C++ I2CMasterBaseValid函数代码示例

//*****************************************************************************
//
//! Controls the state of the I2C Master module.
//!
//! \param ulBase is the base address of the I2C Master module.
//! \param ulCmd command to be issued to the I2C Master module.
//!
//! This function is used to control the state of the Master module send and
//! receive operations.  The \e ucCmd parameter can be one of the following
//! values:
//!
//! - \b I2C_MASTER_CMD_SINGLE_SEND
//! - \b I2C_MASTER_CMD_SINGLE_RECEIVE
//! - \b I2C_MASTER_CMD_BURST_SEND_START
//! - \b I2C_MASTER_CMD_BURST_SEND_CONT
//! - \b I2C_MASTER_CMD_BURST_SEND_FINISH
//! - \b I2C_MASTER_CMD_BURST_SEND_ERROR_STOP
//! - \b I2C_MASTER_CMD_BURST_RECEIVE_START
//! - \b I2C_MASTER_CMD_BURST_RECEIVE_CONT
//! - \b I2C_MASTER_CMD_BURST_RECEIVE_FINISH
//! - \b I2C_MASTER_CMD_BURST_RECEIVE_ERROR_STOP
//! - \b I2C_MASTER_CMD_QUICK_COMMAND
//! - \b I2C_MASTER_CMD_HS_MASTER_CODE_SEND
//!
//! \return None.
//
//*****************************************************************************
void
I2CMasterControl(unsigned long ulBase, unsigned long ulCmd)
{
    //
    // Check the arguments.
    //
    ASSERT(I2CMasterBaseValid(ulBase));
    ASSERT((ulCmd == I2C_MASTER_CMD_SINGLE_SEND) ||
           (ulCmd == I2C_MASTER_CMD_SINGLE_RECEIVE) ||
           (ulCmd == I2C_MASTER_CMD_BURST_SEND_START) ||
           (ulCmd == I2C_MASTER_CMD_BURST_SEND_CONT) ||
           (ulCmd == I2C_MASTER_CMD_BURST_SEND_FINISH) ||
           (ulCmd == I2C_MASTER_CMD_BURST_SEND_ERROR_STOP) ||
           (ulCmd == I2C_MASTER_CMD_BURST_RECEIVE_START) ||
           (ulCmd == I2C_MASTER_CMD_BURST_RECEIVE_CONT) ||
           (ulCmd == I2C_MASTER_CMD_BURST_RECEIVE_FINISH) ||
           (ulCmd == I2C_MASTER_CMD_BURST_RECEIVE_ERROR_STOP) ||
           (ulCmd == I2C_MASTER_CMD_QUICK_COMMAND) ||
           (ulCmd == I2C_MASTER_CMD_HS_MASTER_CODE_SEND));

    //
    // Send the command.
    //
    HWREG(ulBase + I2C_O_MCS) = ulCmd;
}

//*****************************************************************************
//
//! Registers an interrupt handler for the I2C module.
//!
//! \param ulBase is the base address of the I2C Master module.
//! \param pfnHandler is a pointer to the function to be called when the
//! I2C interrupt occurs.
//!
//! This function sets the handler to be called when an I2C interrupt occurs.
//! This function enables the global interrupt in the interrupt controller;
//! specific I2C interrupts must be enabled via I2CMasterIntEnable() and
//! I2CSlaveIntEnable().  If necessary, it is the interrupt handler's
//! responsibility to clear the interrupt source via I2CMasterIntClear() and
//! I2CSlaveIntClear().
//!
//! \sa IntRegister() for important information about registering interrupt
//! handlers.
//!
//! \return None.
//
//*****************************************************************************
void
I2CIntRegister(unsigned long ulBase, void (*pfnHandler)(void))
{
    unsigned long ulInt;

    //
    // Check the arguments.
    //
    ASSERT(I2CMasterBaseValid(ulBase));

    //
    // Determine the interrupt number based on the I2C port.
    //
    ulInt = I2CIntNumberGet(ulBase);

    //
    // Register the interrupt handler, returning an error if an error occurs.
    //
    IntRegister(ulInt, pfnHandler);

