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I2C Master Bus Collision while sending regaddress to IMU sensor boards

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sachukol

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I am having issues with I2C communications protocol while communicating with gyroscope that is part of an IMU breakout board. I am able to initialize and start transfer for I2C between PIC32 and IMU but when sending in the regaddress byte it runs into a master bus collision. I have included the following code. If you could please help me resolve this issue it would be greatly helpful for my project.

Code C - [expand]
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/* 
 * File:   imumain.c
 * Author: harsh
 *
 * Created on April 14, 2012, 10:42 AM
 */
 
//#include <stdio.h>
//#include <stdlib.h>
#include <plib.h>
#include <stdint.h>
#include <stdbool.h>
 
 
#define SystemClock() (80000000)
#define PeripheralClock()  (GetSystemClock()/(1<<OSCCONbite.PBDIV))
 
#define I2C_CLOCK_FREQ 100000
#define ACCEL_ADDRESS 0x53
#define MAG_ADDRESS 0x34
 
 
BOOL StartTransfer(BOOL, I2C_MODULE);
BOOL TransmitOneByte(UINT8, I2C_MODULE);
BOOL I2CSingleByteRead(UINT8, UINT8, UINT8*, I2C_MODULE);
BOOL ReceiveOneByte(UINT8*, I2C_MODULE );
VOID StopTransfer(I2C_MODULE);
/*
 * 
 */
int main(void) {
 
//#ifndef PIC32_STARTER_KIT
//    DDPCONbits.JTAGEN = 0;
//#endif
 
    UINT32 actualClock;
 
    //CONFIGURE I2C
 
    I2CConfigure(I2C1, I2C_ENABLE_SLAVE_CLOCK_STRETCHING|I2C_ENABLE_HIGH_SPEED);
    if ( abs(actualClock-I2C_CLOCK_FREQ) > I2C_CLOCK_FREQ/10 )
    {
        DBPRINTF("Error: I2C1 clock frequency (%u) error exceeds 10%%.\n", (unsigned)actualClock);
    }
    I2CEnable(I2C1,TRUE);
    I2CClearStatus(I2C1,I2C_TRANSMITTER_FULL);
    UINT8 tOutData = 0X00;
    BOOL bothWork = TRUE;
 
    if (I2CSingleByteRead(MAG_ADDRESS,0X00, &tOutData, I2C1))
    {
        if (tOutData != 34)
            bothWork = FALSE;
    }
 
 
    return (EXIT_SUCCESS);
}
 
/*******************************************************************************
  Function:
    BOOL StartTransfer( BOOL restart )
 
  Summary:
    Starts (or restarts) a transfer to/from the EEPROM.
 
  Description:
    This routine starts (or restarts) a transfer to/from the EEPROM, waiting (in
    a blocking loop) until the start (or re-start) condition has completed.
 
  Precondition:
    The I2C module must have been initialized.
 
  Parameters:
    restart - If FALSE, send a "Start" condition
            - If TRUE, send a "Restart" condition
 
  Returns:
    TRUE    - If successful
    FALSE   - If a collision occured during Start signaling
 
  Example:
    <code>
    StartTransfer(FALSE);
    </code>
 
  Remarks:
    This is a blocking routine that waits for the bus to be idle and the Start
    (or Restart) signal to complete.
  *****************************************************************************/
 
BOOL StartTransfer( BOOL restart, I2C_MODULE i2cselect )
{
    I2C_STATUS  status;
 
    // Send the Start (or Restart) signal
    if(restart)
    {
        I2CRepeatStart(i2cselect);
    }
    else
    {
        // Wait for the bus to be idle, then start the transfer
        while( !I2CBusIsIdle(i2cselect) );
 
        if(I2CStart(i2cselect) != I2C_SUCCESS)
        {
            DBPRINTF("Error: Bus collision during transfer Start\n");
            return FALSE;
        }
    }
 
    // Wait for the signal to complete
    do
    {
        status = I2CGetStatus(i2cselect);
 
    } while ( !(status & I2C_START) );
 
    return TRUE;
}
 
/*******************************************************************************
  Function:
    BOOL TransmitOneByte( UINT8 data )
 
  Summary:
    This transmits one byte to the EEPROM.
 
  Description:
    This transmits one byte to the EEPROM, and reports errors for any bus
    collisions.
 
  Precondition:
    The transfer must have been previously started.
 
