xref: /hal_ti-2.7.6/simplelink/source/ti/devices/cc32xx/driverlib/uart.c

/*
 *  Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com/
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *    Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 *    Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the
 *    distribution.
 *
 *    Neither the name of Texas Instruments Incorporated nor the names of
 *    its contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
//*****************************************************************************
//
//  uart.c
//
//  Driver for the UART.
//
//*****************************************************************************

//*****************************************************************************
//
//! \addtogroup UART_api
//! @{
//
//*****************************************************************************

#include "inc/hw_ints.h"
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "inc/hw_uart.h"
#include "debug.h"
#include "interrupt.h"
#include "uart.h"


//*****************************************************************************
//
// A mapping of UART base address to interupt number.
//
//*****************************************************************************
static const unsigned long g_ppulUARTIntMap[][2] =
{
    { UARTA0_BASE, INT_UARTA0 },
    { UARTA1_BASE, INT_UARTA1 },
};

//*****************************************************************************
//
//! \internal
//! Checks a UART base address.
//!
//! \param ulBase is the base address of the UART port.
//!
//! This function determines if a UART port base address is valid.
//!
//! \return Returns \b true if the base address is valid and \b false
//! otherwise.
//
//*****************************************************************************
#ifdef DEBUG
static tBoolean
UARTBaseValid(unsigned long ulBase)
{
    return((ulBase == UARTA0_BASE) || (ulBase == UARTA1_BASE));
}
#endif

//*****************************************************************************
//
//! \internal
//! Gets the UART interrupt number.
//!
//! \param ulBase is the base address of the UART port.
//!
//! Given a UART base address, returns the corresponding interrupt number.
//!
//! \return Returns a UART interrupt number, or -1 if \e ulBase is invalid.
//
//*****************************************************************************
static long
UARTIntNumberGet(unsigned long ulBase)
{
    unsigned long ulIdx;

    //
    // Loop through the table that maps UART base addresses to interrupt
    // numbers.
    //
    for(ulIdx = 0; ulIdx < (sizeof(g_ppulUARTIntMap) /
                            sizeof(g_ppulUARTIntMap[0])); ulIdx++)
    {
        //
        // See if this base address matches.
        //
        if(g_ppulUARTIntMap[ulIdx][0] == ulBase)
        {
            //
            // Return the corresponding interrupt number.
            //
            return(g_ppulUARTIntMap[ulIdx][1]);
        }
    }

    //
    // The base address could not be found, so return an error.
    //
    return(-1);
}

//*****************************************************************************
//
//! Sets the type of parity.
//!
//! \param ulBase is the base address of the UART port.
//! \param ulParity specifies the type of parity to use.
//!
//! This function sets the type of parity to use for transmitting and expect
//! when receiving.  The \e ulParity parameter must be one of
//! \b UART_CONFIG_PAR_NONE, \b UART_CONFIG_PAR_EVEN, \b UART_CONFIG_PAR_ODD,
//! \b UART_CONFIG_PAR_ONE, or \b UART_CONFIG_PAR_ZERO.  The last two allow
//! direct control of the parity bit; it is always either one or zero based on
//! the mode.
//!
//! \return None.
//
//*****************************************************************************
void
UARTParityModeSet(unsigned long ulBase, unsigned long ulParity)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));
    ASSERT((ulParity == UART_CONFIG_PAR_NONE) ||
           (ulParity == UART_CONFIG_PAR_EVEN) ||
           (ulParity == UART_CONFIG_PAR_ODD) ||
           (ulParity == UART_CONFIG_PAR_ONE) ||
           (ulParity == UART_CONFIG_PAR_ZERO));

    //
    // Set the parity mode.
    //
    HWREG(ulBase + UART_O_LCRH) = ((HWREG(ulBase + UART_O_LCRH) &
                                    ~(UART_LCRH_SPS | UART_LCRH_EPS |
                                      UART_LCRH_PEN)) | ulParity);
}

//*****************************************************************************
//
//! Gets the type of parity currently being used.
//!
//! \param ulBase is the base address of the UART port.
//!
//! This function gets the type of parity used for transmitting data and
//! expected when receiving data.
//!
//! \return Returns the current parity settings, specified as one of
//! \b UART_CONFIG_PAR_NONE, \b UART_CONFIG_PAR_EVEN, \b UART_CONFIG_PAR_ODD,
//! \b UART_CONFIG_PAR_ONE, or \b UART_CONFIG_PAR_ZERO.
//
//*****************************************************************************
unsigned long
UARTParityModeGet(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // Return the current parity setting.
    //
    return(HWREG(ulBase + UART_O_LCRH) &
           (UART_LCRH_SPS | UART_LCRH_EPS | UART_LCRH_PEN));
}

