Lab2-Task2

/*
  Aim - Read Anbalog Voltage being applied on pad 7 through on board voltage divider circuit
        Display incoming voltage as a bar graph using on board LEDs (PORTB,PTJ)

  Program Flow -
  1. Create temporary variable to store AD conversion
  2. Create switch state depending on incoming AD conversion
  3. Configure ATD0CTL2, ATDOCTL3, ATD0CTL4, ATD0CTL5

 1. Check if ATD0STAT0 - SCF =1, FIFOR=0
 2. Read ATD0DR0 to int variable
 3. Send int variable to switching function


 Based on opted 8 bit configuration and we have divided the incoming Analog voltage into 8 bands-
 wherin the difference between the upper and lower boundary is 0.625V (5/2^8), as integers this is
 represented as a band height of 32 (2^8/8). In practical use there would be never be an instant with
 current configuration where a voltage of 5V or higher is input hence in the function LED_switch case 8
 is merely a dummy case.

 Written by - Tanishq Jain | 31/03/2020
*/


#include <hidef.h>      /* common defines and macros */
#include "derivative.h"      /* derivative-specific definitions */

void Setup(void) ;
int LED_switch(int Value) ;


void Setup(void) {

  ATD0CTL2 = 0b11100000 ; /* Switch On, Fast clear, Disable wait mode, Disable Interrupt */
  ATD0CTL3 = 0b00001100 ; /* 1 Conversion, FIFO */
  ATD0CTL4 = 0b10100101 ; /* 8 bit, 2 AD conversion per cycle, Prescale - 12 */


  DDRB = 0xFF ;   /* Making Port B as Output */
  DDRJ = 0xFF ;   /* Making Port J as Output */
  PTJ  = 0x00 ;   /* Enable LED */
}

int LED_switch(int Value) {
  switch ( Value )
  {
    case 1:
            return 0x01 ;  /* 1 LED */

    case 2:
            return 0x03 ;  /* 2 LED */

    case 3:
            return 0x07 ;  /* 3 LED */

    case 4:
            return 0x0F ;  /* 4 LED */

    case 5:
            return 0x1F ;  /* 5 LED */

    case 6:
            return 0x3F ;  /* 6 LED */

    case 7:
            return 0x7F ;  /* 7 LED */

    case 8:
            return 0xFF ;  /* 8 LED */

    default:
            return 0x00 ;  /* 0 LED */
  }
}


void main(void) {
  int AD_read ;
  Setup() ;

  while (1) {
                                      /* Initiate a Conversion */
    ATD0CTL5 = 0b10000111 ;           /* RIGHT Justified, Unsigned, One Conversion, Single Channel, Channel 7 */

    while (!(ATD0STAT0 & 0x80)) {};   /* Waiting for Conversion to be completed */

    AD_read = ATD0DR0 ;               /* Read Conversion result */
    AD_read = AD_read/32 ;            /* Divide by 32 to get floor value to match band */

    PORTB = LED_switch(AD_read) ;     /* Switching LEDs on based on switch case */
  }
}