    //
    // Enable the I2C interrupt.
    //
    IntEnable(ulInt);
}

//*****************************************************************************
//
//! Unregisters an interrupt handler for the I2C module.
//!
//! \param ulBase is the base address of the I2C Master module.
//!
//! This function clears the handler to be called when an I2C interrupt
//! occurs.  This function also masks off the interrupt in the interrupt r
//! controlle so that the interrupt handler no longer is called.
//!
//! \sa IntRegister() for important information about registering interrupt
//! handlers.
//!
//! \return None.
//
//*****************************************************************************
void
I2CIntUnregister(unsigned long ulBase)
{
    unsigned long ulInt;

    //
    // Check the arguments.
    //
    ASSERT(I2CMasterBaseValid(ulBase));

    //
    // Determine the interrupt number based on the I2C port.
    //
    ulInt = I2CIntNumberGet(ulBase);

    //
    // Disable the interrupt.
    //
    IntDisable(ulInt);

    //
    // Unregister the interrupt handler.
    //
    IntUnregister(ulInt);
}

//*****************************************************************************
//
//! Sets the Master clock timeout value.
//!
//! \param ulBase is the base address of the I2C Master module.
//! \param ulValue is the number of I2C clocks before the timeout is asserted.
//!
//! This function enables and configures the clock low timeout feature in the
//! I2C peripheral.  This feature is implemented as a 12-bit counter, with the
//! upper 8-bits being programmable.  For example, to program a timeout of 20ms
//! with a 100kHz SCL frequency, \e ulValue would be 0x7d.
//!
//! \note Not all Stellaris devices support this function.  Please consult the
//! device data sheet to determine if this feature is supported.
//!
//! \return None.
//
//*****************************************************************************
void
I2CMasterTimeoutSet(unsigned long ulBase, unsigned long ulValue)
{
    //
    // Check the arguments.
    //
    ASSERT(I2CMasterBaseValid(ulBase));

    //
    // Write the timeout value.
    //
    HWREG(ulBase + I2C_O_MCLKOCNT) = ulValue;
}

//*****************************************************************************
//
//! Receives a byte that has been sent to the I2C Master.
//!
//! \param ulBase is the base address of the I2C Master module.
//!
//! This function reads a byte of data from the I2C Master Data Register.
//!
//! \return Returns the byte received from by the I2C Master, cast as an
//! unsigned long.
//
//*****************************************************************************
unsigned long
I2CMasterDataGet(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(I2CMasterBaseValid(ulBase));

    //
    // Read a byte.
    //
    return(HWREG(ulBase + I2C_O_MDR));
}

//*****************************************************************************
//
//! Disables the I2C master block.
//!
//! \param ulBase is the base address of the I2C Master module.
//!
//! This function disables operation of the I2C master block.
//!
//! \return None.
//
//*****************************************************************************
void
I2CMasterDisable(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(I2CMasterBaseValid(ulBase));

    //
    // Disable the master block.
    //
    HWREG(ulBase + I2C_O_MCR) &= ~(I2C_MCR_MFE);
}

//*****************************************************************************
//
//! Reads the state of the SDA and SCL pins.
//!
//! \param ulBase is the base address of the I2C Master module.
//!
//! This function returns the state of the I2C bus by providing the real time
//! values of the SDA and SCL pins.
//!
//! \note Not all Stellaris devices support this function.  Please consult the
//! device data sheet to determine if this feature is supported.
//!
//! \return Returns the state of the bus with SDA in bit position 1 and SCL in
//! bit position 0.
//
//*****************************************************************************
unsigned long
I2CMasterLineStateGet(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(I2CMasterBaseValid(ulBase));

    //
    // Return the line state.
    //
    return(HWREG(ulBase + I2C_O_MBMON));
}

//*****************************************************************************
//
//! Clears I2C Master interrupt sources.
//!
//! \param ulBase is the base address of the I2C Master module.
//! \param ulIntFlags is a bit mask of the interrupt sources to be cleared.
//!
//! The specified I2C Master interrupt sources are cleared, so that they no
//! longer assert.  This function must be called in the interrupt handler to
//! keep the interrupt from being triggered again immediately upon exit.
//!
//! The \e ulIntFlags parameter has the same definition as the \e ulIntFlags
//! parameter to I2CMasterIntEnableEx().
//!
//! \note Because there is a write buffer in the Cortex-M processor, it may
//! take several clock cycles before the interrupt source is actually cleared.
//! Therefore, it is recommended that the interrupt source be cleared early in
//! the interrupt handler (as opposed to the very last action) to avoid
//! returning from the interrupt handler before the interrupt source is
//! actually cleared.  Failure to do so may result in the interrupt handler
//! being immediately reentered (because the interrupt controller still sees
//! the interrupt source asserted).
//!
//! \return None.
//
//*****************************************************************************
void
I2CMasterIntClearEx(unsigned long ulBase, unsigned long ulIntFlags)
{
    //
    // Check the arguments.
    //
    ASSERT(I2CMasterBaseValid(ulBase));

