how to program use OpenCores I2C Master core in n2

some sample code

// I2C REGISTERS# define I2C_PRERLO 0# define I2C_PRERHI 1# define I2C_CTR 2# define I2C_TXR 3# define I2C_RXR 3# define I2C_CR 4# define I2C_SR 4

# define CTR_EN BIT7# define CTR_IEN BIT6

# define CR_STA BIT7# define CR_STO BIT6# define CR_RD BIT5# define CR_WR BIT4# define CR_NACK BIT3 // # define CR_NC1 BIT2# define CR_NC2 BIT1# define CR_IACK BIT0

# define SR_RXNACK BIT7# define SR_BUSY BIT6# define SR_AL BIT5# define SR_NC1 BIT4# define SR_NC2 BIT3# define SR_NC3 BIT2# define SR_TIP BIT1# define SR_IF BIT0

# define I2C_WR 0# define I2C_RD BIT0

int32_t i2c_init(void);

int32_t i2c_write_byte(uint8_t ctrl,uint8_t data,uint8_t *i2c_status);

int32_t i2c_read_byte(uint8_t ctrl,uint8_t *data,uint8_t *i2c_status);

// write and read time is about 25us for one byte

// we have to make timeout longer because of interrupts# define I2C_TIMEOUT (1000*50) // 40us (50 cputicks/us)

int32_t i2c_init(void)

{

IOWR(I2C_MASTER_0_BASE,I2C_CTR,0x00); // disable i2c

IOWR(I2C_MASTER_0_BASE,I2C_PRERLO,24); // sclk = 400khz

IOWR(I2C_MASTER_0_BASE,I2C_PRERHI,0); // sclk = 400khz

IOWR(I2C_MASTER_0_BASE,I2C_CTR,CTR_EN); // enable i2c

return 0;

};

int32_t i2c_write_byte(uint8_t ctrl,uint8_t data,uint8_t *i2c_status)

{

int32_t err=0;

uint8_t status=0;

uint32_t t1=0;

char temp[10];

IOWR(I2C_MASTER_0_BASE,I2C_TXR,data); //

IOWR(I2C_MASTER_0_BASE,I2C_CR,ctrl | CR_WR); //

status=IORD(I2C_MASTER_0_BASE,I2C_SR);

alt_timestamp_start();

while(!(status&SR_IF)) {

status=IORD(I2C_MASTER_0_BASE,I2C_SR);

t1=alt_timestamp();

if(t1>I2C_TIMEOUT)

{

printf("***ERROR I2C write byte timeout:status:0x%02x %s\r\n",status,binTostr(temp,status));

err=-1;

break;

}

}

if(status&SR_RXNACK)

{

printf("***ERROR I2C write byte ack failed:0x%02x %s\r\n",status,binTostr(temp,status));

err=-1;

}

// printf("I2C write byte time:%05d\r\n",t1/50);

IOWR(I2C_MASTER_0_BASE,I2C_CR,CR_IACK); //

*i2c_status=status;

return err;

}

// normally ctrl = CR_ACK

int32_t i2c_read_byte(uint8_t ctrl,uint8_t *data,uint8_t *i2c_status)

{

int32_t err=0;

uint8_t status=0;

uint32_t t1=0;

char temp[10];

IOWR(I2C_MASTER_0_BASE,I2C_CR,ctrl | CR_RD);

status=IORD(I2C_MASTER_0_BASE,I2C_SR);

alt_timestamp_start();

while(!(status&SR_IF)) {

status=IORD(I2C_MASTER_0_BASE,I2C_SR);

t1=alt_timestamp();

if(t1>I2C_TIMEOUT)

{

printf("***ERROR I2C read byte timeout:status:0x%02x %s\r\n",status,binTostr(temp,status));

err=-1;

break;

}

}

// printf("I2C read byte time:%05d\r\n",t1/50);

IOWR(I2C_MASTER_0_BASE,I2C_CR,CR_IACK); //

*data=IORD(I2C_MASTER_0_BASE,I2C_RXR);

*i2c_status=status;

return err;

}