topic Re: Rx interrupt error in 8-bit Microcontrollers

Rx interrupt error

DavidoBG — Fri, 09 Jan 2009 18:38:52 GMT

Find my following code under here

void interrupt VectorNumber_Vscirx isr_rx(void)
{
unsigned char RX_car;   // Caractere reçu

Cod_err = 0;
RX_car = SCID;  // read SCI1S1 to check for receive errors
if (RX_car & 7)     // is there any rx errors?
{ // yes, make a dummy read of the rx data and return
       // dummy read of rx data to clear the interrupt flag
    //Buf_car[No_car] = RX_car;
    //No_car++;
    Cod_err = 3;
    RX_car = SCID;
    return;
}

When my interrupt run, my check error reception (RX_car & 7) is always true.

I already check SCI1S1 register and i can see:

PF=0; FE=0; NF=0; OR=0; IDLE=1; RDRF=1; TC=1; TDRE=1

So whait is the error?

Thanks

David

Re: Rx interrupt error

DavidoBG — Fri, 09 Jan 2009 18:46:32 GMT

More explanations

Before RX_car = SCID so SCI1S1 =>PF=0; FE=0; NF=0; OR=0; IDLE=1; RDRF=1; TC=1; TDRE=1

After RX_car = SCID so SCI1S1 =>PF=0; FE=0; NF=0; OR=0; IDLE=0; RDRF=0; TC=1; TDRE=1

so if (RX_car & 7) always true!!!

Re: Rx interrupt error

erooll — Sun, 11 Jan 2009 02:17:52 GMT

RX_car = SCID; // read SCI1S1 to check for receive errors

in the above line RX_car load data register, you need read status register

RX_car = SCI1S1;