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gp3lib.c

Go to the documentation of this file.

#include <stdio.h>
#include "gp3lib.h"

#define DEMO 1

/* This is the part that should not change for each port */

/* Private function sets argument */
static void setarg(int arg)
{
  if (arg<=255) 
    {
      gp3write(6+(arg&1));
      gp3write(0x80+(arg&1));
    }
  else 
    {
      int code=8 + (arg&1);
      gp3write(code+((arg>>8)&1));
      gp3write(0x80+(arg>>9));
      gp3write(0x80+((arg&0xFF)>>1));
    }
}



unsigned int gp3readword(void)
{
  unsigned int rv;
  rv=gp3read()<<8;
  return rv+gp3read();
}

/* The remaining functions match the description in the GP3 manual */

void gp3setLED(int onoff)
{
 gp3write(0xC+(onoff&1));
}

unsigned int gp3a2d(int chan)
{
  gp3write(0x30+((chan&7)<<1));
  return gp3readword();
}

void gp3high(int pin)
{
  gp3write(0x11+(pin<<1));
}

void gp3low(int pin)
{
  gp3write(0x10+(pin<<1));
}

void gp3toggle(int pin)
{
  gp3write(0x20+(pin<<1));
}

int gp3input(int pin)
{
  gp3write(0x21+(pin<<1));
  return gp3read();
}

void gp3settris(int tris)
{
  gp3write(2 + (tris & 1));
  gp3write(0x80+(tris>>1));
}

unsigned int gp3gettris(void)
{
  gp3write(0x56);
  return gp3read();
}

void gp3setpins(int byte)
{
  gp3write(4+(byte&1));
  gp3write(0x80+(byte>>1));
}

unsigned int gp3getpins(void)
{
  gp3write(0x57);
  return gp3read();
}

void gp3writeee(int address,int byte)
{
  setarg(address);
  gp3write(0x50+(byte&1));
  gp3write(0x80+(byte>>1));
}

unsigned int gp3readee(int address)
{
  setarg(address);
  gp3write(0x52);
  return gp3read();
}

void gp3pwm(int chan,int dc,int dfreq)
{
  setarg(dfreq);
  gp3write((chan==-1)?0x54:(0x60+(chan<<1))+(dc&1));
  gp3write(0x80+(dc>>1));
}

unsigned int gp3count(int pin,unsigned int ms)
{
  setarg(ms);
  gp3write(0x40+(pin<<1));
  return gp3readword();
}

unsigned int gp3rctime(int pin, int state)
{
  gp3write(0xE);
  gp3write(0xA0+(state&1)+(pin<<1));
  return gp3readword();
}

unsigned int gp3pulsein(int pin, int state)
{
  gp3write(0x70+(state&1)+(pin<<1));
  return gp3readword();
}

void gp3pulseout(int pin, int duration)
{
  setarg(duration);
  gp3write(0x41+(pin<<1));
}

void gp3freq(int pin, int ms, int freq)
{
  setarg(ms);
  gp3write(0xE);
  gp3write(0x80+(freq&1)+(pin<<1));
  gp3write(0x80+(freq>>8));
  gp3write(0x80+((freq&0xFF)>>1));
}

void gp3setcounter(int prescale,int ext)
{
  int ps=0;
  switch (prescale)
    {
    case 1: ps=0; break;
    case 2: ps=2; break;
    case 4: ps=4; break;
    case 8: ps=6; break;
    }
  gp3write(0xE);
  gp3write(0x90+ps+(ext&1));
}

unsigned int gp3counter(void)
{
  gp3write(0x5a);
  return gp3readword();
}

void gp3resetall(void)
{
  gp3write(0x5c);
}

void gp3reset(void)
{
  gp3write(0);
}

void gp3repeat(int count)
{
  setarg(count-1);
  gp3write(0x5b);
}

/* increment ARG */
void gp3argincr(void)
{
  gp3write(0x59);
}

/* decrement ARG */
void gp3argdecr(void)
{
  gp3write(0x58);
}

unsigned int gp3check(void)
{
  gp3write(1);
  return gp3read();  /* should be 0x33 */
}


#if DEMO

void pause()
{
  printf("Press ENTER\n");
  getchar();
}

int main(int argc, char *argv[])
{
  if (argc<2)
    {
      fprintf(stderr,"Usage: gp3lib port\n");
      return 1;
    }
  if (gp3openport(argv[1])<0)
    {
      perror(argv[1]);  // This won't give real info in Windows
      return 1;
    }
  printf("Connect an LED to the hardware PWM out line and output #7\n");
  printf("Resetting GP3...\n");
  gp3resetall();
  printf("GP3 version code=%02X\n",gp3check());
  printf("Turning onboard LED and out 7 on...\n");
  gp3setLED(1);
  gp3high(7);
  pause();
  printf("Turning LEDs off...\n");
  gp3setLED(0);
  gp3low(7);
  printf("Reading A/D: ");
  printf("%d\n",gp3a2d(0));
  printf("Setting hardware PWM to 16...\n");
  gp3pwm(-1,16,2000);
  printf("Now 50%% PWM on pin 7 for 5 seconds...\n");
  gp3pwm(7,128,5000);
  printf("gp3ready returns %d\n",gp3ready());  // should print 0
  gp3check(); // wait for done
  printf("gp3ready returns %d\n",gp3ready());  // should print 1
  printf("Closing port...\n");
  gp3closeport();
  return 0;

}

#endif

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