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Using software serial port causes output pin to stop working

 
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Dutch2



Joined: 05 Oct 2007
Posts: 8

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Using software serial port causes output pin to stop working
PostPosted: Fri Feb 01, 2008 5:03 pm     Reply with quote
My project needs to communicate on a LIN bus. I hooked the (home grown) driver to the hardware UART pins on my 16F887 but I forgot that my driver inverts so I fixed it in software by switching to a software UART and using the INVERT function:

#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, stream=LIN, force_sw, invert)

#use fast_io(C)

set_tris_c(0b10000000);

Another pin on the same port (C1) controls a indicator light.

Code:
  //fputc(0x00,LIN); 
  while (TRUE) {
    output_toggle(Indicator);
    delay_ms(100);
  }



I wrote this simple test program after my main program failed when I started using the LIN bus.

Basically the loop flashes the indicator as long as the fputc is commented out. As soon as I uncomment it, the indicator stops flashing.

Any idea what I'm doing wrong here?

Thanks in advance,

D2.
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Fri Feb 01, 2008 5:53 pm     Reply with quote
Quote:
I wrote this simple test program.

Those are actually code fragments. Post a complete test program.
Here's an example:
http://www.ccsinfo.com/forum/viewtopic.php?t=32831&start=4
It has all statements that are needed to compile it: #include, #fuses,
#use, and a main(), and the minimum lines of code needed to test
the desired feature or problem.
Dutch2



Joined: 05 Oct 2007
Posts: 8

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PostPosted: Fri Feb 01, 2008 6:23 pm     Reply with quote
Code:
#include <16f887.h>
#fuses INTRC_IO,WDT,MCLR,NOPROTECT,BROWNOUT,BORV40,NOLVP
#device ADC=10
#use delay(internal=4M)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, stream=LIN, force_sw, invert)
#use fast_io(A)
#use fast_io(B)
#use fast_io(C)
#use fast_io(D)
#use fast_io(E)

#define Indicator pin_c1

void init_system (void) {
   set_tris_a(0b11111111);              //Port a i/o
   set_tris_b(0b11111111);              //Port b i/o
   set_tris_c(0b10000000);              //Port c i/o
   set_tris_d(0b10000000);              //Port d i/o
   set_tris_e(0b00001111);              //Port e i/o
  output_c(0b10000000);
  output_d(0b10110000);
   setup_adc(ADC_CLOCK_DIV_8);
   setup_adc_ports(0x300FF);
   setup_wdt(WDT_144MS);

}

void main(void) {
  init_system();
  //fputc(0x00,LIN);
  while (True) {
    output_toggle(Indicator);
    delay_ms(100);
    restart_wdt();
   }
}


PCM version 4.065
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Fri Feb 01, 2008 6:41 pm     Reply with quote
Try a more simple test program:
Code:
#include <16F887.h>
#fuses INTRC_IO,MCLR,NOPROTECT,BROWNOUT,BORV40,NOLVP
#use delay(internal=4M)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, stream=LIN, force_sw, invert)

#define INDICATOR PIN_C1

//============================
void main(void)
{
fputc(0x00, LIN);

while(True)
  {
   output_toggle(Indicator);
   delay_ms(100);
  }
}
Dutch2



Joined: 05 Oct 2007
Posts: 8

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PostPosted: Fri Feb 01, 2008 6:58 pm     Reply with quote
Yep, that works. Any idea what is causing this?

Thanks,

D2.
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Fri Feb 01, 2008 7:04 pm     Reply with quote
Add the lines of code back in, one or two at a time, until it fails.
See which line causes the failure.
Dutch2



Joined: 05 Oct 2007
Posts: 8

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PostPosted: Sat Feb 02, 2008 10:21 am     Reply with quote
Whenever I use fast_io for port C it stops working.

I checked another project where I used a software serial port on port B where I did not encounter this issue.
Code:
#include <16f876a.h>
#fuses HS,NOWDT,NOPROTECT,NOBROWNOUT,NOLVP
#device ADC=10
#use delay(clock=16000000)
#use rs232(baud=19200, xmit=PIN_C6, rcv=PIN_C7, stream=PC)
#use rs232(baud=19200, xmit=PIN_B4, rcv=PIN_B5, stream=LIN, invert)
#use fast_io(b)
#use fast_io(c)

Any ideas why I am seeing this issue now?

D2.
Ttelmah
Guest
PostPosted: Sat Feb 02, 2008 11:17 am     Reply with quote
Because on that project you were using the hardware serial on port C.

Best Wishes
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