    //
    // Clear the I2C master interrupt source.
    //
    HWREG(ulBase + I2C_O_MICR) = ulIntFlags;
}

//*****************************************************************************
//
//! Enables the I2C Master interrupt.
//!
//! \param ulBase is the base address of the I2C Master module.
//!
//! This function enables the I2C Master interrupt source.
//!
//! \return None.
//
//*****************************************************************************
void
I2CMasterIntEnable(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(I2CMasterBaseValid(ulBase));

    //
    // Enable the master interrupt.
    //
    HWREG(ulBase + I2C_O_MIMR) = 1;
}

//*****************************************************************************
//
//! Disables individual I2C Master interrupt sources.
//!
//! \param ulBase is the base address of the I2C Master module.
//! \param ulIntFlags is the bit mask of the interrupt sources to be disabled.
//!
//! This function disables the indicated I2C Master interrupt sources.  Only
//! the sources that are enabled can be reflected to the processor interrupt;
//! disabled sources have no effect on the processor.
//!
//! The \e ulIntFlags parameter has the same definition as the \e ulIntFlags
//! parameter to I2CMasterIntEnableEx().
//!
//! \return None.
//
//*****************************************************************************
void
I2CMasterIntDisableEx(unsigned long ulBase, unsigned long ulIntFlags)
{
    //
    // Check the arguments.
    //
    ASSERT(I2CMasterBaseValid(ulBase));

    //
    // Disable the master interrupt.
    //
    HWREG(ulBase + I2C_O_MIMR) &= ~ulIntFlags;
}

//*****************************************************************************
//
//! Transmits a byte from the I2C Master.
//!
//! \param ulBase is the base address of the I2C Master module.
//! \param ucData data to be transmitted from the I2C Master.
//!
//! This function places the supplied data into I2C Master Data Register.
//!
//! \return None.
//
//*****************************************************************************
void
I2CMasterDataPut(unsigned long ulBase, unsigned char ucData)
{
    //
    // Check the arguments.
    //
    ASSERT(I2CMasterBaseValid(ulBase));

    //
    // Write the byte.
    //
    HWREG(ulBase + I2C_O_MDR) = ucData;
}

//*****************************************************************************
//
//! Initializes the I2C Master block.
//!
//! \param ulBase is the base address of the I2C Master module.
//! \param ulI2CClk is the rate of the clock supplied to the I2C module.
//! \param bFast set up for fast data transfers.
//!
//! This function initializes operation of the I2C Master block by configuring
//! the bus speed for the master and enabling the I2C Master block.
//!
//! If the parameter \e bFast is \b true, then the master block is set up to
//! transfer data at 400 Kbps; otherwise, it is set up to transfer data at
//! 100 Kbps.  If Fast Mode Plus (1 Mbps) is desired, software should manually
//! write the I2CMTPR after calling this function.  For High Speed (3.4 Mbps)
//! mode, a specific command is used to switch to the faster clocks after the
//! initial communication with the slave is done at either 100 Kbps or
//! 400 Kbps.
//!
//! The peripheral clock is the same as the processor clock.  This value is
//! returned by SysCtlClockGet(), or it can be explicitly hard coded if it is
//! constant and known (to save the code/execution overhead of a call to
//! SysCtlClockGet()).
//!
//! This function replaces the original I2CMasterInit() API and performs the
//! same actions.  A macro is provided in <tt>i2c.h</tt> to map the original
//! API to this API.
//!
//! \return None.
//
//*****************************************************************************
void
I2CMasterInitExpClk(unsigned long ulBase, unsigned long ulI2CClk,
                    tBoolean bFast)
{
    unsigned long ulSCLFreq;
    unsigned long ulTPR;

    //
    // Check the arguments.
    //
    ASSERT(I2CMasterBaseValid(ulBase));

    //
    // Must enable the device before doing anything else.
    //
    I2CMasterEnable(ulBase);

