Updated Motor Controller Code

This code uses pulses to control a motor to very slow speeds.  This code is for a 12f683 pic microcontroller.

//Motor Controller
#if defined(__XC)
    #include <xc.h>         /* XC8 General Include File */
#elif defined(HI_TECH_C)
    #include <htc.h>        /* HiTech General Include File */
#endif

#include <stdint.h>        /* For uint8_t definition */
#include <stdlib.h>

//#fuses NOMCLR,NOPROTECT,NOWDT,INTRC
#pragma config MCLRE=OFF,CP=OFF,WDTE=OFF,FOSC=INTOSCIO
#define _XTAL_FREQ 4000000

void init()
{
    //Configure GPIO Port
    //ANSEL =  0b00000001;  //Configure GPIO pins as digital GP0 set to analog
    ANSEL =  0b01111000;  //Configure GPIO pins as digital, GP4 Analog

    TRISIO = 0b11011000;  //Set GP1,GP2,GP4,GP5 as outputs
    WPU = 0x00;           //Disable weak pullups
    //Configuer AD Convertor
    ADCON0 = 0b10001101;        //AD Set up
    ADRESH = 0x00;        //Init the AD Register
    //Configure Comparator
    CMCON0 = 0xFF;   // Comparator is turned off
    CMCON1 = 0x00;   // Comparator is turned off
    //Interrupt configuration
    INTCON = 0x00;   //Disable all interrupts

    OPTION_REGbits.nGPPU = 0;
    WPU = 1<<1;     //Enable weak pullups on GP1
    //Configuer AD Convertor
    //ADCON0 = 0x00;        //AD disabled
    //ADRESH = 0x00;        //Init the AD Register
        //Configuer AD Convertor

}

int read_v()
// Read voltage from input 0
 {
    int val;
    ADCON0bits.GO=1;
    while(ADCON0bits.nDONE);
    val = (ADRESH<<2)+(ADRESL>>6);
    return val;
 }

void vdelay(int n)
 {
  int i;

  for (i=0;i<n;i++)
   {
    __delay_us(100);
   }
 }

void pwgen(int pw)
// Send pulse width
 {
  int i, n=4; // Standard time interval of 400 microseconds

  if (pw>56) // Switch over to max speed
  {
      pw = 255;
      n=1;
  }
  if (pw<16) // May not have enough drive for the motor
   {         // at low speeds, so switch to longer pulses
      n = 10;// 100 microseconds
   }
  for (i=0;i<255;i++)
   {
    if (i<pw) // Turn motor on for a fraction of the time
     {
      GPIO = 0b00000010; // Motor is connected to output 2
      vdelay(n);
     }
    if (i>pw)
     {
      GPIO = 0b00000000;
      vdelay(n);
     }
   }
 }

void main()
{
    uint8_t db_cnt;
    int v;
    init();
    GPIO = 0b00000000;
    while(1)
    {
     v = read_v();
     pwgen(v<<2); // Voltage seems to read between 0 and 15
    }

}