segsbcd.c

/////////////////////////////////////////////////////////////////////////////
// 9S12X Program: YourProg - MiniExplanation
// Processor:     MC9S12XDP512
// Bus Speed:     20 MHz (Requires Active PLL)
// Author:        Simon Walker
// Details:       A more detailed explanation of the program is entered here
// Date:          Date Created
// Revision History :
//  each revision will have a date + desc. of changes

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

#include "pll.h"
#include "swled.h"
//#include <stdlib.h>
//#include <stdio.h>

#define SEGWSTROBE PORTA &= (~0x01); PORTA |= 0x01;
#define SEGMCOMM PORTA |= 0x02;
#define SEGMDATA PORTA &= (~0x02);

/////////////////////////////////////////////////////////////////////////////
// Local Prototypes
/////////////////////////////////////////////////////////////////////////////
int SEGNormal(byte Addr, byte Value, int DPOn);
int SEGCustom(byte Addr, byte Value, int DPOn);
int SEGCodeB(byte Addr, byte Value);
int SEGClear(byte Addr);
int SEGClearAll(void);
int SEGHexLine2(uint Value); //Display value in hex (<=FFFF)
int SEGDecLine2(uint Value); //Display value in decimal (<=9999)

/////////////////////////////////////////////////////////////////////////////
// Global Variables
/////////////////////////////////////////////////////////////////////////////

/////////////////////////////////////////////////////////////////////////////
// Constants
/////////////////////////////////////////////////////////////////////////////

/////////////////////////////////////////////////////////////////////////////
// Main Entry
/////////////////////////////////////////////////////////////////////////////
void main(void)
{
  uint count = 0;

  // main entry point - these two lines must appear first
  _DISABLE_COP();
  EnableInterrupts;
  
  
  /////////////////////////////////////////////////////////////////////////////
  // one-time initializations
  /////////////////////////////////////////////////////////////////////////////
  PLL_To20MHz();
  (void) SWLInit();

 //Initialize Timer.  OC0
  // Turn the thing on
  TSCR1 = 0b10000000; //TSCR1_TEN is bit 7.  Turn it on. 7.3.2.6
  // Set Prescale of 128
  TSCR2 = 7; //0b00000111;  //Timer rate = BUSSPD/2^7 = 20 MHz/128 = 156.25 KHz (6.4 us tick) 
  // Use channel 0 OC
  TIOS |= 0b00000001; //1
  // Toggle the pin for channel 0 (pin 9)
  TCTL2 = 0b0000001;

  //Timer for OC0 is currently set up. Let's use it.
  // 1 - Clear any pending flags
  TFLG1 = 1; // Yes, 1 clears.  Not 0

  //Arm for an event in 100 ms
  TC0 = TCNT + 15625;// 100 ms / 6.4 us = 15625

  //Initialize the 7Segs
  PORTA |= 0x03;  // Set the output state of the Mode and Write lines to high
  DDRA |= 0x03; // Set them as GPIO outputs
  DDRB = 0xFF; //Set all of Port B as output (data/command bus)

  //Later, I'll want to clear all the segments
  (void) SEGClearAll();
  
  /////////////////////////////////////////////////////////////////////////////
  // main program loop
  /////////////////////////////////////////////////////////////////////////////
  for (;;)
  {
    (void) SEGNormal(0,0xA,0);
    (void) SEGCustom(1,0b00110001,0);
    while (!TFLG1); //Spin till you see the 1 on the flag
    TFLG1 = 1; //Clear flag
    TC0 = TC0 + 15625;
    (void) SWLToggle(SWLGreen); //Toggle the green LED so I know it's working
    (void) SEGHexLine2(count++);
  }                   
}

/////////////////////////////////////////////////////////////////////////////
// Functions
/////////////////////////////////////////////////////////////////////////////

//Put a Hex symbol on a seg for the least sig.digit, decimal point opt.
int SEGNormal(byte Addr, byte Value, int DPOn)
{
  //Trim address to 3 bits (only valid values are 0b000 to 0b111)
  Addr &= 0b00000111;
  //Trim value to 4 bits (only value values ar 0x00 to 0x0f)
  Value &= 0b00001111;

  //We'll use addr to build our command by adding additional bits
  Addr |= 0b01011000; //A, Normal, Decode, Hex, No Data Coming
  //Decimal point low (0) is on, not 1
  if (DPOn) Value &= (~0x80);
  else Value |= 0x80;

  //Send command
  PORTB = Addr;
  SEGMCOMM;
  SEGWSTROBE;

  //Send data
  PORTB = Value;
  SEGMDATA;
  SEGWSTROBE;

  return 0;
}

//Put a custom symbol on a seg for the least sig.digit, decimal point opt.
int SEGCustom(byte Addr, byte Value, int DPOn)
{
  //Trim address to 3 bits (only valid values are 0b000 to 0b111)
  Addr &= 0b00000111;

  //We'll use addr to build our command by adding additional bits
  Addr |= 0b01111000; //A, Normal, no Decode, Hex, No Data Coming
  //Decimal point low (0) is on, not 1
  if (DPOn) Value &= (~0x80);
  else Value |= 0x80;

  //Send command
  PORTB = Addr;
  SEGMCOMM;
  SEGWSTROBE;

  //Send data
  PORTB = Value;
  SEGMDATA;
  SEGWSTROBE;

  return 0;
}

int SEGCodeB(byte Addr, byte Value)
{
  //Trim address to 3 bits (only valid values are 0b000 to 0b111)
  Addr &= 0b00000111;

  //We'll use addr to build our command by adding additional bits
  Addr |= 0b01010000; //B, Normal, Decode, Hex, No Data Coming

  //Send command
  PORTB = Addr;
  SEGMCOMM;
  SEGWSTROBE;

  //Send data
  PORTB = Value;
  SEGMDATA;
  SEGWSTROBE;

  return 0;
}

int SEGClear(byte Addr) 
{                
  (void) SEGCustom(Addr,0x00,0);          //Custom char, no lights
  return 0;
}

int SEGClearAll()
{
  byte i = 0; 
  for (i = 0; i < 8; ++i) //Cycle through all 8 locations
    (void) SEGClear(i);
  return 0;
}

int SEGHexLine2(uint Value) //Display value in hex (<=FFFF)
{
  byte i = 0; //Loop counter
  for(i=0; i < 4; ++i)
      (void) SEGNormal(7-i, Value >> (4*i), 0); 
    
  return 0;
}

int SEGDecLine2(uint Value) //Display value in decimal (<=9999)
{
  byte i = 0; //Loop counter  
  if(Value > 9999) Value = 9999; // Or, we could just truncate
  for(i = 0; i < 4; ++i)
  {
    (void) SEGNormal(7-i, Value%10, 0);
    Value /= 10;
  }
  return 0;
}

/////////////////////////////////////////////////////////////////////////////
// Interrupt Service Routines
/////////////////////////////////////////////////////////////////////////////