LPC1768 I2C Bus

[Nikolai110]

Hello, 

I'm programming data communication over an I2C bus on the LPC1768. To test the communication, I've looped back the I2C0 bus of the board with I2C1. The I2C0 is supposed to act as the master, and the I2C1 as the slave. However, when sending the data telegram, I always receive a "0x38 Arbitration lost in SLA+R/W or Data bytes" message in the status register, and the process terminates.

void I2C1_config(void)

{

LPC_SC->PCONP |=  (1 << 19);

LPC_PINCON->PINSEL1 &= ~0x000003C0;

  LPC_PINCON->PINSEL1 |= 0x000003C0;

LPC_I2C1->I2CONCLR = I2C_CON_FLAGS ; //Clear all flags

NVIC_EnableIRQ(I2C1_IRQn);

LPC_I2C1->I2ADR0= 0b10100000;

LPC_I2C1->I2MASK0=0xA0;

LPC_I2C1->I2CONSET |= I2C_CON_I2EN | I2C_CON_AA;  //I2C0 enable

LPC_I2C0->I2CONSET |= I2C_CON_STA;

}

void I2C0_config(void)             

{

LPC_SC->PCONP |= (1 << 7);

  LPC_PINCON->PINSEL1 &= ~0x03C00000;              

  LPC_PINCON->PINSEL1 |= 0x01400000;        // SDA und SCL

LPC_I2C0->I2CONCLR = I2C_CON_FLAGS ; //Clear I2C0CON Registers

LPC_I2C0->I2SCLL   = I2SCLL_SCLL; //DutyCicle

  LPC_I2C0->I2SCLH   = I2SCLH_SCLH;

//PCLK_I2C0=25MHz ,SCLH+SCLL=250, I2Cbitrate=PCLK_I2C0/(SCLH+SCLL)

NVIC_EnableIRQ(I2C0_IRQn); //Interrupt enable

LPC_I2C0->I2CONSET |= I2C_CON_I2EN; //I2C0 enable

I2C1_config();

}

this is my configuration yet

in my interrupthandler for I2C0 I only address the slave

void I2C0_IRQHandler(void){

uint8_t StatValue;

  StatValue = LPC_I2C0->I2STAT;

switch (StatValue){

case 0x08:

LPC_I2C0->I2DAT=state_vec[0];

LPC_I2C0->I2CONCLR=0x08;

break;

case 0x38:

LPC_I2C0->I2CONSET=0x20;

LPC_I2C0->I2CONCLR=0x08;

break;

case 0x68:

LPC_I2C0->I2CONSET=0x20;

LPC_I2C0->I2CONCLR=0x08;

break;

}

}

And this is my interrupthandler for I2C1

void I2C1_IRQHandler(void){

switch(LPC_I2C1->I2STAT)

{

case 0x60:

LPC_I2C1->I2CONSET=0x04;

LPC_I2C1->I2CONCLR=0x08;

break;

case 0x70:

LPC_I2C1->I2CONSET=I2C_CON_AA;

LPC_I2C1->I2CONSET=I2C_CON_SI;

break;

case 0x80:

break;

case 0xA0:

LPC_I2C1->I2CONSET=0x04;

LPC_I2C1->I2CONCLR=0x08;

}

}

After I address the slave and clear the I2C0 Interruptflag the I2C0 status is: 0x38 Arbitration lost in SLA+R/W or Data bytes

And the status of the I2C1 is: 0x60 Own SLA+W received; ACK returned

From there i have to restart the process cause of the 0x38 status. Can someone look into it and can tell me what i did wrong. I need to send a data byte after the addressing.

[Alice_Yang]

Hello @Nikolai110 

There is I2C demo under LPCopen, how about refer to the code.

Download from:

https://www.nxp.com/design/software/development-software/mcuxpresso-software-and-tools-/lpcopen-libr...   

"

I2C example

Example description
The I2C example shows how to use I2C interface in master and slave mode using
POLLING/INTERRUPT method.

"

BR

Alice