Thread: C code for ATmega 16 SPI communication

Can anyone help me with SPI ?

what is the problem?
just tell it lot of people will help you

I want an example of program... I want to comunicate with an Convertor Sigma Delta

here is the program for SPI
I used this code for all of my programs

Code:

#include <avr/io.h>


void InitSPI(void)
{
DDRB = (1<<PB4)|(1<<PB5) | (1<<PB7);	 // Set MOSI , SCK , and SS output
SPCR = ( (1<<SPE)|(1<<MSTR) | (1<<SPR1) |(1<<SPR0));	// Enable SPI, Master, set clock rate fck/128  
}

void WriteByteSPI(unsigned char byte)
{
		
SPDR = byte;					//Load byte to Data register
while(!(SPSR & (1<<SPIF))); 	// Wait for transmission complete 

}

char ReadByteSPI(char addr)
{
	SPDR = addr;					//Load byte to Data register
	while(!(SPSR & (1<<SPIF))); 	// Wait for transmission complete 
	addr=SPDR;
	return addr;
}

ups... i do a mistake.. you can send me again ?

Added after 2 minutes:

i need to use miso mosi and sck to comunicate with it...

just copy the code and save it as a c file
or you can directly include this code in your program

first initialize the SPI and then use the read or write functions to access the content of the SPI

oki.. thank you...

Can anyone help me to interface spi sensor with pic OR at89c51 controller
?

Hello

I am having a problem with SPI communication between an Atmega32 and a ad7705(SPI). It works on one atmega32 chip that was produced in 2006 but it does not work on a handful of other atmega32 and atmega32a chips all produced in 2010.

I have tried various init parameters including reducing the clock rate to fck/128 all with the same result. I tried writing a small standalone program to test just the SPI function in the hope that there was some unintended effect from my main application.

The problem occurs when I wait for transmission:
while(!(SPSR & (1<<SPIF)));
This will loop forever. In my case i catch an error after 100000 iterations.

I also noticed that the problem occurs with no SPI devices attached after sending init commands. I would expect this. There must be something that is not correct with my code or fuses on these newer chips but i have no clue what it could be.

I am setting the PB5 and PB7 as output as well as by SS line. I am setting SPE and MSTR. I have tried various SPCR settings, all work on the 06 chip but not on the 2010 chips.

Does anyone have any thoughts on what i can try?

Thanks
Jon

I found the problem I posted today. I am driving the chip select on two SPI devices with IO lines and not using the SS PB4 line. I was able to write one byte to the SPI but the second write operation would never complete. I had to set the unused SS PB4 to out. Now it works. Funny how it worked on the chip from 06 though...

I am looking for some sample code for SPI communication between the ATMega328P (Master) and the ADE7763 (slave). I want my clock frequency to be fck/8. I want pin PB2 on the micro to be the designated SS connection to the ADE7763. For a test program, could somebody tell me how to read the temperature from the ADE7763. The temperature is on register 0x26 if I remember correctly from the datasheet.

Using the subroutines given above by sau_sol, how might I go about making a main program to do this?

Thanks!!

#include "avr/io.h"
#include <avr/interrupt.h>
#include "stdio.h"
#define F_CPU 11059200UL
#include <util/delay.h>

volatile double AdcOutput;
volatile unsigned char Temp,Temp1,Temp2;
volatile unsigned int k;

/************************************************
SPI INITIALISATION
*************************************************/

void SPIinit(void)
{
DDRB |= (1<<PB4)|(1<<PB5) | (1<<PB7); // Set MOSI , SCK , and SS output
SPCR |= ((1<<SPE)|(1<<MSTR)|(1<<SPR1)|(1<<SPR0)); // Enable SPI, Master, set clock rate fck/128

}

/************************************************
Writetoreg
*************************************************/

void Writetoreg( int byteword)
{
SPDR = byteword; // put the byteword into data register
while(!(SPSR & (1<<SPIF))); // Wait for transmission complete
byteword=SPDR; //just for clearing spif
}


