Can't implement microcontroller in Proteus

[robi10101298]

Hello guys,
I'm trying to build a graphic display thermometer in Proteus, with an LM35 sensor using the ATmega 164 microcontroller.

My problem is that I don't know how to connect the temperature sensor to the microcontroller.

• What am I doing wrong?
• Are the wires connected OK? If not, why?

 

[Harald Kapp]

Are the wires connected OK? If not, why?

Assuming pin 1 of the LM35 and pin 4 of the Atmega are connected to +5 V, the wiring of the sensor is o.k.

What am I doing wrong?

To answer this we need to know:

• What is the expected behavior?
• What is the error you observe?
• Have you verified that the LCD is controlled correctly (e.g. by having it show some dummy values)?

Show us your code (use the Insert... -> Code box in the menu bar).

 

[robi10101298]

Assuming pin 1 of the LM35 and pin 4 of the Atmega are connected to +5 V, the wiring of the sensor is o.k.


To answer this we need to know:

• What is the expected behavior?
• What is the error you observe?
• Have you verified that the LCD is controlled correctly (e.g. by having it show some dummy values)?

Show us your code (use the Insert... -> Code box in the menu bar).

Here its my code that was done using the CodeVisionAVR and my final schematic. As you can see, instead of 26 degrees I have 26.9, so I think it's only a calculation thing:

#include <mega164a.h>
#include <stdio.h>
#include <delay.h>

// Alphanumeric LCD functions
#include <alcd.h>

// Declare your global variables here

// Voltage Reference: 1.1V, cap. on AREF
#define ADC_VREF_TYPE ((1<<REFS1) | (0<<REFS0) | (1<<ADLAR))
 int res = 0;
 float temperature=0.0;
// Read the 8 most significant bits
// of the AD conversion result
unsigned char read_adc(unsigned char adc_input)
{
ADMUX=adc_input | ADC_VREF_TYPE;
// Delay needed for the stabilization of the ADC input voltage
delay_us(10);
// Start the AD conversion
ADCSRA|=(1<<ADSC);
// Wait for the AD conversion to complete
while ((ADCSRA & (1<<ADIF))==0);
ADCSRA|=(1<<ADIF);
return ADCH;
}
    unsigned char buffer[16];
void main(void)
{
// Declare your local variables here

// Crystal Oscillator division factor: 1
#pragma optsize-
CLKPR=(1<<CLKPCE);
CLKPR=(0<<CLKPCE) | (0<<CLKPS3) | (0<<CLKPS2) | (0<<CLKPS1) | (0<<CLKPS0);
#ifdef _OPTIMIZE_SIZE_
#pragma optsize+
#endif

// Input/Output Ports initialization
// Port A initialization
// Function: Bit7=In Bit6=In Bit5=In Bit4=In Bit3=In Bit2=In Bit1=In Bit0=In
DDRA=(0<<DDA7) | (0<<DDA6) | (0<<DDA5) | (0<<DDA4) | (0<<DDA3) | (0<<DDA2) | (0<<DDA1) | (0<<DDA0);
// State: Bit7=T Bit6=T Bit5=T Bit4=T Bit3=T Bit2=T Bit1=T Bit0=T
PORTA=(0<<PORTA7) | (0<<PORTA6) | (0<<PORTA5) | (0<<PORTA4) | (0<<PORTA3) | (0<<PORTA2) | (0<<PORTA1) | (0<<PORTA0);

// Port B initialization
// Function: Bit7=In Bit6=In Bit5=In Bit4=In Bit3=In Bit2=In Bit1=In Bit0=In
DDRB=(0<<DDB7) | (0<<DDB6) | (0<<DDB5) | (0<<DDB4) | (0<<DDB3) | (0<<DDB2) | (0<<DDB1) | (0<<DDB0);
// State: Bit7=T Bit6=T Bit5=T Bit4=T Bit3=T Bit2=T Bit1=T Bit0=T
PORTB=(0<<PORTB7) | (0<<PORTB6) | (0<<PORTB5) | (0<<PORTB4) | (0<<PORTB3) | (0<<PORTB2) | (0<<PORTB1) | (0<<PORTB0);

// Port C initialization
// Function: Bit7=In Bit6=In Bit5=In Bit4=In Bit3=In Bit2=In Bit1=In Bit0=In
DDRC=(0<<DDC7) | (0<<DDC6) | (0<<DDC5) | (0<<DDC4) | (0<<DDC3) | (0<<DDC2) | (0<<DDC1) | (0<<DDC0);
// State: Bit7=T Bit6=T Bit5=T Bit4=T Bit3=T Bit2=T Bit1=T Bit0=T
PORTC=(0<<PORTC7) | (0<<PORTC6) | (0<<PORTC5) | (0<<PORTC4) | (0<<PORTC3) | (0<<PORTC2) | (0<<PORTC1) | (0<<PORTC0);

