Original question:
Tool/software: TI-RTOS
Hi,
I'm trying to getting data from MPU-6050 using TI-RTOS. I tried with different work arounds and debugged. Unfortunately "I2C_transfer(i2c, &i2cTransaction)" is always returning false.
I 've found code using non-RTOS. But I want to implement with RTOS.
Please help me in this issue.
Many Thanks in advance,
Yashwanth.
OK, I think I see the problem. The MPU-6050 register addresses and commands are 8 bit, not 16 bit. Here is what your code wrote:
It actually wrote 0x6B to register 0 and 0x80 to register 1 and 0x00 to register 2. It should look like this:
Now you see it read 0x40 from register 0x6B. Here are some simple modifications to your writeRegister and readRegister routines.
void writeRegister(I2C_Handle handle, uint16_t regAddr, uint16_t value)
{
uint8_t txBuffer[4];
I2C_Transaction i2cTransaction;
i2cTransaction.slaveAddress = MPU6050_I2C_ADDRESS;
/* Write to a 16-bit status register */
i2cTransaction.writeBuf = txBuffer;
i2cTransaction.writeCount = 2;
i2cTransaction.readCount = 0;
txBuffer[0] = regAddr & 0xFF; //LB Addr
txBuffer[1] = value & 0xFF;
if (!I2C_transfer(handle, &i2cTransaction)) {
GPIO_write(Board_LED2, Board_LED_ON);
System_abort("Bad I2C transfer!");
}
}
void readRegister(I2C_Handle handle,
uint16_t regAddr,
uint8_t *data,
size_t length)
{
uint8_t txBuffer[2];
I2C_Transaction i2cTransaction;
i2cTransaction.slaveAddress = MPU6050_I2C_ADDRESS;
/* Write to a 16-bit status register */
i2cTransaction.writeBuf = txBuffer;
i2cTransaction.readBuf = data;
i2cTransaction.writeCount = 1;
i2cTransaction.readCount = length;
txBuffer[0] = regAddr & 0xFF; //LB Addr
if (!I2C_transfer(handle, &i2cTransaction)) {
GPIO_write(Board_LED2, Board_LED_ON);
System_abort("Bad I2C transfer!");
}
}
Here is the code (lines added between "Board_initGPIO()" and "Board_initI2C()") that I added to resolve when the MPU6050 is holding SDA low.
int main(void)
{
Task_Params taskParams;
/* Call board init functions */
Board_initGeneral();
Board_initGPIO();
// Check that I2C SDA is not being held low
// If so, toggle I2C SCL until it is released
GPIOPinTypeGPIOInput(GPIO_PORTD_BASE, GPIO_PIN_1);
GPIOPinTypeGPIOOutput(GPIO_PORTD_BASE, GPIO_PIN_0);
while(GPIOPinRead(GPIO_PORTD_BASE, GPIO_PIN_1) != GPIO_PIN_1)
{
GPIOPinWrite(GPIO_PORTD_BASE, GPIO_PIN_0, 0);
GPIOPinWrite(GPIO_PORTD_BASE, GPIO_PIN_0, GPIO_PIN_0);
}
Board_initI2C();
SysCtlClockSet(SYSCTL_SYSDIV_4|SYSCTL_USE_PLL|SYSCTL_XTAL_16MHZ|
SYSCTL_OSC_MAIN);
/* Construct nfcLoad Task thread */
Task_Params_init(&taskParams);
taskParams.stackSize = TASKSTACKSIZE;
taskParams.stack = &task0Stack;
taskParams.instance->name = "imusensor";
taskParams.priority = 1;
Task_construct(&task0Struct, (Task_FuncPtr)imuTask, &taskParams, NULL);
GPIO_write(Board_LED0, Board_LED_ON);
System_printf("Starting the I2C example\nSystem provider is set to SysMin."
" Halt the target to view any SysMin contents in ROV.\n");
/* SysMin will only print to the console when you call flush or exit */
System_flush();
srand(0xBEA5);
/* Start BIOS */
BIOS_start();
return (0);
}
The pulse in SCL is so short that it is basically hidden by the trigger line but you can see that it causes the MPU6050 to let SDA go high.