    //
    // Get the desired SCL speed.
    //
    if(bFast == true)
    {
        ulSCLFreq = 400000;
    }
    else
    {
        ulSCLFreq = 100000;
    }

    //
    // Compute the clock divider that achieves the fastest speed less than or
    // equal to the desired speed.  The numerator is biased to favor a larger
    // clock divider so that the resulting clock is always less than or equal
    // to the desired clock, never greater.
    //
    ulTPR = ((ulI2CClk + (2 * 10 * ulSCLFreq) - 1) / (2 * 10 * ulSCLFreq)) - 1;
    HWREG(ulBase + I2C_O_MTPR) = ulTPR;

    //
    // Check to see if this I2C peripheral is High-Speed enabled.  If yes, also
    // choose the fastest speed that is less than or equal to 3.4 Mbps.
    //
    if(HWREG(ulBase + I2C_O_PP) & I2C_PP_HS)
    {
        ulTPR = ((ulI2CClk + (2 * 3 * 3400000) - 1) /
                (2 * 3 * 3400000)) - 1;
        HWREG(ulBase + I2C_O_MTPR) = I2C_MTPR_HS | ulTPR;
    }
}

//*****************************************************************************
//
//! Sets the address that the I2C Master places on the bus.
//!
//! \param ulBase is the base address of the I2C Master module.
//! \param ucSlaveAddr 7-bit slave address
//! \param bReceive flag indicating the type of communication with the slave
//!
//! This function configures the address that the I2C Master places on the
//! bus when initiating a transaction.  When the \e bReceive parameter is set
//! to \b true, the address indicates that the I2C Master is initiating a
//! read from the slave; otherwise the address indicates that the I2C
//! Master is initiating a write to the slave.
//!
//! \return None.
//
//*****************************************************************************
void
I2CMasterSlaveAddrSet(unsigned long ulBase, unsigned char ucSlaveAddr,
                      tBoolean bReceive)
{
    //
    // Check the arguments.
    //
    ASSERT(I2CMasterBaseValid(ulBase));
    ASSERT(!(ucSlaveAddr & 0x80));

    //
    // Set the address of the slave with which the master will communicate.
    //
    HWREG(ulBase + I2C_O_MSA) = (ucSlaveAddr << 1) | bReceive;
}

//*****************************************************************************
//
//! Indicates whether or not the I2C bus is busy.
//!
//! \param ulBase is the base address of the I2C Master module.
//!
//! This function returns an indication of whether or not the I2C bus is busy.
//! This function can be used in a multi-master environment to determine if
//! another master is currently using the bus.
//!
//! \return Returns \b true if the I2C bus is busy; otherwise, returns
//! \b false.
//
//*****************************************************************************
tBoolean
I2CMasterBusBusy(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(I2CMasterBaseValid(ulBase));

    //
    // Return the bus busy status.
    //
    if(HWREG(ulBase + I2C_O_MCS) & I2C_MCS_BUSBSY)
    {
        return(true);
    }
    else
    {
        return(false);
    }
}

//*****************************************************************************
//
//! Clears I2C Master interrupt sources.
//!
//! \param ulBase is the base address of the I2C Master module.
//!
//! The I2C Master interrupt source is cleared, so that it no longer asserts.
//! This function must be called in the interrupt handler to keep the interrupt
//! from being triggered again immediately upon exit.
//!
//! \note Because there is a write buffer in the Cortex-M processor, it may
//! take several clock cycles before the interrupt source is actually cleared.
//! Therefore, it is recommended that the interrupt source be cleared early in
//! the interrupt handler (as opposed to the very last action) to avoid
//! returning from the interrupt handler before the interrupt source is
//! actually cleared.  Failure to do so may result in the interrupt handler
//! being immediately reentered (because the interrupt controller still sees
//! the interrupt source asserted).
//!
//! \return None.
//
//*****************************************************************************
void
I2CMasterIntClear(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(I2CMasterBaseValid(ulBase));

    //
    // Clear the I2C master interrupt source.
    //
    HWREG(ulBase + I2C_O_MICR) = I2C_MICR_IC;

    //
    // Workaround for I2C master interrupt clear errata for rev B Stellaris
    // devices.  For later devices, this write is ignored and therefore
    // harmless (other than the slight performance hit).
    //
    HWREG(ulBase + I2C_O_MMIS) = I2C_MICR_IC;
}