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Interruption priority problem
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Manel28



Joined: 06 May 2010
Posts: 33

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PostPosted: Wed Mar 30, 2011 2:37 am     Reply with quote

I forgot to say I'm using mplab icd 2 to debug the code
Ttelmah



Joined: 11 Mar 2010
Posts: 19545

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PostPosted: Wed Mar 30, 2011 5:09 am     Reply with quote

I'd have expected it to start working with the larger (32character) buffer.
Problem is that when 'temp==1', you may not 'see' this for the time taken to execute three tasks - how long do these take?. You need to use the debugger and _time_ the total these take to execute, and then you send 9 bytes (why not just use 'putc("ABCDEFGHI";', or a printf?), _before_ you start looking for the next packet in your code. Also, you don't show the code setting temp _back_ to zero. This should be the first line after the 'if (temp==0)' test. Now with the 32 character buffer, you can receive 18 characters after 'temp' is set, before an effective overflow would occur.

Best Wishes
Manel28



Joined: 06 May 2010
Posts: 33

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PostPosted: Wed Mar 30, 2011 6:00 am     Reply with quote

I see the problem only when it executes putc function. I have done:
Code:

while(TRUE) {
StackTask();
UDPTxTask();
UDPRxTask();

if(temp==1)
 putc('A');
 temp=0;

}

and the problem arises. However if I do something like :
Code:

int p;
while(TRUE) {
StackTask();
UDPTxTask();
UDPRxTask();

if(temp==1)
 p=5;
 temp=0;
}

I have no problem at all. The problem comes up only if I use putc. Thats why I was wondering the thing has to do with full duplex comm settings, directive #use rs232 or my MAX488. Maybe a new PIC?
Ttelmah



Joined: 11 Mar 2010
Posts: 19545

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PostPosted: Wed Mar 30, 2011 7:15 am     Reply with quote

Use ex_stisr.c.
Serial interrupt driven _transmit_ buffer.
Then your code only needs to load the output data, and the interrupt sends it.

Whatever you do though, the sequence should be:
Code:

if (temp==1) {
   temp=0;
   //Now read your data from the buffer, and send your reply data

}

You need to acknowledge that you have seen the characters ASAP.

Best Wishes
Manel28



Joined: 06 May 2010
Posts: 33

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PostPosted: Fri Apr 08, 2011 3:44 am     Reply with quote

I solved the problem. I dont know why but it seems to work when I write the byte in TXREG rather than use putc. I used as well driven transmit buffer. I did something like:
Code:

#int_tbe
void tbe_isr() {
 if(temp==1){   
 
    TXREG=interbuff[next_out];
    next_out++;
    if(next_out==lenbuff){
        next_out=0x00;
        temporizador=0;
       disable_interrupts(INT_TBE);
        }
    }
}
temtronic



Joined: 01 Jul 2010
Posts: 9245
Location: Greensville,Ontario

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PostPosted: Fri Apr 08, 2011 5:17 am     Reply with quote

You should add the option 'errors' to your use rs232(...)...

also I don't know if 8 bits and Odd parity is 'legal' for your PIC/compiler.
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