Trying to make the I2C Demo works without a terminal - get stuck

Lecat Yoann

Other Parts Discussed in Thread: TMP006, CC3200

Hi everyone,

I can't use Tera Term in the same time of dubugging my code on CCS for an unknown reason (it previously worked but now it just don't...)

Anyway I just want to collect data from the accelerometer (BMA222) and the temperature sensor (TMP006) in order to treat the data.

To verify if my code works fine I just use the register map window from CCS.

So, I have troubles in the use of providing function I2C_IF_WRITE and I2C_IF_READ.

I manage to read from the I2C base adresses (accelerometer : 0x18 and temperature sensor : 0x41)

but I cannot :

- Write in the registers of the slave (even by using the function ProcessWriteRegCommand())

Typically, what I do is :

int main()
{

unsigned char aucDataBuf[8] ;
unsigned char ucDevAddr = 0x18
unsigned char ucLenRD = 8;

BoardInit();

PinMuxConfig();

/*
* ACCELEROMETER READING
*/

//
// I2C Init
//
I2C_IF_Open(I2C_MASTER_MODE_FST);

iRetVal = I2C_IF_Read(ucDevAddr, aucDataBuf, ucLenRD); // first read attempt : iRetVal = SUCCESS

char data_wr[8] = {0x01, 0x02,0x01, 0x02,0x01, 0x02,0x01, 0x02}; // non sens data for test

iRetVal = I2C_IF_Write(ucDevAdd,data_wr,ucLenWR, false); // writting attempt : iRetVal = SUCCESS

iRetVal = I2C_IF_Read(ucDevAddr, aucDataBuf, ucLenRD); // second read attempt : iRetVal = SUCCESS

return 0;

}

My code seems very simple to me, but no need to say I am quite new with I2C communication.

Also what I don't understand is :

- How can it works with 8-bits adresses provided in parameters of I2C_IF_READ & I2C_IF_WRITE functions ?

Shoudn't it be " I2C_IF_Read(ucDevAddr>>1, aucDataBuf, ucLenRD)" ? (it returns error)

Kind regards,

Yoann

over 9 years ago

0 David Bai over 9 years ago

TI__Intellectual 1835 points

Hi, Lecat Yoann

1. Tera Term doesn't work?

Answer: Do you make sure that the Port and the baud rate of Tera Term are right?

Does Tera Term work when you debug other examples?

2.You can see the Register Map in the datasheet of TMP006 and BMA222. For example, the Register Map of TMP006 is as below.

We can see that the ucRegOffset of Tambient is 0x01h, so we can use the function I2C_IF_WRITE and I2C_IF_READ as following (Just give a example about collectting data from the temperature sensor (TMP006) ):

int
ProcessReadRegTem()
{
unsigned char ucDevAddr = 0x41;

unsigned char ucRegOffset = 0x01;

unsigned char ucLenRD = 2;

RET_IF_ERR(I2C_IF_Write(ucDevAddr,&ucRegOffset,1,0));

//
// Read the specified length of data
//
RET_IF_ERR(I2C_IF_Read(ucDevAddr, &aucRdDataBuff[0], ucLenRD));

UART_PRINT("I2C Read Temperature complete\n\r");

//
// Display the buffer over UART on successful readreg
//
DisplayBuffer(aucRdDataBuff, ucLenRD);

return SUCCESS;
}

Datasheet of temperature sensor (TMP006):

TMP006datasheet.pdf

Datasheet of accelerometer (BMA222) :

BMA222 datasheet.pdf

0 David Bai over 9 years ago

TI__Intellectual 1835 points

Hi, Lecat Yoann

Another suggestion, please refer to the example: out_of_box, maybe it's helpful to you.

0 Lecat Yoann over 9 years ago in reply to David Bai

Intellectual 460 points

Hi David Bai !

Thanks for for this complete response.

I have already overcame the problems I had, but your response should works perfectly

and focused completely on the problem I ask help for.

My problems were :

1. Can't connect terminal while uploading the code onto cc3200 on CCS.

2. Can't read & write with API functions given in I2C_DEMO.

solutions :

Problem 1 :

Very simple, I was connecting the terminal before (or during) the code uploading on the cc3200 target on CCS.

