RTOS/TM4C1294NCPDT: TM4C1294NCPDT

shimon leonardo lewkowicz

Prodigy 160 points

Part Number: TM4C1294NCPDT
Other Parts Discussed in Thread: EK-TM4C1294XL

Tool/software: TI-RTOS

hello

I use TM4C1294NCPDT

init i2c but can't see nothing in the scope.

//I2C0
//This function is for eewiki and is to be updated to handle any port

//enable I2C module
SysCtlPeripheralEnable(SYSCTL_PERIPH_I2C0);

//reset I2C module
SysCtlPeripheralReset(SYSCTL_PERIPH_I2C0);

//enable GPIO peripheral that contains I2C
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);

// Configure the pin muxing for I2C0 functions on port B2 and B3.
GPIOPinConfigure(GPIO_PB2_I2C0SCL);
GPIOPinConfigure(GPIO_PB3_I2C0SDA);

// Select the I2C function for these pins.
GPIOPinTypeI2CSCL(GPIO_PORTB_BASE, GPIO_PIN_2);
GPIOPinTypeI2C(GPIO_PORTB_BASE, GPIO_PIN_3);

// Enable and initialize the I2C0 master module. Use the system clock for
// the I2C0 module. The last parameter sets the I2C data transfer rate.
// If false the data rate is set to 100kbps and if true the data rate will
// be set to 400kbps.
///I2CMasterInitExpClk(I2C0_BASE, SysCtlClockGet(), false);
I2CMasterInitExpClk(I2C0_BASE, ui32SysClock, true);

//clear I2C FIFOs
HWREG(I2C0_BASE + I2C_O_FIFOCTL) = 80008000;

need help

thanks

over 6 years ago

0 Ralph Jacobi over 6 years ago

TI__Guru*** 135355 points

Hello Shimon,

1) Do you have pull-down resistors present on the I2C bus?

2) Where is your code for sending data?

0 shimon leonardo lewkowicz over 6 years ago in reply to Ralph Jacobi

Prodigy 160 points

hello Ralph

uint8_t readI2C4(uint16_t device_address, uint16_t device_register ,uint16_t NumBytes)
{
//specify that we want to communicate to device address with an intended write to bus
I2CMasterSlaveAddrSet(I2C4_BASE, device_address, false);

//the register to be read
I2CMasterDataPut(I2C4_BASE, device_register);

//send control byte and register address byte to slave device
I2CMasterControl(I2C4_BASE, I2C_MASTER_CMD_SINGLE_SEND);

//wait for MCU to complete send transaction
while(I2CMasterBusy(I2C4_BASE));

//read from the specified slave device
I2CMasterSlaveAddrSet(I2C4_BASE, device_address, true);

for(counter = 0; counter < NumBytes; counter++)
{
//send control byte and read from the register from the MCU
I2CMasterControl(I2C4_BASE, I2C_MASTER_CMD_SINGLE_RECEIVE);

//wait while checking for MCU to complete the transaction
while(I2CMasterBusy(I2C4_BASE));
}

//Get the data from the MCU register and return to caller
return( I2CMasterDataGet(I2C4_BASE));
}

this is the send fcn

thanks

shimon

0 Ralph Jacobi over 6 years ago in reply to shimon leonardo lewkowicz

TI__Guru*** 135355 points

Hello Shimon,

And pull-ups? Are those present on the bus either on the LaunchPad or on the slave device that is connected to the LaunchPad?

0 Ralph Jacobi over 6 years ago in reply to shimon leonardo lewkowicz

TI__Guru*** 135355 points

Hello Shimon,

Just noticed at second look of your code... you initialize I2C0, but you are trying to send and receive with I2C4. This would not work. You need to initialize and send with the same I2C module. So either I2C0 for init and send, or I2C4 for init and send.

0 shimon leonardo lewkowicz over 6 years ago in reply to Ralph Jacobi

Prodigy 160 points

Hello Ralph
I have init i2c 0 1 2 & 4.

the same way that I init i2c0.

the pull- ups are not implemented in the launchpad??

0 Chester Gillon over 6 years ago in reply to shimon leonardo lewkowicz

Guru 92251 points

shimon leonardo lewkowicz said:
the pull- ups are not implemented in the launchpad??

Not sure which launchpad you are using, but looking at the schematic for the EK-TM4C1294XL in the User Guide I can't see any pull-ups on the I2C pins on the launchpad itself.

I.e. external pull-ups are required.

0 shimon leonardo lewkowicz over 6 years ago in reply to Chester Gillon

Prodigy 160 points

good morning

ok

I will fix the pull-ups as required.

I need to know if my code is OK.

thanks

shimon

0 Ralph Jacobi over 6 years ago in reply to shimon leonardo lewkowicz

TI__Guru*** 135355 points

Hello Shimon,

You'd need to post the proper initialization code for the I2C you are having the issue with sending from, from there I could test the code out.

The pull-up's are the most important point here though, your code could be perfect and without pull-up's it wouldn't work.

Also for starting to get the system working, I would recommend using 100kbps first. Use the fast mode for 400kbps after we confirm you have the I2C interface working in case the speed change causes any issues from a hardware perspective.

0 shimon leonardo lewkowicz over 6 years ago in reply to Ralph Jacobi

Prodigy 160 points

Hello Ralph

thank you very much for all your recommendations.

best regards

shimon

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RTOS/TM4C1294NCPDT: TM4C1294NCPDT