Problems with I2C1 and LIS302DL

bargaclau · ‎2009-04-13

Posted on April 13, 2009 at 09:04

bargaclau · ‎2011-05-17

Posted on May 17, 2011 at 13:09

Hi,

I've a problem using a STM32101RBT6 I2C1 port and A LIS302 accelerometer.

The device answers, but the only value I receive when I read the 0x0F register ( Who am I) is 0x38 instead of 0x3B.

On the hardware side, everything seems ok. Pullpu resistors (4k7), the CS pin up and SDO down.

On the Sw side, I initialize the I2C1 this way:

I2C_InitTypeDef I2C_InitStructure;

/* Enable I2C1----------------------------------------------------*/

I2C_Cmd(I2C1, ENABLE);

/* I2C1 configuration ------------------------------------------------------*/

I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;

I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2;

I2C_InitStructure.I2C_OwnAddress1 = I2C1_SLAVE_ADDRESS7;

I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;

I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;

I2C_InitStructure.I2C_ClockSpeed = ClockSpeed;

I2C_Init(I2C1, &I2C_InitStructure);

and ask the device this way:

I2C_GenerateSTART(I2C1, ENABLE);

while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));

I2C_Send7bitAddress(I2C1, DEVICE_WRITE, I2C_Direction_Transmitter);

while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));

I2C_SendData(I2C1, register_name);

while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));

I2C_GenerateSTART(I2C1, ENABLE);

while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));

I2C_Send7bitAddress(I2C1, DEVICE_READ, I2C_Direction_Transmitter);

while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));

in_byte = I2C_ReceiveData(I2C1);

I2C_GenerateSTOP(I2C1, ENABLE);

return(in_byte);

Always the same value...WHY??? Where am I doing a mistake?

Thanks,

Claudio

bargaclau · ‎2011-05-17

Posted on May 17, 2011 at 13:09

Hi everyone,

the nighttime sometimes helps...and I've found some errors in my code, expecially about the device addressing and the communication direction.

I have another problem now, that I solved usnig a tip suggested by Brj in this topic

http://www.st.com/mcu/forums-cat-6701-23.html

every byte read I deinit and reinit I2C. I'm sure that is not efficent, but now it works.

If anyone has a suggestion...

here is the code:

I2C_GenerateSTART(I2C1, ENABLE);

while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));

Dly15us();

I2C_Send7bitAddress(I2C1, DEVICE_ADDR, I2C_Direction_Transmitter);

while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));

Dly15us();

I2C_SendData(I2C1, register_name);

while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));

Dly15us();

I2C_GenerateSTART(I2C1, ENABLE);

while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));

Dly15us();

I2C_Send7bitAddress(I2C1, DEVICE_ADDR, I2C_Direction_Receiver);

while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED));

// Inactive ACK

I2C_AcknowledgeConfig(I2C1, DISABLE);

Dly15us();

while( !I2C_CheckEvent( I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED ) ); // EV7

in_byte = I2C_ReceiveData(I2C1);

// while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED));

I2C_GenerateSTOP(I2C1, ENABLE);

// active ACK

I2C_AcknowledgeConfig(I2C1, ENABLE);

I2C_DeInit(I2C1);

InitI2C();

return(in_byte);

bye ,

Claudio