  Parameters:
    data    - Data byte to transmit
 
  Returns:
    TRUE    - Data was sent successfully
    FALSE   - A bus collision occured
 
  Example:
    <code>
    TransmitOneByte(0xAA);
    </code>
 
  Remarks:
    This is a blocking routine that waits for the transmission to complete.
  *****************************************************************************/
 
BOOL TransmitOneByte( UINT8 data, I2C_MODULE i2cselect )
{
    //I2C_RESULT result;
    // Wait for the transmitter to be ready
    I2C_STATUS status;
    while(!I2CTransmitterIsReady(i2cselect));
 
    // Transmit the byte
    if( I2CSendByte(i2cselect, data) == I2C_MASTER_BUS_COLLISION)
    {
        DBPRINTF("Error: I2C Master Bus Collision\n");
        return FALSE;
    }
 
    status = I2CGetStatus(I2C1);
    // Wait for the transmission to finish
    while(!I2CTransmissionHasCompleted(i2cselect));
    //Verify that the byte was acknowledged
    if (!I2CByteWasAcknowledged(i2cselect))
    {
        DBPRINTF("Error: Sent byte was not acknowledged\n");
        return FALSE;
    }
 
    return TRUE;
}
 
/*******************************************************************************
  Function:
    BOOL ReceiveOneByte( UINT8* data )
 
  Summary:
     Get one byte of data.
 
  Description:
    This routine checks for recieve overflow if not if data is available get
 *  byte.
 
  Precondition:
    The I2C module must have been initialized & a transfer started.
 
  Parameters:
    None.
 
  Returns:
    None.
 
  Example:
    <code>
    if(!RecieveOneByte(data))
 *    Success = FALSE;
    </code>
 
  Remarks:
    This is a blocking routine that waits for the Stop signal to complete.
  *****************************************************************************/
BOOL ReceiveOneByte(UINT8* data, I2C_MODULE i2cselect)
{
    if (!I2CReceiverEnable(I2C1, TRUE) == I2C_RECEIVE_OVERFLOW)
        return FALSE;
    else
    {
        while(!I2CReceivedDataIsAvailable(I2C1));
        *(data) = I2CGetByte(I2C1);
    }
 
    return TRUE;
}
/*******************************************************************************
  Function:
    void StopTransfer( void )
 
  Summary:
    Stops a transfer to/from the EEPROM.
 
  Description:
    This routine Stops a transfer to/from the EEPROM, waiting (in a
    blocking loop) until the Stop condition has completed.
 
  Precondition:
    The I2C module must have been initialized & a transfer started.
 
  Parameters:
    None.
 
  Returns:
    None.
 
  Example:
    <code>
    StopTransfer();
    </code>
 
  Remarks:
    This is a blocking routine that waits for the Stop signal to complete.
  *****************************************************************************/
 
void StopTransfer(I2C_MODULE i2c )
{
    I2C_STATUS  status;
 
    // Send the Stop signal
    I2CStop(i2c);
 
    // Wait for the signal to complete
    do
    {
        status = I2CGetStatus(i2c);
 
    } while ( !(status & I2C_STOP) );
 
}
 
BOOL I2CSingleByteRead(UINT8 target, UINT8 regaddress, UINT8* output, I2C_MODULE i2c)
{
    if(!StartTransfer(FALSE, i2c))
        return FALSE;
    I2C_7_BIT_ADDRESS SlaveAddress;
    I2C_FORMAT_7_BIT_ADDRESS(SlaveAddress, target, I2C_WRITE);
    if(!TransmitOneByte(SlaveAddress.byte, i2c))
        return FALSE;
    if(!TransmitOneByte(regaddress, i2c))
        return FALSE;
    if(!StartTransfer(TRUE, i2c))
        return FALSE;
    I2C_FORMAT_7_BIT_ADDRESS(SlaveAddress, target, I2C_READ);
    if(!TransmitOneByte(SlaveAddress.byte, i2c))
        return FALSE;
    if (!ReceiveOneByte(output,i2c))
        return FALSE;
    //Send NAK and wait to finish
    I2CAcknowledgeByte(i2c,FALSE);
    I2CAcknowledgeHasCompleted(i2c);
    StopTransfer(i2c);
    return TRUE;
}
 
Last edited by a moderator:

Before posting tons of code, you shoúld tell what you are trying to achieve. Why you have two masters in your system? If you have, are both prepared for multimaster operation?

There are code tags at Edaboard to improve code readability, by the way.
 

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