stm32 accelerometer

erayurtseven · ‎2014-04-30

Posted on April 30, 2014 at 11:54

hi, I have a problem. I2C busy flag always set.

I am using I2C1 peripherel. this peripherel conected EEPROM, IO expander and Lis302dl

I think, problem is attaching EEPROM or IO expander.

how can I disconnect EEPROM and IO expander using software.

If this is not the problem, what is problem ?

my configuration codes:

GPIO_InitTypeDef GPIO_InitStructure;

I2C_InitTypeDef I2C_InitStructure;

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_OD; //GPIO_Mode_AF_PP;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_Init(GPIOB,&GPIO_InitStructure);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;

GPIO_Init(GPIOB,&GPIO_InitStructure);

I2C_Cmd(I2C1, ENABLE);

I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;

I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2;

I2C_InitStructure.I2C_OwnAddress1 = 0x00;

I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;

I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;

I2C_InitStructure.I2C_ClockSpeed = 100000;

I2C_Init(I2C1, &I2C_InitStructure);

codes for reading process:

unsigned char uc;

I2C_GenerateSTART(I2C1, ENABLE);

while (!(I2C_sr() & 0x0001)); // start condition generate edilene kkadar bekliyoz.

I2C_Send7bitAddress(I2C1, address, I2C_Direction_Transmitter);

while (!(I2C_sr() & 0x0002)); //Addr sent olana kadan bekle

I2C_SendData(I2C1,cmd);

while (!(I2C_sr() & 0x00000004)); /* Wait until BTF bit set */

I2C_GenerateSTART(I2C1, ENABLE);

while (!(I2C_sr() & 0x0001)); // start condition generate edilene kkadar bekliyoz.

I2C_Send7bitAddress(I2C1, address,I2C_Direction_Receiver);

while (!(I2C_sr() & 0x0002)); //Addr sent olana kadan bekle

uc = I2C_ReceiveData(I2C1);

while (!(I2C_sr() & 0x00000040)); /* Wait until RxNE bit set */

I2C_GenerateSTOP(I2C1, ENABLE);

while (I2C_sr() & 0x00020000); /* Wait until BUSY bit reset */

return( uc );

stm322399 · ‎2014-04-30

Posted on April 30, 2014 at 12:12

Normally, you must read SR2 (to get the MSL flag) after SR1 returns with ADDR flag set.

I don't know if it will solve your issue. Otherwise, I see no reasons for EEPROM or IOEXP to disturb the communication with LIS302dl. Try to adapt this one to your needs:

static uint8_t IOEXP_read8(uint8_t regnum)
{
int maxloop = 1000000;
uint8_t value;
I2C_GenerateSTART(I2C1, ENABLE);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_SB) == RESET ) if (!maxloop--) goto error;
I2C_Send7bitAddress(I2C1, IOEXP_ADDR*2, I2C_Direction_Transmitter);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_ADDR) == RESET ) if (!maxloop--) goto error;
I2C_GetFlagStatus(I2C1, I2C_FLAG_MSL);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_TXE) == RESET ) if (!maxloop--) goto error;
I2C_SendData(I2C1, regnum);
I2C_AcknowledgeConfig(I2C1, DISABLE);
I2C_GenerateSTART(I2C1, ENABLE);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_SB) == RESET ) if (!maxloop--) goto error;
I2C_Send7bitAddress(I2C1, IOEXP_ADDR*2, I2C_Direction_Receiver);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_ADDR) == RESET ) if (!maxloop--) goto error;
I2C_GetFlagStatus(I2C1, I2C_FLAG_MSL);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_RXNE) == RESET ) if (!maxloop--) goto error;
value = I2C_ReceiveData(I2C1);
I2C_GenerateSTOP(I2C1, ENABLE);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY) == SET ) if (!maxloop--) goto error;
return value;
error:
LOG_ERROR();
return 0;
}

erayurtseven · ‎2014-04-30

Posted on April 30, 2014 at 18:45

thanks for quick reply

I am debugging my code, so I see current situation of I2C1 registers,

SR1 = 0x00;

SR2= 0x02; always

so, progrmam hangs

erayurtseven · ‎2014-04-30

Posted on April 30, 2014 at 22:00

still there are problem.

any suggestion ?

chen · ‎2014-05-01

Posted on May 01, 2014 at 12:49

Do you have an oscilloscope or logic analyser?

With I2C - it is a good idea to examine the bus.

(The problem may not be with your code)