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| Author |
Message |
snowbell
Guest
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| RS232 interrupts |
 Posted: Mon Dec 14, 2009 9:27 am |
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Hi,
I've tried the example EX_SISR.c but it didn't seem to work properly for me. It doesn't print the characters which I entered through Hyperterminal. It only prints "Running..." and "Buffered Data =>". I tried printing an 'a' as shown in the code below, and it managed to print it only the first time I tried to do the interrupt. Anyone can help me with this? Thanks.
| Code: |
#if defined(__PCM__)
#include <18F2620.h>
#fuses HS,NOWDT,NOPROTECT,NOLVP
#use delay(clock=12000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7)
#elif defined(__PCH__)
#include <18F2620.h>
#fuses HS,NOWDT,NOPROTECT,NOLVP
#use delay(clock=12000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7)
#elif defined(__PCD__)
#include <18F2620.h>
#fuses HS, NOWDT, NOPROTECT
#use delay(clock=12000000)
#use rs232(baud=9600, UART1A)
#endif
#define BUFFER_SIZE 32
BYTE buffer[BUFFER_SIZE];
BYTE next_in = 0;
BYTE next_out = 0;
#int_rda
void serial_isr() {
int t;
buffer[next_in]=getc();
t=next_in;
next_in=(next_in+1) % BUFFER_SIZE;
if(next_in==next_out)
next_in=t; // Buffer full !!
}
#define bkbhit (next_in!=next_out)
BYTE bgetc() {
BYTE c;
while(!bkbhit) ;
c=buffer[next_out];
next_out=(next_out+1) % BUFFER_SIZE;
return(c);
}
void main() {
enable_interrupts(int_rda);
#if defined(__PCD__)
enable_interrupts(intr_global);
#else
enable_interrupts(global);
#endif
printf("\r\n\Running...\r\n");
// The program will delay for 10 seconds and then display
// any data that came in during the 10 second delay
do {
delay_ms(10000);
printf("\r\nBuffered data => ");
while(bkbhit)
{
putc( bgetc() );
putc('a');
}
} while (TRUE);
}
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snowbell
Guest
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| Posted: Mon Dec 14, 2009 10:12 am |
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| By the way, i'm using compiler version 4.057. Thanks. |
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snowbell
Guest
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| Posted: Tue Dec 15, 2009 12:25 am |
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I've also tried this very simple code of receiving a char and then displaying it on HyperTerminal. It still doesn't display, the char that I entered in HyperTerminal. It can print "Start:" and only show 'a' the first time, after that, it seems to hang. Can anyone help please. Thanks.
| Code: |
#include <18F2620.H>
#fuses HS, NOWDT, NOPROTECT, PUT, BROWNOUT, NOLVP
#use delay(clock=12000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
//=================================
void main()
{
char c;
printf("Start: ");
while(1)
{
c = getc();
putc(c);
putc('a');
}
}
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bkamen
Joined: 07 Jan 2004
Posts: 1611
Location: Central Illinois, USA
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| Posted: Wed Dec 16, 2009 1:17 am |
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it's always a good idea to TEST to see if there is a char in the RX buffer before doing a getc().
In CCS-C that's most easily accomplished with kbhit();
Also, what kind of data are you receiving, ASCII or binary?
-Ben
_________________
Dazed and confused? I don't think so. Just "plain lost" will do. :D |
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LegolasMicrochip
Joined: 28 Jun 2009
Posts: 1
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| Posted: Tue Dec 22, 2009 6:58 am |
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It actually does not hang, in fact its waiting for the character. Until or unless it does not receive a new character it would keep waiting on the getc().
So if you would type a character through your hyperterminal then it would display 'a' again.
Also verify that your circuit is correct. |
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asmboy
Joined: 20 Nov 2007
Posts: 2128
Location: albany ny
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| to make it clearer and faster try this hack |
| Posted: Tue Dec 22, 2009 4:43 pm |
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| Code: |
// useless -> delay_ms(10000);
printf("\r\nBuffered data =>\r ");
do {
while(bkbhit)
{ putc( bgetc() ); putc('a'); }
} while (TRUE);
}
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U only see the setup print out - once and the delay does NOTHING useful anyway IF the ISR is actually working - each line with CR U send will be on a line of its own - minus all the 'a's |
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