C code for ATmega 16 SPI communication

[cipriqe]

Can anyone help me with SPI ?

 

[sau_sol]

atmega16 spi

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

 

[cipriqe]

atmega16 spi example

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

 

[sau_sol]

atmega spi tutorial

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

#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;
}

 

[cipriqe]

atmega spdr

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...

 

[sau_sol]

atmega 16 spi

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

 

[cipriqe]

atmega spi code

oki.. thank you...

 

[sakender]

atmega8 spi example

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

 

[jon34560]

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

 

[jon34560]

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...

 

[chicadulce19]

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!!

 

[sreejith4348]

Re: C code for ATmega 32 with ad7705 SPI communication

#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