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nathan_m
Joined: 06 Feb 2010
Posts: 2
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| Please Help - Stuck in Port B Interrupt |
 Posted: Sat Feb 06, 2010 11:45 pm |
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Hi, can someone please help me with a problem I am having.
Please find below the code I have been working on. I am capturing 2 pins changing from high to low using ports RB5 & RB4 and INT_RB.
I have put a 'printf' debug line in the Port B ISR which is showing me that I am in a contentious loop.
CCS V4.093
Target PIC Microcontroller = PIC16F648A
Standard Run Mode
Target voltage = 5V
Target oscillator speed = 20Mhz Crystal
| Code: |
#include <16F648A.h>
#fuses HS, NOWDT, NOLVP, NOBROWNOUT, NOPROTECT, NOPUT
#use delay(clock=20M)
#use rs232(baud=9600, xmit=PIN_B2, rcv=PIN_B1, stream=PC)
int wgnd_buffer[4];
long wgnd_timeout;
short wgnd_timer2_started;
int c;
#INT_RB
void RB_ISR()
{
if (!input(PIN_B5)) // Wiegand Data 1 PIN goes Low
{
wgnd_timeout = 0;
shift_left(wgnd_buffer,4,1);
printf("1");
wgnd_timeout = 0;
wgnd_timer2_started = 1;
}
if (!input(PIN_B4)) // Wiegand Data 0 PIN goes low
{
wgnd_timeout = 0;
shift_left(wgnd_buffer,4,0);
printf("0");
wgnd_timeout = 0;
wgnd_timer2_started = 1;
}
// printf(" xx ";
c = input_b();
clear_interrupt(INT_RB);
}
#INT_TIMER2 // Timer 2 ISR
void Timer2_ISR() // 1 ms Timer - Used for timeout & Wiegand send timing
{
if (wgnd_timer2_started == 1)
wgnd_timeout++; // Increment Timer for Wiegand Timeout
if (wgnd_timeout >= 1000) // 200ms Wiegand "End Transmission" Timeout
{
printf(" %X,%X,%X,%X",wgnd_buffer[3],wgnd_buffer[2],wgnd_buffer[1],wgnd_buffer[0]);
wgnd_buffer[0] = 0;
wgnd_buffer[1] = 0;
wgnd_buffer[2] = 0;
wgnd_buffer[3] = 0;
wgnd_timeout = 0;
wgnd_timer2_started = 0;
printf(" %X,%X,%X,%X,\r\n",wgnd_buffer[3],wgnd_buffer[2],wgnd_buffer[1],wgnd_buffer[0]);
}
clear_interrupt(int_timer2);
}
/*
int1 check_Parity(unsigned int8 index,unsigned int32 wgnd_buffer)
{
int1 pResult =0;
unsigned int8 i=0;
for (i=index; i<index>>16) & 0xFF;
printf(bputc,"\r\nSite Code = %U ** ID Code = %LU \r\n",siteCode,idCode);
wiegandData = 0;
}
*/
void main()
{
port_b_pullups(TRUE);
delay_us(200); // Allow time to pull-up port b to +5v
setup_timer_2(T2_DIV_BY_16,0x63,2); // Setup Timer 2 - 1ms
c = input_b();
clear_interrupt(INT_RB);
clear_interrupt(INT_TIMER2);
enable_interrupts(INT_RB);
enable_interrupts(INT_TIMER2);
enable_interrupts(GLOBAL);
while(true);
{
}
}
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Sun Feb 07, 2010 1:30 am |
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| Quote: | | enable_interrupts(INT_RB); |
Troubleshoot your code. Comment out the enable line for the Timer2
interrupts. This will remove all the #int_timer2 code from the program.
See if you still get the problem. If you still get the problem, then keep
on removing code until you don't.
| Quote: |
I am capturing 2 pins changing from high to low using ports RB5 & RB4
and INT_RB.
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What is the frequency of the signals on pins RB4 and RB5 ? |
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Guest
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| Posted: Sun Feb 07, 2010 2:27 am |
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I have commented all of the code out except the following. I have also disconnected the RB4 & RB5 lines so they should both be high because of the internal pullups.
Still I am stuck in the PortB Inturrupt loop with "test" streaming out the RS232 port.
| Code: |
#include <16F648A.h>
#fuses HS, NOWDT, NOLVP, NOBROWNOUT, NOPROTECT, NOPUT
#use delay(clock=20M)
#use rs232(baud=9600, xmit=PIN_B2, rcv=PIN_B1, stream=PC)
int wgnd_buffer[4];
long wgnd_timeout;
short wgnd_timer2_started;
int c;
#INT_RB
void RB_ISR()
{
printf("test");
c = input_b();
clear_interrupt(INT_RB);
}
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| Code: |
void main()
{
port_b_pullups(TRUE);
delay_us(200); // Allow time to pull-up port b to +5v
// setup_timer_2(T2_DIV_BY_16,0x63,2); // Setup Timer 2 - 1ms
c = input_b();
// clear_interrupt(INT_TIMER2);
enable_interrupts(INT_RB);
// enable_interrupts(INT_TIMER2);
enable_interrupts(GLOBAL);
while(true);
{
}
}
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Ttelmah
Guest
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| Posted: Sun Feb 07, 2010 3:37 am |
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Realistically, I have to say you have a hardware problem.
In your code, the 'clear_interrupts(INT_RB)' is unnecessary, but won't cause any harm.
I'd expect the code to print once on wake up, since the inputs will probably be low, when power is first applied, and will then go high, when you turn on the pull-ups. Hence the interrupt will trigger, and print. Since it is repeating, it implies one of several things:
1) There is still a signal attached to one of the RB4 to RB7 pins.
2) Your board has a noise problem, either leading to it resetting, or triggering the inputs. Remember that the pull up's are only a few uA.
3) MCLR is floating.
4) The supply itself is not stable.
Best Wishes |
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nathan_m
Joined: 06 Feb 2010
Posts: 2
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| Posted: Sun Feb 07, 2010 4:06 am |
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| Thank you for your suggestions. It will give me a place to start. I will let you know how it goes. |
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