Rm46 i2c read from a slave device.

Hi Hassan,
Do you just want to read from one register address?

If this is the case then you don't want to define the DATA_COUNT 8 but instead should be just 1.

Also I think you want to swap the order of the below two APIs.

/* Send the Register Address */
i2cSendByte(i2cREG1, Slave_Register_address);
/* Transmit Start Condition */
i2cSetStart(i2cREG1);

Thankyou for your reply

i have this code for the TM4C123 and working good with th IMU. and i translated this code for the hercules rm46x

int32_t I2CReceive(int32_t slave_addr, int8_t reg)
{
//specify that we are writing (a register address) to the
//slave device
I2CMasterSlaveAddrSet(I2C3_BASE, slave_addr, false);

//specify register to be read
I2CMasterDataPut(I2C3_BASE, reg);

//send control byte and register address byte to slave device
I2CMasterControl(I2C3_BASE, I2C_MASTER_CMD_BURST_SEND_START);

//wait for MCU to finish transaction
while(I2CMasterBusy(I2C3_BASE));


//specify that we are going to read from slave device
I2CMasterSlaveAddrSet(I2C3_BASE, slave_addr, true);

//send control byte and read from the register we
//specified
I2CMasterControl(I2C3_BASE, I2C_MASTER_CMD_SINGLE_RECEIVE);

//wait for MCU to finish transaction
while(I2CMasterBusy(I2C3_BASE));

//return data pulled from the specified register
return I2CMasterDataGet(I2C3_BASE);
}



the translated code is

int32_t I2CReceive(int32_t slave_addr, int8_t reg)
{
i2cSetSlaveAdd(i2cREG1, slave_addr);
i2cSetDirection(i2cREG1, I2C_TRANSMITTER);
i2cSendByte(i2cREG1,reg);
i2cSetMode(i2cREG1, I2C_MASTER);
i2cSetStart(i2cREG1);
while(i2cIsBusBusy(i2cREG1) == true);

i2cSetSlaveAdd(i2cREG1, slave_addr);

i2cSetDirection(i2cREG1, I2C_RECEIVER);

i2cReceiveByte(i2cREG1);
printf("check: %i\n", 1);
i2cSetStart(i2cREG1);

while(i2cIsBusBusy(i2cREG1) == true);


return 0;

}


but it is stuck at i2cReceiveByte(i2cREG1) and doesnt go further...

Hi,
I cannot comment on the TM4C I2C. It is a different IP module from the one used in RM46x.

You might want to check out the example_i2c_pcf8570 as well. Please go to HalCoGen->Help->Help Topics->examples->example_i2c_pcf8570.

The RM46x i2C shares the same IP with the TI DSP device. Here is one document which contains flowcharts (from section 7.3) on how to transmit and receive for the master.

www.ti.com/.../spru175d.pdf

i checked this documentation.. and changed my code from this documentation and previous posts from the TI forum. I2CSAR and and I2CDXR receive correct addresses everytime but when i use the i2cReceiveByte function it got stuck there for infinite time.. I have tried lots of thing and didnt succeeded so far.. i am using this IMU github.com/.../tutorial

my code is...

int32_t I2CReceive(int32_t SLAVE_ADDRESS, int8_t reg)
{
while(i2cIsBusBusy (i2cREG1) == true);
i2cREG1->MDR = I2C_RESET_OUT;
i2cSetMode(i2cREG1, I2C_MASTER);
i2cSetSlaveAdd(i2cREG1, SLAVE_ADDRESS);
i2cSetDirection(i2cREG1, I2C_TRANSMITTER);
i2cSetCount(i2cREG1, 1);
i2cSetStart(i2cREG1);
while((i2cREG1->STR & (I2C_TX | I2C_ARDY)) == false); // To wait for the tx ready and register access ready
i2cSendByte(i2cREG1, reg);
// Start receiving the data from slave
// wait for ARDY before beginning the read phase of the transaction
while((i2cREG1->STR & I2C_ARDY) == false);
i2cREG1->MDR = I2C_RESET_OUT; // To set the MDR with I"C is out of reset

i2cSetMode(i2cREG1, I2C_MASTER);
i2cSetDirection(i2cREG1, I2C_RECEIVER);
i2cSetCount(i2cREG1, 1);
i2cSetStop(i2cREG1);
i2cSetStart(i2cREG1);
// To receive one byte
uint8 j;
for(j = 0; j < 1; j++)
{
while((i2cREG1->STR &(I2C_RX | I2C_ARDY)) == true);
sensTemp[j] = i2cREG1->DRR;
}

while(i2cIsBusBusy (i2cREG1) == true);
/* Wait until Stop is detected */
while(i2cIsStopDetected(i2cREG1) == false);
/* Clear the Stop condition */
i2cClearSCD(i2cREG1);
return sensTemp[0];
}



When i use the uint8 i2cReceiveByte() it got stuck and when i try to get data directly through the I2CDDR register it shows 0. so i think the data has not been copied from I2CRSR to I2CDRR everytime.

when i put the i2cSetStop(i2cREG1); after the loop(sensTemp[j] = i2cREG1->DRR;) then i get the DEFAULT values of the register from my IMU but get 0 from the data registers... and the value in the status register (I2CSTR) is 0x00002418 which means ICRRDY,ICXRDY,XSMT and NACKSNT is 1 ...

What do you mean the DEFAULT value? What value is it? Did you have a chance to use a scope to probe the SDA and SCL lines. Are you receiving the correct data on the bus? Do you have proper pull-up on the bus?