ATmega32 avr

[s.manisrinivas]

after working severals hour I still have trouble doing master receiver and slave transmitter if someone has code … (ATMEGA32)  please provide some suggestions for coding.

i got this code in internet ,can anybody tell me flow of code .

I want read adc value from slave transmitter and the value should  display by master in lcd display .

slave transmitter code………….

#include <avr/io.h>

#include <avr/interrupt.h>

 

#define F_CPU 1000000UL  // 1 MHz

#include <util/delay.h>

#include <util/twi.h>

 

#define SLAVE_ADDRESS (0x01)

 

uint8_t adc_value; // the value to send

 

// interrupt routine for TWI message handling

ISR(TWI_vect)

{

// react on TWI status and handle different cases

uint8_t status = TWSR & 0xFC; // mask-out the prescaler bits

switch(status)

{

case TW_ST_SLA_ACK:   // own SLA+R received, acknoledge sent

TWDR = adc_value;

TWCR &= ~((1<<TWSTO) | (1<<TWEA));

break;

 

case TW_ST_LAST_DATA: // last byte transmitted ACK received

TWCR |= (1<<TWEA); // set TWEA to enter slave mode

break;

}

TWCR |= (1<<TWINT);  // set TWINT -> activate TWI hardware

}

 

int main(void)

{

// TWI setup

sei(); // enable global interrupt

 

// set slave address to 0x01, ignore general call

TWAR = (SLAVE_ADDRESS << 1) | 0x00;

// TWI-ENable , TWI Interrupt Enable

TWCR |= (1<<TWEA) | (1<<TWEN) | (1<<TWIE);

 

// ADC setup

ADCSRA |= (1<<ADEN);

ADMUX  |= ( (1<<REFS1) | (1<<REFS0) ); // select internal reference

ADMUX  |= 3;   // select channel 5 (pin ADC5)

 

// infinite loop

for (;

{

ADCSRA |= (1<<ADSC);        // start single measurement

while(ADCSRA & (1<<ADSC));  // wait until measurement done

 

// read result bytes (low and high) and reduce to 8-bits

adc_value = ADCL;

adc_value >>= 2;          // drop 2 least significant bits

adc_value |= (ADCH << 6); // add two most significant bits

}

}

 

 

 

 

master receiver code………….

 

 

#include <avr/io.h>

#define F_CPU 1000000UL  // 1 MHz

#include <util/delay.h>

 

#include <avr/interrupt.h>

#include <util/twi.h>

 

#define SLAVE_ADDRESS (0x01)

 

uint8_t value; // contains the received value

 

uint8_t ongoing_transmission = 0;

 

// interrupt routine for the timer0 overflow interrupt

ISR(TWI_vect)

{

// react on TWI status and handle different cases

uint8_t status = TWSR & 0xFC; // mask-out the prescaler bits

switch(status)

{

case TW_START:  // start transmitted

ongoing_transmission = 1;

// write SLA+R, SLA=0x01

TWDR = (SLAVE_ADDRESS << 1) | 0x01;

TWCR &= ~((1<<TWSTA)); // clear TWSTA

break;

 

case TW_MR_SLA_ACK: // SLA+R transmitted, ACK received

TWCR &= ~((1<<TWSTA) | (1<<TWSTO));

break;

 

case TW_MR_DATA_ACK: // data received, ACK returned

ongoing_transmission = 0;

value = TWDR;

TWCR |= (1<<TWSTO);  // write stop bit

TWCR &= ~(1<<TWSTA); // clear start bit

break;

}

TWCR |=   (1<<TWINT);  // hand over to TWI hardware

}

 

int main(void)

{

// TWI setup

sei(); // enable global interrupt

// TWI-ENable , TWI Interrupt Enable

TWCR |= (1<<TWEA) | (1<<TWEN) | (1<<TWIE);

 

// LED setup

DDRB  = 0x3f; // PORTB[0:5] as output

DDRC  = 0x03; // PORTC[0:1] as output

 

for (; // infinite main loop

{

// initiate new transmission if

//    no transmission is in progress

if (!ongoing_transmission) TWCR |= (1<<TWSTA);

 

PORTB = value;    // display number

PORTC = value>>6; //   as LED pattern

}

}

 

[Ashutosh Bhatt]

what is the problem in your code?

[s.manisrinivas]

i would not understand the flow of code and i need atleast pseudo code for this .can you help me

[Ashutosh Bhatt]

this is the psuedo code with all the necessary comments

what else you want

[s.manisrinivas]

bro ,i need to display the  result also in LCD

[Author]

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