Microchip IO Dev Lcd Cmeter.c

// 
// CMeter.c
// This program displays the voltage at the input to the ADC
// in Volts as well as displays a bar graph at the bottom of
// the LCD terminal display using user defined characters.
//
// Ted Rossin
// 6-27-2003
// 6-30-2003
//

#include <pic.h>
#include <stdio.h>
#include "lcd.h"
#include "timer.h"
#include "serial.h"

unsigned char SampleADC(void);
void SetCursor(unsigned char x,unsigned char y);
void InitTerminal(void);
void DisplayBarGraph(unsigned char Count);

char bank1 Buf[21];  // Some extra memory from bank1

int main()
{
	unsigned int i;
    int voltage,whole,frac;
	unsigned char Raw;
	
	TRISB = 0x00;	// Porb B[7:0] is output
    TRISA = 0x01;   // Port A[0] is input for A/D
	ADCON1 = 0x0e;	// (left justified) 1 A/D channel
	ADCON0 = 0x81;  // FOSC/32, channel=0, ADON=1

	PORTB = 0xaa;	/* turn on some lights */

	InitRS232();
	InitTimer();
	InitTerminal();
	
	printf("%c",TERM_CLEAR);
	for(i=0;0<1;i++){
		SetCursor(0,1);
		Raw = SampleADC();
		voltage = ((200*(unsigned int)Raw)/255)*25;
		whole = voltage/1000;
		frac = (voltage - (whole*1000) + 5)/10;
    	sprintf(Buf,"ADC=%d.%2dV Raw=0x%2x\n",whole,frac,Raw);
		if(Buf[6]==' ') Buf[6] = '0';  // Fix leading zero bug
		if(Buf[16]==' ') Buf[16] = '0';  // Fix leading zero bug
		printf(Buf);
		printf("\tLoop=%u    \n",i);
		DisplayBarGraph(voltage/84);
		Waitms(10);
    	PORTB = i&0xff;
	}
}

void DisplayBarGraph(unsigned char Count)
{
    unsigned char i,NumWhole,NumFrac;

    NumWhole = Count/3;
    NumFrac = Count - (NumWhole*3);
	for(i=0;i<NumWhole;i++){
		putchar(0x83);
    }
	if(NumFrac){
	    putchar(0x80+NumFrac);
		i++;
	}
	for(;i<20;i++) putchar(' ');
}

void SetCursor(unsigned char x,unsigned char y)
{
    printf("%c%c%c",TERM_POS,x,y);
}

void InitTerminal(void)
{
	unsigned char i;

	putchar(TERM_ESC);  putchar(ESC_WRITE_CUSTOM+0);
	for(i=0;i<8;i++) putchar(0x1f);
	putchar(TERM_ESC);  putchar(ESC_WRITE_CUSTOM+1);
	for(i=0;i<8;i++) putchar(0x10);
	putchar(TERM_ESC);  putchar(ESC_WRITE_CUSTOM+2);
	for(i=0;i<8;i++) putchar(0x14);
	putchar(TERM_ESC);  putchar(ESC_WRITE_CUSTOM+3);
	for(i=0;i<8;i++) putchar(0x15);
}

unsigned char SampleADC(void)
{
//	call	Delay12us		; Wait for sample cap to charge
#asm
	bsf	_ADCON0,2	; bsf	ADCON0,GO (Start conversion)
WaitADC:
	btfsc	_ADCON0,2	; Wait for finish
	  goto	WaitADC
#endasm
	return(ADRESH);		// Fetch high 8 bits of result
}