In my case, I have to wait for the code uploading to be finished BEFORE connecting the terminal, then I can

connect the terminal and run the code step by step or full run (in debug mode).

Problem 2 :

For my use, I have modified the given API function in the main file of I2C_DEMO project.

Obviously I still use the I2C_write() & I2C_read() functions, now it works perfectly (see code below).

One issue I overcame (by testing) was that if you try to write '1' on a reserved bit, all the write operation

will be avorted, you have to write '0' on these bit positions.

Code that is working :

/*READ OPERATION TO A SPECIFIED REGISTER ADRESS*/

unsigned char ucDevAddr=0x18;//adresse I2C 0x18 = Accéléromètre

unsigned char ucRegOffset = 0x00;//offset voltage data

unsigned char ucRdLen = 2;

BoardInit();//init Board

PinMuxConfig();//Pins Configure

I2C_IF_Open(I2C_MASTER_MODE_FST);//Activation liaison I2C mode fast

iRetVal = I2C_IF_Write(ucDevAddr,&ucRegOffset,1,0);

iRetVal = I2C_IF_Read(ucDevAddr, &dataBuffVobj[0], ucRdLen);

/*WRITE OPERATION TO A SPECIFIED REGISTER ADRESS*/

unsigned char ucDevAddr=0x41;//adresse I2C 0x41 = Capteur Température

unsigned char ucRegOffset = 0x01;//offset temp data

unsigned char ucRdLen = 2;

BoardInit();//init Board

PinMuxConfig();//Pins Configure

I2C_IF_Open(I2C_MASTER_MODE_FST);//Activation liaison I2C mode fast

I2C_IF_Write(ucDevAddr,&aucDataBuf[0],ucWrLen,0);

So this is exactly the code you wrote in your response ...

I put this here in the case someone have same issue than me : )

But now I have issues for SPI communication with external sensors ...

If someone can help me I will be very greatfull, here is my post

: https://e2e.ti.com/support/wireless_connectivity/simplelink_wifi_cc31xx_cc32xx/f/968/p/497164/1798540#1798540

Thanks,

Yoann

0 Lecat Yoann over 9 years ago in reply to Lecat Yoann

Intellectual 460 points

Sorry for double post, here are the complete WRITE/READ function I use for I2C com :

//****************************************************************************
//
// store data stored in specified register/registers in dataBuffReg
//
//****************************************************************************
int
ProcessGetRegister(unsigned char * ucDevAddr,
unsigned char * dataBuffReg,
unsigned char * Offsets)
{
int i=0;
unsigned char ucRdLen = 1;// un octet
unsigned char tabtemp[sizeof(Offsets)-1];

while (i<sizeof(Offsets)-1) // copie des offsets dans var locale pour éviter //les problèmes de pointeurs
{
tabtemp[i] = Offsets[i];
i++;
}

int iRetVal;
i=0;

while(i<sizeof(Offsets)-1)//Lecture des données à tous les offsets spécifiés
{

iRetVal = I2C_IF_Write(*ucDevAddr,&tabtemp[i],1,0);

iRetVal = I2C_IF_Read(*ucDevAddr, &dataBuffReg[i], ucRdLen);

i++;

}

return iRetVal; //Retourne 0 pour succes ou -1 pour erreur
}

//****************************************************************************
//
// Write data stored in specified register/registers
//
//****************************************************************************

int
ProcessWriteRegCommand(unsigned char * ucDevAddr,
unsigned char * ucRegOffset,
unsigned char * data)
{

unsigned char ucWrLen = sizeof(*data)+1; //+1 pour l'offset
unsigned char aucDataBuf[2];
int iRetVal;
aucDataBuf[0] = *ucRegOffset;
aucDataBuf[1] = *data;

//
// Write the data values.
//
iRetVal = I2C_IF_Write(*ucDevAddr,&aucDataBuf[0],ucWrLen,0);

return iRetVal;
}

Have a good day,

Yoann

Wi-Fi

Wi-Fi forum

Trying to make the I2C Demo works without a terminal - get stuck