AVR Freaks

thanks, i have repost it

well, this is my homework on school to analyze ADC using 4051

but i dont know how to display it, on lcd and on virtual terminal

it's work... i use your second coding that use array

but the display make me confuse.. i can't mark which is analog 1-analog8 

this is what display when i turn the potensiometer number 1 untill zero% 

this is what display when i turn the potensiometer number 2 untill zero% 

okey here it is

#include <mega16.h>

#include <delay.h>
#include <stdio.h>

// Alphanumeric LCD Module functions
#include <alcd.h>
// Alphanumeric LCD Module functions
#asm
.equ __lcd_port=0x15 ;PORTC
#endasm
//#include <lcd.h>

#define ADC_VREF_TYPE 0x20

//#define ADC_VREF_TYPE 0x00

// Read the AD conversion result
unsigned int read_adc(unsigned char adc_input)
{
ADMUX=adc_input | (ADC_VREF_TYPE & 0xff);
// Delay needed for the stabilization of the ADC input voltage
delay_us(10);
// Start the AD conversion
ADCSRA|=0x40;
// Wait for the AD conversion to complete
while ((ADCSRA & 0x10)==0);
ADCSRA|=0x10;
return ADCW;
}

// Declare your global variables here

void main(void)
{

unsigned int result[8];  // A/D counts 
unsigned char looper;     // loop counter
unsigned char temp;       // PORTB manipulations
unsigned char ts[20];       // 16-character LCD line, null terminator, plus a few more


// Input/Output Ports initialization
// Port A initialization
// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In 
// State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T 
PORTA=0x00;
DDRA=0x00;

// Port B initialization
// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=Out Func1=Out Func0=Out 
// State7=T State6=T State5=T State4=T State3=T State2=0 State1=0 State0=0 
PORTB=0x0f; //0x00;
DDRB=0x0f; //0x07;
// Analog Comparator initialization
// Analog Comparator: Off
// Analog Comparator Input Capture by Timer/Counter 1: Off
ACSR=0x80;
SFIOR=0x00;

// Port C initialization
// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In 
// State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T 
PORTC=0x00;
DDRC=0x00;

// Port D initialization
// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In 
// State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T 
PORTD=0x00;
DDRD=0x00;

// Timer/Counter 0 initialization
// Clock source: System Clock
// Clock value: Timer 0 Stopped
// Mode: Normal top=0xFF
// OC0 output: Disconnected
TCCR0=0x00;
TCNT0=0x00;
OCR0=0x00;

// Timer/Counter 1 initialization
// Clock source: System Clock
// Clock value: Timer1 Stopped
// Mode: Normal top=0xFFFF
// OC1A output: Discon.
// OC1B output: Discon.
// Noise Canceler: Off
// Input Capture on Falling Edge
// Timer1 Overflow Interrupt: Off
// Input Capture Interrupt: Off
// Compare A Match Interrupt: Off
// Compare B Match Interrupt: Off
TCCR1A=0x00;
TCCR1B=0x00;
TCNT1H=0x00;
TCNT1L=0x00;
ICR1H=0x00;
ICR1L=0x00;
OCR1AH=0x00;
OCR1AL=0x00;
OCR1BH=0x00;
OCR1BL=0x00;

// Timer/Counter 2 initialization
// Clock source: System Clock
// Clock value: Timer2 Stopped
// Mode: Normal top=0xFF
// OC2 output: Disconnected
ASSR=0x00;
TCCR2=0x00;
TCNT2=0x00;
OCR2=0x00;

// External Interrupt(s) initialization
// INT0: Off
// INT1: Off
// INT2: Off
MCUCR=0x00;
MCUCSR=0x00;

// Timer(s)/Counter(s) Interrupt(s) initialization
TIMSK=0x00;



// ADC initialization
// ADC Clock frequency: 691.200 kHz
// ADC Voltage Reference: AREF pin
// ADC Auto Trigger Source: Free Running
ADMUX=ADC_VREF_TYPE & 0xff;
ADCSRA=0x84;
SFIOR&=0x1F;

// Alphanumeric LCD initialization
// Connections specified in the
// Project|Configure|C Compiler|Libraries|Alphanumeric LCD menu:
// RS - PORTC Bit 0
// RD - PORTC Bit 1
// EN - PORTC Bit 2
// D4 - PORTC Bit 4
// D5 - PORTC Bit 5
// D6 - PORTC Bit 6
// D7 - PORTC Bit 7
// Characters/line: 8
lcd_init (16);//(8);

while (1)
      {

for (looper = 0; looper < 8; looper++)
        {
        temp = PORTB;
        temp &= ~0x07;
        temp |= looper;
        PORTB = temp; // set low 3 bits of PORTB to multiplexor selector
        
        result[looper] = read_adc(0);
        }

    sprintf (ts, "%4u%4u%4u%4u", result[0], result[1], result[2], result[3]);
    lcd_gotoxy(0,0);
    lcd_puts(ts);

    sprintf (ts, "%4u%4u%4u%4u", result[4], result[5], result[6], result[7]);
    lcd_gotoxy(0,1);
    lcd_puts(ts);
      } ;
}

i'm not found yet about recommended adc clock rate on atmega16 datasheet...but some text says if i use 200kHz adc clock frequency, it will take convertion time 65 microsecond & extended convertion will take 125 micro second... is it only affect the convertion time ???

when i turn a "pot"up, this happen :

pot 0% = 0V(voltmeter) = 0 (character on LCD)

pot 1% = 0.05V(voltmeter) = 640 (char on LCD)

pot 2% = 0.10V(voltmeter) = 1280(char on LCD)

|

|

pot 100% = 5V (voltmeter) = 65472(char on LCD)

i see it change linear.

so if i use the formula :

(1% pot) 640/65472 * 5V = 0.049V (0.05V measure by voltmeter)

and so the value :

(2% pot) 1280/65472*5V = 0.098V (0.10V measure by voltmeter)

so.. is it a matter of data type ???

because it should be show the range from 0 - 1023 bit not from 0 - 65472

but when i change the variable :

unsigned char ts[20];

with

unsigned int ts[20];

it is become error like this :

[192] function argument #1 of type 'unsigned int [20]' is incompatible with required parameter of type 'unsigned char *'

[192] sprintf (ts, "%4u%4u%4u%4u", result[0], result[1], result[2], result[3]);

please, is there something wrong with "sprintf" and "int" ?

oooh.... is it affected the convertion time ?

how to measure the efffect of using analog multiplexer,

i can measure the switch time of AMUX by measure it from output of the analog multiplexer using digital oscilloscope tool like this :

 channel A to port control A AMUX

 channel B to port control B AMUX

 channel C to port control C AMUX

 channel D to port output AMUX

but it is not show graph from output of ATmega16... how can i measure it... ?