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magestik
Joined: 16 Oct 2008
Posts: 59
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| redirecting input on output with PIC16F877A |
 Posted: Fri Nov 14, 2008 2:36 am |
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Hello to everybody,
I am trying a simple programm, which doesn't work as it should work.
In the main function, I just want :
PIN_D1 = PIN_C1.
PIN_D0 = PIN_C5.
Alone without the interrupt function, it works.
When I add the interrupt function (which just blink a led), the interrupt function works and the led blinks, but the DATA and CLOCK I/O doesn't work anymore.
When I invert the two functions (led blinking in the while and DATA/CLOCK in the interrupt function), nothing works...
Any ideas ?
| Code: |
#include <16F877A.h>
#fuses HS,NOWDT,NOPROTECT,NOLVP,NOBROWNOUT,NOPUT
#use delay(clock=20000000)
#use rs232(baud=115200,xmit=PIN_C4,bits=8,invert)
#define CLOCK_IN PIN_C2
#define DATA_IN PIN_C5
#define CLOCK_OUT PIN_D1
#define DATA_OUT PIN_D0
int main()
{
output_high(PIN_D7);
output_high(PIN_D6);
output_high(PIN_D5);
output_high(PIN_D4);
ext_int_edge(H_to_L);
enable_interrupts(INT_EXT);
enable_interrupts(GLOBAL);
while(1)
{
OUTPUT_BIT(CLOCK_OUT,INPUT(CLOCK_IN));
OUTPUT_BIT(DATA_OUT,INPUT(DATA_IN));
}
return 0;
}
#int_ext
void kbInterrupt()
{
output_low(PIN_D6);
delay_ms(200);
output_high(PIN_D6);
delay_ms(200);
return;
}
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Another example, if i write this :
| Code: |
while(1)
{
OUTPUT_BIT(CLOCK_OUT,INPUT(CLOCK_IN));
OUTPUT_BIT(DATA_OUT,INPUT(DATA_IN));
output_low(PIN_D6);
delay_ms(200);
output_high(PIN_D6);
delay_ms(200);
}
return 0;
}
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The redirection doesn't work. |
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MarcosAmbrose
Joined: 25 Sep 2006
Posts: 38
Location: Adelaide, Australia
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| Posted: Fri Nov 14, 2008 11:15 pm |
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Hi magestik,
Your ISR routine is taking 400mS to complete, so any changes in the Data and clock pins that you're trying to re-direct will get overlooked until the ISR routine has finished.
It has been stressed in several threads just recently, "Don't use delays in interrupt service routines!" Try using a timer interrupt to make your LED blink |
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