/*
  DVM7135 Project

  Dual Channel Digital Volt Meter
  Interfacing two ICL7135 4 1/2DVM chips to the 89S52 Microcntroller
  Signal input +/-1.9999V 100 uV sensitivity
  Serial interface: RS232C 9600 8n1
  Power Supply: 220VAC 5VA

  Copyright(c) 2011 Wichit Sirichote, wichit.sirichote@gmail.com, September 5, 2011

  This program is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by the
  Free Software Foundation; either version 2, or (at your option) any
  later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.
   
*/



#include "AT89X52.H"
#include "stdio.h"

sbit CLK= P1^7;
sbit DIN= P1^6;
sbit LOAD= P1^5;

sbit D5 = P0^4;
sbit P2D5 = P2^4;

int digit=5;
int digit2=5;
char sbuffer[8];
char sbuffer2[8];
unsigned char buffer[16];
char command;

short ready=0;
short ready2=0;
short terminal=1;
int V1=0; 
int tV1,tV2;
unsigned int temp16;

unsigned long temp32=0;

sbit RUN = P1^1;

char code convert[10] = {0x7e,0x30,0x6d,0x79,0x33,0x5b,0x5f,0x70,0x7f,0x7b};

 /* 7-segment pattern converting array
        a
       __                    register data
    f |__| b           D7  D6  D5  D4  D3  D2  D1  D0
    e |__| c.DP        DP  a   b   c   d   e   f   g
        d
*/

char code prompt[] = "\n\r >";

short pol,ov;
short pol2,ov2;

#define POLARITY 0x20
#define OVERRANGE 0x40



// shift 32-bit data to 7219 serially

shift(long n)
{
	char j;

	CLK = LOAD = 0;
	for(j=0; j<32; j++)
	{
		DIN = n&0x80000000; // send data to 7219
		CLK =1;		// pulse CLK
		CLK =0;
		n<<=1; // shift left one bit
	}
	LOAD =1;	// pulse LOAD
	LOAD =0;
}

init7219()
{
    shift(0x0a010a01); /* intensity (middle) */
    shift(0x0b070b07); /* scan limit 8 digits */
    shift(0x09000900); /* no decode mode */
    shift(0x0f000f00); /* disable test mode */
   	shift(0x0c010c01); /* normal operation */
   
}


update7219()
{
       //init7219();    /* reinitialize everytime entering to this function */
	   temp32=0;
       temp32 |= buffer[0];
       temp32<<=16;
	   temp32|= buffer[8];
	   shift(0x01000100|temp32);

	   temp32=0;
       temp32 |= buffer[1];
	   temp32<<=16;
	   temp32|= buffer[9];
	   shift(0x02000200|temp32);
       
	   temp32=0;
	   temp32 |= buffer[2];
	   temp32<<=16;
	   temp32|= buffer[10];
       shift(0x03000300|temp32);
       
	   temp32=0;
	   temp32 |= buffer[3]|0x80; // put decimal point	
	   temp32<<=16;
	   temp32|= buffer[11]|0x80;
       shift(0x04000400|temp32);

	   temp32=0;
       temp32 |= buffer[4];
	   temp32<<=16;
	   temp32|= buffer[12];
       shift(0x05000500|temp32);

	   temp32=0;
	   temp32 |= buffer[5];
       temp32<<=16;
	   temp32|= buffer[13];
	   shift(0x06000600|temp32);
       
	   temp32=0;
	   temp32 |= buffer[6];
	   temp32<<=16;
	   temp32|= buffer[14];
       shift(0x07000700|temp32);
       
	   temp32=0;
	   temp32 |= buffer[7];
	   temp32<<=16;
	   temp32|= buffer[15];
       shift(0x08000800|temp32);
}


void ex0_isr (void) interrupt 0	using 1
{
   if(D5) digit=5;
  
   sbuffer[digit]= P0&0x0F;
   buffer[8-digit]=convert[sbuffer[digit]];
   digit--;
   if(digit==0) ready=1;
   // read polarity, over range and under range
   if(P0&POLARITY) pol=1;
   else pol=0;
   if(P0&OVERRANGE) ov=1;
   else ov=0;
}

void ex1_isr (void) interrupt 2	using 2
{
   if(P2D5) digit2=5;
  
