AVR Freaks

Hello,

 

you also can refer to this document :

 

Migration from the megaAVR® to AVR® Dx Microcontroller Families 

AN3731

ink online : http://ww1.microchip.com/downloads/en/Appnotes/Migration-from-megaAVR-to-AVR-DxMCU-Fam-DS00003731A.pdf

 

check the chapter 2.9 about TWI/I2C

 

best regards

Fabrice

Hello, 

I guess that you can assign the values you want to these identifiers.

They are just values to know on the fly the status of the I2C line.

 

by the way here is the code I use and works fine for me, with example of use included :

 

#define TWI0_BAUD(F_SCL)      ((((float)F_CPU / (float)F_SCL)) - 10 )

#define I2C_SCL_FREQ                                    100000

// I2C_base_ADDRESS                                     0b1000000  //address with 7 bits

#define I2C_DIRECTION_BIT_WRITE                         0
#define I2C_DIRECTION_BIT_READ                          1          

void I2C_0_init(void);
uint8_t I2C_0_start(uint8_t baseAddres, uint8_t directionBit);
uint8_t I2C_0_writingPacket (uint8_t data);
uint8_t I2C_0_receivingPacket(uint8_t acknack); 
void I2C_0_stop(void);

/*int main(void)
{
    I2C_0_init();
    
    while (1) 
    {
        I2C_0_start(I2C_BASE_ADDRESS, I2C_DIRECTION_BIT_READ);   //I2C_base_ADDRESS 7 bits
       
        result1 = I2C_0_receivingPacket(0);  //read with ack
        result2 = I2C_0_receivingPacket(1);  //read with nack
        I2C_0_stop();         
            
        I2C_0_start(I2C_BASE_ADDRESS, I2C_DIRECTION_BIT_WRITE);
        I2C_0_writingPacket(0x0D);  //write
        I2C_0_writingPacket(0x02);  //write
        I2C_0_stop();         
               
        _delay_ms(500);
    }
}*/

 void I2C_0_init(void)
{
    TWI0_MBAUD = (uint8_t)TWI0_BAUD(I2C_SCL_FREQ);	// set MBAUD register for I2C_SCL_Freq Hz
    TWI0_MCTRLA = TWI_ENABLE_bm;
    TWI0_MSTATUS = TWI_BUSSTATE_IDLE_gc;
}

uint8_t I2C_0_start(uint8_t baseAddres, uint8_t directionBit)
{
    TWI0_MADDR = (baseAddres<<1) + directionBit;
    while (!(TWI0_MSTATUS & (TWI_WIF_bm | TWI_RIF_bm)));    //wait for write or read interrupt flag
    if ((TWI0_MSTATUS & TWI_ARBLOST_bm)) return 0 ;         //return 0 if bus error or arbitration lost
    return !(TWI0_MSTATUS & TWI_RXACK_bm);                  //return 1 if slave gave an ack
}

uint8_t I2C_0_writingPacket(uint8_t data)
{
    while (!(TWI0_MSTATUS & TWI_WIF_bm));               //wait for write interrupt flag
    TWI0_MDATA = data;
    TWI0_MCTRLB = TWI_MCMD_RECVTRANS_gc;
    return (!(TWI0_MSTATUS & TWI_RXACK_bm));        //returns 1 if slave gave an ack
}

uint8_t I2C_0_receivingPacket(uint8_t acknack)      // 0 -> ack, else nack
{
    while (!(TWI0_MSTATUS & TWI_RIF_bm));               //wait for read interrupt flag
    uint8_t data = TWI0.MDATA;
    if (acknack == 0) {TWI0_MCTRLB = (TWI_ACKACT_ACK_gc  | TWI_MCMD_RECVTRANS_gc); }
    else                {TWI0_MCTRLB = (TWI_ACKACT_NACK_gc | TWI_MCMD_RECVTRANS_gc); }
    return data;
}

void I2C_0_stop(void)
{
    TWI0_MCTRLB = (TWI_ACKACT_NACK_gc | TWI_MCMD_STOP_gc);
}

Best regards

Fabrice

Please mark the solution - see Tip #5 in my signature, below:

Easiest way is to make a simple program that just scans through all 127 possible slave addresses - then the one which responds is the address of your slave.

 

Also remember the all-too-common confusion between "8-bit" and "7-bit" slave addresses:

 

https://www.avrfreaks.net/commen...

 

Even though "Arduino code" is C++ you often find that the authors are barely scratching the surface of what is possible in C++ and it will be very easy to convert it to plain C. The only possible stumbling block is where it calls on other "Arduino functions" like millis() or pinMode() or digitalWrite() or whatever. If it uses other bits of Arduino you will need to provide "C equivalents" for those.

 

(or another approach is simply to switch your entire project over to C++ anyway, anything written as C should work just as well as C++ then it can more easily integrate with stiff from Arduino - though you still need to consider how to replace the "other bits of Arduino" unless you simply want to do a complete "project import" as Andy suggested above.

 

PS googling for code (with added -Arduino to exclude anything related to Arduino) hits, for example:

 

http://randomport.com/doxygen/av...

 

Interesting looking API. Dunno yet where the actual code that is documented is located though!

 

EDIT: found the code:

 

https://github.com/matejx/avr_lib

 

That includes mfrc522.c and .h

 

Oh and the file includes:

This file was not written by me from scratch. It was adapted from code by Miguel Balboa at https://github.com/miguelbalboa/...

so probably worth a look too. 

"constructor instance" doesn't really have any meaning in C code.

 

Of course, you will have to "manually" do all the initialisation, memory allocation, etc that a C++ constructor would do.

 

it is giving timeout error.

So what debugging have you done to find out where it is timing-out, what it's waiting for when it times-out, etc ?