much characters are send in a burst, also if GPIO C15 has any effect on the sender. It's most likely that the 4 character deep UART FIFO is overrun during one of the delay cycles. Instead of trying to design a special receive routine, use the standard solution, an interrupt driven receive function.

 

[Daniel Rodriguez]

Hi,

* I don´t see where "buffer_reception" is defined in type and size.

* in "void Read_LoRA(void)" you just read 5 bytes. So you can´t expect to be more bytes in buffer_reception

Klaus

you are right, I didn't add the reception_buffer variable to the code in my question, but it has a size of 40, I correct it now,