[avr-gcc-list] USART Tx Interrupts problem.

[Yuri Vignoli]

I'm using an ATMEGA8L
I write a interrupt routine for managing  Data Register Empty interrupt, 
but it's not called after i wrote the first char in UDR, it sends only 
this char.

This is the send function

BOOL com_send(u8_t* pBuf, u8_t nChar)
{

 /* control if the buffer is full */
 if .....
 {
   return FALSE;
 }

 /*--- copy characters in buffer  ---*/
 for( ..... )
 {
  
   /*--- set correct index for circular buffer  ---*/
   ......
 }
 /*--- disable interrupts for managing shared data which modify on 
interrupt ---*/
 ios_di();
 /* buffer not empty */
 if ....
 {
   /* enable interrupts */
   UCSRB |=  (COM_UDRIE | COM_TXCIE);
   /* write buffer char on UDR */
   UDR = .....
   /*--- set correct index for circular buffer  and increments number 
of char to send strored in buffer ---*/
   .....
 }
 else
 {
   /* incrementes number of char to send strored in buffer*/
 }
 /* reenable interrupts */
 ios_ei();

 return TRUE;
}

The interrupt routine is so declared.


void DataRegHandler() __attribute__ ((interrupt));

void DataRegHandler()
{
  /* turn a led on */
.....
/* get the next char on shared buffer */
/* control if i have other chars to send, if no clear UDRIE  */
if ....
{
.........
}
}

The routine address is on the right position of inerrupt vector and 
interrputs on TXCIE and UDRIE are set  in send function.

Regards,

Yuri Vignoli.