// Port D initialization
// Function: Bit7=In Bit6=In Bit5=In Bit4=In Bit3=In Bit2=In Bit1=In Bit0=In
DDRD=(0<<DDD7) | (0<<DDD6) | (0<<DDD5) | (0<<DDD4) | (0<<DDD3) | (0<<DDD2) | (0<<DDD1) | (0<<DDD0);
// State: Bit7=T Bit6=T Bit5=T Bit4=T Bit3=T Bit2=T Bit1=T Bit0=T
PORTD=(0<<PORTD7) | (0<<PORTD6) | (0<<PORTD5) | (0<<PORTD4) | (0<<PORTD3) | (0<<PORTD2) | (0<<PORTD1) | (0<<PORTD0);

// Timer/Counter 0 initialization
// Clock source: System Clock
// Clock value: Timer 0 Stopped
// Mode: Normal top=0xFF
// OC0A output: Disconnected
// OC0B output: Disconnected
TCCR0A=(0<<COM0A1) | (0<<COM0A0) | (0<<COM0B1) | (0<<COM0B0) | (0<<WGM01) | (0<<WGM00);
TCCR0B=(0<<WGM02) | (0<<CS02) | (0<<CS01) | (0<<CS00);
TCNT0=0x00;
OCR0A=0x00;
OCR0B=0x00;

// Timer/Counter 1 initialization
// Clock source: System Clock
// Clock value: Timer1 Stopped
// Mode: Normal top=0xFFFF
// OC1A output: Disconnected
// OC1B output: Disconnected
// 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=(0<<COM1A1) | (0<<COM1A0) | (0<<COM1B1) | (0<<COM1B0) | (0<<WGM11) | (0<<WGM10);
TCCR1B=(0<<ICNC1) | (0<<ICES1) | (0<<WGM13) | (0<<WGM12) | (0<<CS12) | (0<<CS11) | (0<<CS10);
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
// OC2A output: Disconnected
// OC2B output: Disconnected
ASSR=(0<<EXCLK) | (0<<AS2);
TCCR2A=(0<<COM2A1) | (0<<COM2A0) | (0<<COM2B1) | (0<<COM2B0) | (0<<WGM21) | (0<<WGM20);
TCCR2B=(0<<WGM22) | (0<<CS22) | (0<<CS21) | (0<<CS20);
TCNT2=0x00;
OCR2A=0x00;
OCR2B=0x00;

// Timer/Counter 0 Interrupt(s) initialization
TIMSK0=(0<<OCIE0B) | (0<<OCIE0A) | (0<<TOIE0);

// Timer/Counter 1 Interrupt(s) initialization
TIMSK1=(0<<ICIE1) | (0<<OCIE1B) | (0<<OCIE1A) | (0<<TOIE1);

// Timer/Counter 2 Interrupt(s) initialization
TIMSK2=(0<<OCIE2B) | (0<<OCIE2A) | (0<<TOIE2);

// External Interrupt(s) initialization
// INT0: Off
// INT1: Off
// INT2: Off
// Interrupt on any change on pins PCINT0-7: Off
// Interrupt on any change on pins PCINT8-15: Off
// Interrupt on any change on pins PCINT16-23: Off
// Interrupt on any change on pins PCINT24-31: Off
EICRA=(0<<ISC21) | (0<<ISC20) | (0<<ISC11) | (0<<ISC10) | (0<<ISC01) | (0<<ISC00);
EIMSK=(0<<INT2) | (0<<INT1) | (0<<INT0);
PCICR=(0<<PCIE3) | (0<<PCIE2) | (0<<PCIE1) | (0<<PCIE0);

// USART0 initialization
// USART0 disabled
UCSR0B=(0<<RXCIE0) | (0<<TXCIE0) | (0<<UDRIE0) | (0<<RXEN0) | (0<<TXEN0) | (0<<UCSZ02) | (0<<RXB80) | (0<<TXB80);

// USART1 initialization
// USART1 disabled
UCSR1B=(0<<RXCIE1) | (0<<TXCIE1) | (0<<UDRIE1) | (0<<RXEN1) | (0<<TXEN1) | (0<<UCSZ12) | (0<<RXB81) | (0<<TXB81);

// Analog Comparator initialization
// Analog Comparator: Off
// The Analog Comparator's positive input is
// connected to the AIN0 pin
// The Analog Comparator's negative input is
// connected to the AIN1 pin
ACSR=(1<<ACD) | (0<<ACBG) | (0<<ACO) | (0<<ACI) | (0<<ACIE) | (0<<ACIC) | (0<<ACIS1) | (0<<ACIS0);
// Digital input buffer on AIN0: On
// Digital input buffer on AIN1: On
DIDR1=(0<<AIN0D) | (0<<AIN1D);

// ADC initialization
// ADC Clock frequency: 625.000 kHz
// ADC Voltage Reference: 1.1V, cap. on AREF
// ADC Auto Trigger Source: Free Running
// Only the 8 most significant bits of
// the AD conversion result are used
// Digital input buffers on ADC0: On, ADC1: On, ADC2: On, ADC3: On
// ADC4: On, ADC5: On, ADC6: On, ADC7: On
DIDR0=(0<<ADC7D) | (0<<ADC6D) | (0<<ADC5D) | (0<<ADC4D) | (0<<ADC3D) | (0<<ADC2D) | (0<<ADC1D) | (0<<ADC0D);
ADMUX=ADC_VREF_TYPE;
ADCSRA=(1<<ADEN) | (0<<ADSC) | (1<<ADATE) | (0<<ADIF) | (0<<ADIE) | (1<<ADPS2) | (0<<ADPS1) | (1<<ADPS0);
ADCSRB=(0<<ADTS2) | (0<<ADTS1) | (0<<ADTS0);