//*****************************************************************************
//
//! Sets the FIFO level at which interrupts are generated.
//!
//! \param ulBase is the base address of the UART port.
//! \param ulTxLevel is the transmit FIFO interrupt level, specified as one of
//! \b UART_FIFO_TX1_8, \b UART_FIFO_TX2_8, \b UART_FIFO_TX4_8,
//! \b UART_FIFO_TX6_8, or \b UART_FIFO_TX7_8.
//! \param ulRxLevel is the receive FIFO interrupt level, specified as one of
//! \b UART_FIFO_RX1_8, \b UART_FIFO_RX2_8, \b UART_FIFO_RX4_8,
//! \b UART_FIFO_RX6_8, or \b UART_FIFO_RX7_8.
//!
//! This function sets the FIFO level at which transmit and receive interrupts
//! are generated.
//!
//! \return None.
//
//*****************************************************************************
void
UARTFIFOLevelSet(unsigned long ulBase, unsigned long ulTxLevel,
                 unsigned long ulRxLevel)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));
    ASSERT((ulTxLevel == UART_FIFO_TX1_8) ||
           (ulTxLevel == UART_FIFO_TX2_8) ||
           (ulTxLevel == UART_FIFO_TX4_8) ||
           (ulTxLevel == UART_FIFO_TX6_8) ||
           (ulTxLevel == UART_FIFO_TX7_8));
    ASSERT((ulRxLevel == UART_FIFO_RX1_8) ||
           (ulRxLevel == UART_FIFO_RX2_8) ||
           (ulRxLevel == UART_FIFO_RX4_8) ||
           (ulRxLevel == UART_FIFO_RX6_8) ||
           (ulRxLevel == UART_FIFO_RX7_8));

    //
    // Set the FIFO interrupt levels.
    //
    HWREG(ulBase + UART_O_IFLS) = ulTxLevel | ulRxLevel;
}

//*****************************************************************************
//
//! Gets the FIFO level at which interrupts are generated.
//!
//! \param ulBase is the base address of the UART port.
//! \param pulTxLevel is a pointer to storage for the transmit FIFO level,
//! returned as one of \b UART_FIFO_TX1_8, \b UART_FIFO_TX2_8,
//! \b UART_FIFO_TX4_8, \b UART_FIFO_TX6_8, or \b UART_FIFO_TX7_8.
//! \param pulRxLevel is a pointer to storage for the receive FIFO level,
//! returned as one of \b UART_FIFO_RX1_8, \b UART_FIFO_RX2_8,
//! \b UART_FIFO_RX4_8, \b UART_FIFO_RX6_8, or \b UART_FIFO_RX7_8.
//!
//! This function gets the FIFO level at which transmit and receive interrupts
//! are generated.
//!
//! \return None.
//
//*****************************************************************************
void
UARTFIFOLevelGet(unsigned long ulBase, unsigned long *pulTxLevel,
                 unsigned long *pulRxLevel)
{
    unsigned long ulTemp;

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

    //
    // Read the FIFO level register.
    //
    ulTemp = HWREG(ulBase + UART_O_IFLS);

    //
    // Extract the transmit and receive FIFO levels.
    //
    *pulTxLevel = ulTemp & UART_IFLS_TX_M;
    *pulRxLevel = ulTemp & UART_IFLS_RX_M;
}

//*****************************************************************************
//
//! Sets the configuration of a UART.
//!
//! \param ulBase is the base address of the UART port.
//! \param ulUARTClk is the rate of the clock supplied to the UART module.
//! \param ulBaud is the desired baud rate.
//! \param ulConfig is the data format for the port (number of data bits,
//! number of stop bits, and parity).
//!
//! This function configures the UART for operation in the specified data
//! format.  The baud rate is provided in the \e ulBaud parameter and the data
//! format in the \e ulConfig parameter.
//!
//! The \e ulConfig parameter is the logical OR of three values: the number of
//! data bits, the number of stop bits, and the parity.  \b UART_CONFIG_WLEN_8,
//! \b UART_CONFIG_WLEN_7, \b UART_CONFIG_WLEN_6, and \b UART_CONFIG_WLEN_5
//! select from eight to five data bits per byte (respectively).
//! \b UART_CONFIG_STOP_ONE and \b UART_CONFIG_STOP_TWO select one or two stop
//! bits (respectively).  \b UART_CONFIG_PAR_NONE, \b UART_CONFIG_PAR_EVEN,
//! \b UART_CONFIG_PAR_ODD, \b UART_CONFIG_PAR_ONE, and \b UART_CONFIG_PAR_ZERO
//! select the parity mode (no parity bit, even parity bit, odd parity bit,
//! parity bit always one, and parity bit always zero, respectively).
//!
//! The peripheral clock frequency is returned by PRCMPeripheralClockGet().
//!
//!
//! \return None.
//
//*****************************************************************************
void
UARTConfigSetExpClk(unsigned long ulBase, unsigned long ulUARTClk,
                    unsigned long ulBaud, unsigned long ulConfig)
{
    unsigned long ulDiv;