/************************************************
Read
*************************************************/

unsigned int Read(char reglength)
{
int b;
for(b=0;b<reglength;b++)
{
SPDR = 0xFF;
while(!(SPSR &(1<<SPIF))); // Wait for transmission complete
if(b==0)
{
k=SPDR*256;
}
else
k=k+SPDR;
}

return k;
}

/************************************************
ADC INITIALISATION
*************************************************/

void ADCinit(void)
{
SPIinit();
Writetoreg(0x20); //Active channel is Ain(+) Ain(-), next operation as write to clock register
Writetoreg(0x0B); //(for clock register) master clock enabled, 2MHz Clock, set output rate to 20Hz*///0x08
Writetoreg(0x10); //Active channel is Ain1(+) Ain1(-), next operation as write to the setup register
Writetoreg(0x44); //(for setup register) gain = 1, bipolar mode, buffer off, clear FSYNC and perform a Self Calibration*/
}

/************************************************
Lcd out
*************************************************/

void lcdout(unsigned char Temp)
{
PORTA &= 0b11101111; // LOW TO PA4 'E' PIN

Temp1 = Temp; // EXAMPLE VALUE 25
Temp2 = Temp1;
Temp2 = Temp2 >>4; // ,, 02

Temp2 = Temp2 & 0x0F; // 1011 + 2

Temp = (PORTA);
Temp = Temp & 0xF0;
Temp = Temp | Temp2; // 1011 + 2
PORTA = Temp;


PORTA |= 0b00010000;
PORTA &= 0b11101111;


Temp = Temp1; // 25
Temp2 = Temp;
Temp2 = Temp2 & 0x0F; // 05
Temp = (PORTA); // 1011+5
Temp = Temp & 0xF0; // 1011+5
Temp = Temp | Temp2;
PORTA = Temp;
PORTA |= 0b00010000;
PORTA &= 0b11101111;
_delay_us (50);
}
/************************************************
lcd initialisation
*************************************************/

void LcdInit(void)
{
DDRA = 0xFF;
PORTA &= 0b11011111;
_delay_ms (20);
lcdout(0x38);
_delay_ms (05);
lcdout(0x38);
_delay_ms (100);
lcdout(0x38);
_delay_ms (02);
lcdout(0x28);
_delay_ms (02);
lcdout(0x08);
_delay_ms (02);
lcdout(0x01);
_delay_ms (02);
lcdout(0x06);
_delay_ms (02);
lcdout(0x0F);
_delay_ms (02);
lcdout(0x0C);
_delay_ms (02);
}


void calculate(volatile double data)
{
volatile double data2;

data = data * 2.5 /65535;

Temp = data;
lcdout(Temp|0x30);
lcdout('.');

Temp = data*100;
Temp =(Temp/10)%10;
lcdout(Temp|0x30);

Temp = data*100;
Temp =(Temp%10);
lcdout(Temp|0x30);

data2 = data*1000;
Temp =((int)data2%10);
lcdout(Temp|0x30);

data = data*10000;
Temp =((int)data%10);
lcdout(Temp|0x30);

}
void display_number(volatile long num)
{
int num3;

num3=num/10000;
lcdout(num3|0x30);
num =num%10000;

num3 =num/1000;
lcdout(num3|0x30);
num =(int)num%1000;

num3 =num/100;
lcdout(num3|0x30);
num =(int)num%100;

num3 =num/10;
lcdout(num3|0x30);
num3 =(int)num%10;

lcdout(num3|0x30);
}

/************************************************
Main loop
*************************************************/

int main()
{
DDRA = 0xFF; //Config DDRA as O/P for LCD display

DDRC = 0x40; //Config PC6 o/p for laser
PORTC |= 0x40;

LcdInit(); //lcd initialization
ADCinit(); //adc initialization

for(;;)
{
do
{
Writetoreg(0x08);
Read(1);
}
while(k&0x80);
// read from adc
Writetoreg(0x38); //set the next operation for 16 bit read from the data register
AdcOutput = Read(2);
_delay_ms (1000);
PORTA &= 0b11011111;
lcdout(0x0C5);
PORTA |= 0b00100000;
calculate(AdcOutput);
}
return 0;
}


try this, good luck