// SPI initialization
// SPI disabled
SPCR=(0<<SPIE) | (0<<SPE) | (0<<DORD) | (0<<MSTR) | (0<<CPOL) | (0<<CPHA) | (0<<SPR1) | (0<<SPR0);

// TWI initialization
// TWI disabled
TWCR=(0<<TWEA) | (0<<TWSTA) | (0<<TWSTO) | (0<<TWEN) | (0<<TWIE);

// Alphanumeric LCD initialization
// Connections are 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: 20
lcd_init(20);
 
 

while (1)
      {
      // Place your code here
      lcd_clear();
      res=read_adc(0);
      temperature=res*0.442;
      sprintf(buffer, "%f", temperature);
     
      lcd_puts(buffer);
      delay_ms(1500);

      }
}

 

[Harald Kapp]

I do not understand this part:

// ADC Voltage Reference: 1.1V, cap. on AREF

There is no external 1.1 V reference connected to AREF. Internal reference would be 2.5 V or Vcc (5 V).

Ho do you arrive at this factor 0.442?

temperature=res*0.442;

By the way, doing float arithmetic on a microcontroller without floating point unit is very slow.
Try using (long) integer arithmetic like

temperature= (res*442)/1000

Division still takes a lot of time. By modifying the equation like this: 442 / 1000 = 453 / 1024 (approx.), and noting that 1024 = 2¹⁰ and also noting that a division by 2¹⁰ is equivalent to shifting the divisor 10 places to the right you get this code:

temperature = (res*453)>>10

Note: these are mere suggestions to speed up the code which is not really necessary here but may come in handy once your code grows larger and slower.

 

[robi10101298]

I do not understand this part:

There is no external 1.1 V reference connected to AREF. Internal reference would be 2.5 V or Vcc (5 V).

Ho do you arrive at this factor 0.442?

By the way, doing float arithmetic on a microcontroller without floating-point unit is very slow.
Try using (long) integer arithmetic like

temperature= (res*442)/1000

Division still takes a lot of time. By modifying the equation like this: 442 / 1000 = 453 / 1024 (approx.), and noting that 1024 = 2¹⁰ and also noting that a division by 2¹⁰ is equivalent to shifting the divisor 10 places to the right you get this code:

temperature = (res*453)>>10

Note: these are mere suggestions to speed up the code which is not really necessary here but may come in handy once your code grows larger and slower.

I've just connected a 1.1 external reference to AREF
Your code it's correct, thanks <3

 

[robi10101298]

I do not understand this part:

There is no external 1.1 V reference connected to AREF. Internal reference would be 2.5 V or Vcc (5 V).

Ho do you arrive at this factor 0.442?

By the way, doing float arithmetic on a microcontroller without floating point unit is very slow.
Try using (long) integer arithmetic like

temperature= (res*442)/1000

Division still takes a lot of time. By modifying the equation like this: 442 / 1000 = 453 / 1024 (approx.), and noting that 1024 = 2¹⁰ and also noting that a division by 2¹⁰ is equivalent to shifting the divisor 10 places to the right you get this code:

temperature = (res*453)>>10

Note: these are mere suggestions to speed up the code which is not really necessary here but may come in handy once your code grows larger and slower.

Where this res*453 comes from?

 

[Harald Kapp]

The ADC is a 10 bit type. With Vref = 1.1 V this is equivalent to a conversion factor cf = 4095 bit / 1.1 V.
From the LM35 you get an scale factor of sf_LM35 = 10 mV / 1 °C
Combining these you get temperature = reading / (cf × sf) = reading / 37.2 = reading × 0.0269
Check: 25 °C -> 250 mV -> reading = (0.25 V / 1.1. V) × 4095 = 930 -> temperature = 930 / 37,2 = 25 °C
So where does your factor 0.442 come from?

 

[robi10101298]

The ADC is a 10 bit type. With Vref = 1.1 V this is equivalent to a conversion factor cf = 4095 bit / 1.1 V.
From the LM35 you get an scale factor of sf_LM35 = 10 mV / 1 °C
Combining these you get temperature = reading / (cf × sf) = reading / 37.2 = reading × 0.0269
Check: 25 °C -> 250 mV -> reading = (0.25 V / 1.1. V) × 4095 = 930 -> temperature = 930 / 37,2 = 25 °C
So where does your factor 0.442 come from?

It was a calculation mistake, I was going to say that your answer it's correct

 

[Harald Kapp]

Where this res*453 comes from?

You want to compute 422/1000 (to use integers only instead of 0.442)
Since division by 1000 is comparatively complex but division by 1024 is really easy, you need to ransform the above equation:
453 = 442 * 1024/1000

453/1024 = 422/1000 (apart from rounding errors)

But 422 or 453, I think, as shown above, the factor is incorrect.