Software > Software

PIC PORT value with Switch statements

<< < (2/4) > >>

Hal9000:
Oh I see now, yeah, i'll give this a try

Thanks :)

Hal9000:
ahh, ok lol. yeah, thats a pretty easy mistake to make with arrays!

Hal9000:
Actually, i'm a bit confused about the whole CCP thing......and interrupts in general. Is it true there is a naming convention for these CCPs?

what I have here (from some example code) is

Uint16 at 0x2007 __CONFIG = CONFIG_WORD;

static void Intr(void) interrupt 0
{
}

Hal9000:
/**
 * Simple Interrupt-On-B4...B7-Changed example.
 * Derived from http://tams-www.informatik.uni-hamburg.de/applets/hades/webdemos/72-pic/08-counter/count.html
 *
 * The manual says this interrupt occurs when any pin from B4 through B7
 * "changes", but this isn't exactly true.  The interrupt occurs when
 * the value WRITTEN TO B4...B7 doesn't match the value READ FROM B4...B7.
 *
 * So we set PORTB as all inputs, enable the pullup resistors to pull
 * them all high, and write 0xff to PORTB so the output matches the input.
 * Then we wait for the interrupt signalling something's pulled one down.
 *
 * When the interrupt occurs, we read the value from PORTB and write it
 * back so that the outputs match the inputs again.  If we didn't do
 * this, the interrupt would fire CONSTANTLY  instead of just ONCE since
 * the pin has ALWAYS CHANGED.
 */
#define __16f628a
#include "pic/pic16f628a.h"
#include "tsmtypes.h"
 
// Set the __CONFIG word:
// I usually set it to _EXTCLK_OSC&_WDT_OFF&_LVP_OFF&_DATA_CP_OFF&_PWRTE_ON
Uint16 at 0x2007  __CONFIG = CONFIG_WORD;

static Uint8 count;
static Uint8 breg;

// No C equivalent, so we make one with inline ASM.
// Pin interrupts can wake a PIC up, timer interrupts will not
#define sleep() __asm sleep __endasm

static void Intr(void) interrupt 0
{
   PORTA=count;   // PORTA0...A3 is count value.
   count++;   // Increment count

   breg=PORTB;   // Read PORTB inputs into breg.
   PORTB=breg;   /** Write that value back into PORTB latch values.
          * The interrupt compares the inputs to the PORTB
          * latch values, so if we don't update the latch
          * values, the interrupt will fire constantly!
          */

   RBIF=0;      // Clear PORTB4...7 interrupt flag

//   GIE=1;      // Globally enable interrupts.
         /**  We don't need to do this ourselves since
          *  the compiler ALWAYS ADDS THIS FOR US
          *  in interrupt functions!
          *  If you try and DISable interrupts in an
          *  interrupt function it WON'T WORK since
          *  the compiler ALWAYS turns them back ON!
          */
}

static void main(void)
{
   NOT_RBPU=0;      // Enable PORTB pullups

#ifdef __16f628a   // Only compile this section for PIC16f628a
        CMCON = 0x07;   /** Disable comparators.  NEEDED FOR NORMAL PORTA
                         *  BEHAVIOR ON PIC16f628a!
                         */
#endif

   TRISB=0xff;      // PORTB is all inputs
   TRISA=0x00;      // PORTA is all outputs
   PORTB=0xff;      /** The interrupt compares current
             *  inputs to PORTB latch values.
             *  We set latch values to all 1 to start.
             */
   count=0;
   PORTA=count;      // Turn PORTA outputs low

   INTCON=0x00;      // Clear interrupt register completely.
   RBIE=1;         // Enable ONLY PORTB/B4...B7 interrupt.
   GIE=1;         // Globally enable interrupts.

   while(1) sleep();   /** Wait for interrupts.  We COULD
             *  just make an infinite loop here,
             *  but sleeping saves power.
             */
}

Admin:
hmmmm i believe you already know more than i do on interrupts . . .

ive done interrupt code on the interrupt pins and timers . . . but that was years ago . . . and im a mechanical engineer . . . (Jesse, this is your cue :P)

i looked through some of my old code, but couldnt really find anything useful to help you

also, for posting code, just do 'bracket code bracket' (your code here) 'bracket /code bracket'

mozilla puts your code into a special box and looks nice, and IE . . . well it makes it look better but not by much . . .

Navigation

[0] Message Index

[#] Next page

[*] Previous page