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spom
Joined: 12 Jul 2007
Posts: 32
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| Problem with interrupt |
 Posted: Wed Dec 12, 2007 5:05 am |
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Hi,
I have a little problem with interrupts.
I use a stepping motor which should rotate right and after 168 steps rotate left. This works fine.
But now the motor should pause for 7 minutes and then starts again.
My Problem is, that the timer starts counting after the motor's rotation which takes approximately 15 seconds.
How can I handl this?
Thanks!
My code below:
| Code: |
#include <16f818.h>
#use delay(clock=8000000)
#fuses NOWDT,HS,NOPUT,NOPROTECT,NOBROWNOUT,NOLVP
int8 switchstate;
int16 seconds;
int8 int_count;
#define INTS_PER_SECOND 61
#int_rtcc
void clock_isr() {
if(--int_count==0) {
++seconds;
int_count=INTS_PER_SECOND;
}
}
#BYTE port_b = 6
#define FOUR_PHASE TRUE
#ifdef FOUR_PHASE
BYTE const POSITIONS[4] = {0b0101,
0b1001,
0b1010,
0b0110};
#else
BYTE const POSITIONS[8] = {0b0101,
0b0001,
0b1001,
0b1000,
0b1010,
0b0010,
0b0110,
0b0100};
#endif
drive_stepper(BYTE speed, char dir, BYTE steps)
{
static BYTE stepper_state = 0;
BYTE i;
for(i=0; i<steps; ++i) {
delay_ms(speed);
set_tris_b(0xf0);
port_b = POSITIONS[ stepper_state ];
if(dir!='R')
stepper_state=(stepper_state+1)&(sizeof(POSITIONS)-1);
else
stepper_state=(stepper_state-1)&(sizeof(POSITIONS)-1);
}
}
main()
{
BYTE speed, steps;
char dir;
int_count=INTS_PER_SECOND;
set_timer0(0);
setup_counters( RTCC_INTERNAL, RTCC_DIV_128 | RTCC_8_BIT);
enable_interrupts(INT_RTCC);
enable_interrupts(GLOBAL);
while(TRUE)
{
if(seconds == 420)
{
if(switchstate==0)
{
switchstate=1;
speed = 40;
steps = 168;
dir='F';
drive_stepper(speed,dir,steps);
delay_ms(1000);
speed = 40;
steps = 168;
dir='R';
drive_stepper(speed,dir,steps);
}
else
{
switchstate=0;
}
seconds = 0;
}
}
}
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ckielstra
Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands
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| Posted: Wed Dec 12, 2007 7:08 am |
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| Quote: | My Problem is, that the timer starts counting after the motor's rotation which takes approximately 15 seconds.
How can I handl this? |
The answer is already present in your question. Do not reset the seconds timer after you have activated the motor but do it before, i.e. direct after the 7 minutes test.
Note that your current code waits 7 minutes. Activates the motor. Waits again 7 minutes before repeating the sequence. There is a total pause of 14 minutes between the motor activations, is that as intended? |
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rnielsen
Joined: 23 Sep 2003
Posts: 852
Location: Utah
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| Posted: Wed Dec 12, 2007 9:32 am |
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One way is to place an if() statement in your ISR that will enable/disable your counting routine. You could have this variable set by your drive_stepper() routine when it reaches it's destination. It could be cleared by the ISR when your counter reaches 0.
One thing to note here, it is not a good idea to have key words as part of your variable names. int_count is an example. Bad things can happen when the mind sees this and is coasting in neutral.
Ronald |
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