   sbuffer2[digit2]= P2&0x0F;
   buffer[16-digit2]=convert[sbuffer2[digit2]];
   digit2--;
   if(digit2==0) ready2=1;
   // read polarity, over range and under range
   if(P2&POLARITY) pol2=1;
   else pol2=0;
   if(P2&OVERRANGE) ov2=1;
   else ov2=0;
}


void over_display()
{
  buffer[3]=0x7E;
  buffer[4]=0x0E;
  buffer[5]=0;
  buffer[6]=0;
  buffer[7]=0;
}

void over_display2()
{
  buffer[11]=0x7E;
  buffer[12]=0x0E;
  buffer[13]=0;
  buffer[14]=0;
  buffer[15]=0;
}

void print_channel1()
{
 //  float temp;
   if(ready)
   {
    // ready=0;
     V1=0;
     V1 = sbuffer[5]*10000;
	 V1 += sbuffer[4]*1000;
	 V1 += sbuffer[3]*100;
	 V1 += sbuffer[2]*10;
	 V1 += sbuffer[1];

	 //RUN=0;

	// display on LED
	
	if(pol==0) buffer[2]= 0x01; // put minus sign 
	else buffer[2]=0x00;
	buffer[3] |=0x80; // put dot to buffer[3]

	if(ov) over_display();
	update7219();

	// also send to PC via serial port 9600 8n1

	if(pol==0) V1*=-1;
	tV1= V1;
//	printf("\n%.4f,",temp); 
   }
}

void print_channel2()
{
//   float temp;
   if(ready2)
   {
    // ready2=0;
     V1=0;
     V1 = sbuffer2[5]*10000;
	 V1 += sbuffer2[4]*1000;
	 V1 += sbuffer2[3]*100;
	 V1 += sbuffer2[2]*10;
	 V1 += sbuffer2[1];

	 //RUN=0;

	// display on LED
	
	if(pol2==0) buffer[10]= 0x01; // put minus sign 
	else buffer[10]=0x00;
	buffer[11] |=0x80; // put dot to buffer[3]

	if(ov2) over_display2();
	update7219();

	// also send to PC via serial port 9600 8n1

	if(pol2==0) V1*=-1;
	tV2= V1;
	//printf("%.4f",temp); 
   }
}

void pause()		  
{
    unsigned int i;
    for(i=0; i<50000;i++)
	continue;
}

void print_7135()
{
    
	//buffer[1]=0x06;
	//buffer[2]=0x4E;
	//buffer[3]=0x0E;
	buffer[12]=convert[7];
	buffer[13]=convert[1];
	buffer[14]=convert[3];
	buffer[15]=convert[5];
	update7219();
	pause(); // wait for a while
}

void print_terminal()
{

   if(ready&&ready2)
   {
    ready=0;
	ready2=0;
	printf("\n%dE-4,%dE-4",tV2,tV1);

   }



}

char getchar(void)
{
	char c;
	while(!RI);
	RI =0;
	c = SBUF;
	putchar(c);    // echo to terminal
	return SBUF;
}

void getcommand()
{
    if (RI) command = getchar(); // 
    else command = -1;             /* no cammand has entered */
}

void escape_command()
{
   if(command== 0x27)
   {
	//terminal^=1;
   }
}


void main (void)
{
SCON  = 0x50;                   /* SCON: mode 1, 8-bit UART, enable rcvr    */
TMOD |= 0x20;                   /* TMOD: timer 1, mode 2, 8-bit reload      */
TH1   = 0xfd;                   /* TH1:  reload value for 9600 baud         */
TR1   = 1;                      /* TR1:  timer 1 run                        */
TI    = 1;                      /* TI:   set TI to send first char of UART  */

T2CON = 0x00;			 // timer 2 is used to produce 120KHz for 60Hz and 125kHz for 50Hz
T2MOD |= 0x02;
TR2 =1;
RCAP2H= 0xFF;
RCAP2L= 0xEA;		 // E9 for 120kHz, EA for 125kHz


IT0 = 1;   // Configure interrupt 0 for falling edge on /INT0 (P3.2)
IT1 =1; // falling edge of INT1
EX0 = 1;   // Enable EX0 Interrupt
EX1 = 1;   // enable EX1 interrupt
EA = 1;    // Enable Global Interrupt Flag
RUN=1;   // hold

init7219();   

printf("\nDual Channel Digital VoltMeter");
print_7135();

buffer[0] = convert[2];
buffer[8]= convert[1];


while(1)
  {
 
 getcommand();
 escape_command();
 print_channel1();
 print_channel2();
 print_terminal();

  }
}