    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));
    ASSERT(ulBaud != 0);

    //
    // Stop the UART.
    //
    UARTDisable(ulBase);

    //
    // Is the required baud rate greater than the maximum rate supported
    // without the use of high speed mode?
    //
    if((ulBaud * 16) > ulUARTClk)
    {
        //
        // Enable high speed mode.
        //
        HWREG(ulBase + UART_O_CTL) |= UART_CTL_HSE;

        //
        // Half the supplied baud rate to compensate for enabling high speed
        // mode.  This allows the following code to be common to both cases.
        //
        ulBaud /= 2;
    }
    else
    {
        //
        // Disable high speed mode.
        //
        HWREG(ulBase + UART_O_CTL) &= ~(UART_CTL_HSE);
    }

    //
    // Compute the fractional baud rate divider.
    //
    ulDiv = (((ulUARTClk * 8) / ulBaud) + 1) / 2;

    //
    // Set the baud rate.
    //
    HWREG(ulBase + UART_O_IBRD) = ulDiv / 64;
    HWREG(ulBase + UART_O_FBRD) = ulDiv % 64;

    //
    // Set parity, data length, and number of stop bits.
    //
    HWREG(ulBase + UART_O_LCRH) = ulConfig;

    //
    // Clear the flags register.
    //
    HWREG(ulBase + UART_O_FR) = 0;

    //
    // Start the UART.
    //
    UARTEnable(ulBase);
}

//*****************************************************************************
//
//! Gets the current configuration of a UART.
//!
//! \param ulBase is the base address of the UART port.
//! \param ulUARTClk is the rate of the clock supplied to the UART module.
//! \param pulBaud is a pointer to storage for the baud rate.
//! \param pulConfig is a pointer to storage for the data format.
//!
//! The baud rate and data format for the UART is determined, given an
//! explicitly provided peripheral clock (hence the ExpClk suffix).  The
//! returned baud rate is the actual baud rate; it may not be the exact baud
//! rate requested or an ``official'' baud rate.  The data format returned in
//! \e pulConfig is enumerated the same as the \e ulConfig parameter of
//! UARTConfigSetExpClk().
//!
//! The peripheral clock frequency is returned by PRCMPeripheralClockGet().
//!
//!
//! \return None.
//
//*****************************************************************************
void
UARTConfigGetExpClk(unsigned long ulBase, unsigned long ulUARTClk,
                    unsigned long *pulBaud, unsigned long *pulConfig)
{
    unsigned long ulInt, ulFrac;

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

    //
    // Compute the baud rate.
    //
    ulInt = HWREG(ulBase + UART_O_IBRD);
    ulFrac = HWREG(ulBase + UART_O_FBRD);
    *pulBaud = (ulUARTClk * 4) / ((64 * ulInt) + ulFrac);

    //
    // See if high speed mode enabled.
    //
    if(HWREG(ulBase + UART_O_CTL) & UART_CTL_HSE)
    {
        //
        // High speed mode is enabled so the actual baud rate is actually
        // double what was just calculated.
        //
        *pulBaud *= 2;
    }

    //
    // Get the parity, data length, and number of stop bits.
    //
    *pulConfig = (HWREG(ulBase + UART_O_LCRH) &
                  (UART_LCRH_SPS | UART_LCRH_WLEN_M | UART_LCRH_STP2 |
                   UART_LCRH_EPS | UART_LCRH_PEN));
}

//*****************************************************************************
//
//! Enables transmitting and receiving.
//!
//! \param ulBase is the base address of the UART port.
//!
//! This function sets the UARTEN, TXE, and RXE bits, and enables the transmit
//! and receive FIFOs.
//!
//! \return None.
//
//*****************************************************************************
void
UARTEnable(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // Enable the FIFO.
    //
    HWREG(ulBase + UART_O_LCRH) |= UART_LCRH_FEN;

    //
    // Enable RX, TX, and the UART.
    //
    HWREG(ulBase + UART_O_CTL) |= (UART_CTL_UARTEN | UART_CTL_TXE |
                                   UART_CTL_RXE);
}

