Tiva I2C I2C_MASTER_ERR_ARB_LOST error

Caner Cuhac

Other Parts Discussed in Thread: ADS1015, TM4C123GH6PM

Hello,

I can't understand what is the reason of getting this error. Below you can find my code:

bool AdafruitTaskInit(void)
{

   SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD);
   GPIOPinConfigure(GPIO_PD0_I2C3SCL);
   GPIOPinConfigure(GPIO_PD1_I2C3SDA);
   GPIOPinTypeI2C(GPIO_PORTD_BASE, GPIO_PIN_1);
   GPIOPinTypeI2CSCL(GPIO_PORTD_BASE, GPIO_PIN_0); // special I2CSCL treatment for M4F devices

   SysCtlPeripheralEnable(SYSCTL_PERIPH_I2C3);
   SysCtlPeripheralReset(SYSCTL_PERIPH_I2C3);
   I2CMasterInitExpClk(I2C3_BASE, SysCtlClockGet(), false);
   SysCtlDelay(10000);

   testdata = ads1015_read_register(0x01);

...

uint16_t ads1015_read_register(uint8_t read_reg) {
   I2CMasterSlaveAddrSet(I2C3_BASE, ADS1015_ADDRESS, false); // false = write
   I2CMasterDataPut(I2C3_BASE, read_reg);
   I2CMasterControl(I2C3_BASE, I2C_MASTER_CMD_SINGLE_SEND);
   while(I2CMasterBusy(I2C3_BASE)){}
   error_code = I2CMasterErr(I2C3_BASE);
//   Here I get the error! I2C_MASTER_ERR_ARB_LOST = 16 = 0x10

...

One strange thing is that I can not see I2CMDR register loaded. After I2CMasterDataPut(I2C3_BASE, read_reg);

I am using CCSv5.5.0.00077 on Windows with J-Link debugger.

Here is a picture from registers:

http://i.hizliresim.com/M96AZM.png

Thanks in advance!

over 9 years ago

0 Amit Ashara over 9 years ago

TI__Guru**** 244380 points

Hello Caner,

Can you please mention which device (TM4C123, TM4C129) and whether it is a custom board or Launchpad?

Regards

Amit

0 Caner Cuhac over 9 years ago in reply to Amit Ashara

Prodigy 160 points

It is a custom board with tm4c123gh6pm.

0 Amit Ashara over 9 years ago in reply to Caner Cuhac

TI__Guru**** 244380 points

Hello Caner,

Thanks for the info.

1. The I2CMDR register cannot be read to check what was written. The register acts as a data entry point for the I2C Controller

2. Since it is a custom board, so some simple questions:

a> Are there any other masters on the I2C bus?

b> Are the Pull Up externally there on the board for I2C SCL and SDA?

c> If possible can you share the schematics?

Regards

Amit

0 Caner Cuhac over 9 years ago in reply to Amit Ashara

Prodigy 160 points

Hello again Amit,

I did not try to read the register. I was checking its content from the debugger screen. (You can see the link to the picture in my first post.)

Now I have solved the problem. The reason was just a loose cabling. Now it works just fine.

Thanks for your assistance anyway,

- Caner

0 Amit Ashara over 9 years ago in reply to Caner Cuhac

TI__Guru**** 244380 points

Hello Caner

I thought so as well (or missing pull up on SDA)

By the way, reading from the debugger window is also a read operation for the register. So even if the code does not read, keeping a register in refresh mode in the debugger window will have the same effect.

Regards

Amit

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Tiva I2C I2C_MASTER_ERR_ARB_LOST error