//*****************************************************************************
//
//! Disables transmitting and receiving.
//!
//! \param ulBase is the base address of the UART port.
//!
//! This function clears the UARTEN, TXE, and RXE bits, waits for the end of
//! transmission of the current character, and flushes the transmit FIFO.
//!
//! \return None.
//
//*****************************************************************************
void
UARTDisable(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // Wait for end of TX.
    //
    while(HWREG(ulBase + UART_O_FR) & UART_FR_BUSY)
    {
    }

    //
    // Disable the FIFO.
    //
    HWREG(ulBase + UART_O_LCRH) &= ~(UART_LCRH_FEN);

    //
    // Disable the UART.
    //
    HWREG(ulBase + UART_O_CTL) &= ~(UART_CTL_UARTEN | UART_CTL_TXE |
                                    UART_CTL_RXE);
}

//*****************************************************************************
//
//! Enables the transmit and receive FIFOs.
//!
//! \param ulBase is the base address of the UART port.
//!
//! This functions enables the transmit and receive FIFOs in the UART.
//!
//! \return None.
//
//*****************************************************************************
void
UARTFIFOEnable(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // Enable the FIFO.
    //
    HWREG(ulBase + UART_O_LCRH) |= UART_LCRH_FEN;
}

//*****************************************************************************
//
//! Disables the transmit and receive FIFOs.
//!
//! \param ulBase is the base address of the UART port.
//!
//! This functions disables the transmit and receive FIFOs in the UART.
//!
//! \return None.
//
//*****************************************************************************
void
UARTFIFODisable(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // Disable the FIFO.
    //
    HWREG(ulBase + UART_O_LCRH) &= ~(UART_LCRH_FEN);
}

//*****************************************************************************
//
//! Sets the states of the RTS modem control signals.
//!
//! \param ulBase is the base address of the UART port.
//! \param ulControl is a bit-mapped flag indicating which modem control bits
//! should be set.
//!
//! This function sets the states of the RTS modem handshake outputs
//! from the UART.
//!
//! The \e ulControl parameter is the logical OR of any of the following:
//!
//! - \b UART_OUTPUT_RTS - The Modem Control RTS signal
//!
//! \note The availability of hardware modem handshake signals varies with the
//!  part and UART in use.  Please consult the datasheet for the part
//! you are using to determine whether this support is available.
//!
//! \return None.
//
//*****************************************************************************
void
UARTModemControlSet(unsigned long ulBase, unsigned long ulControl)
{
    unsigned long ulTemp;

    //
    // Check the arguments.
    //

    ASSERT(ulBase == UARTA1_BASE);
    ASSERT((ulControl & ~(UART_OUTPUT_RTS)) == 0);

    //
    // Set the appropriate modem control output bits.
    //
    ulTemp = HWREG(ulBase + UART_O_CTL);
    ulTemp |= (ulControl & (UART_OUTPUT_RTS));
    HWREG(ulBase + UART_O_CTL) = ulTemp;
}

//*****************************************************************************
//
//! Clears the states of the RTS modem control signals.
//!
//! \param ulBase is the base address of the UART port.
//! \param ulControl is a bit-mapped flag indicating which modem control bits
//! should be set.
//!
//! This function clears the states of the RTS modem handshake outputs
//! from the UART.
//!
//! The \e ulControl parameter is the logical OR of any of the following:
//!
//! - \b UART_OUTPUT_RTS - The Modem Control RTS signal
//!
//! \note The availability of hardware modem handshake signals varies with the
//!  part and UART in use.  Please consult the datasheet for the part
//! you are using to determine whether this support is available.
//!
//! \return None.
//
//*****************************************************************************
void
UARTModemControlClear(unsigned long ulBase, unsigned long ulControl)
{
    unsigned long ulTemp;

    //
    // Check the arguments.
    //
    ASSERT(ulBase == UARTA1_BASE);
    ASSERT((ulControl & ~(UART_OUTPUT_RTS)) == 0);

    //
    // Set the appropriate modem control output bits.
    //
    ulTemp = HWREG(ulBase + UART_O_CTL);
    ulTemp &= ~(ulControl & (UART_OUTPUT_RTS));
    HWREG(ulBase + UART_O_CTL) = ulTemp;
}

//*****************************************************************************
//
//! Gets the states of the RTS modem control signals.
//!
//! \param ulBase is the base address of the UART port.
//!
//! This function returns the current states of each of the UART modem
//! control signal, RTS.
//!
//! \note The availability of hardware modem handshake signals varies with the
//!  part and UART in use.  Please consult the datasheet for the part
//! you are using to determine whether this support is available.
//!
//! \return Returns the states of the handshake output signal.
//
//*****************************************************************************
unsigned long
UARTModemControlGet(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(ulBase == UARTA1_BASE);

    return(HWREG(ulBase + UART_O_CTL) & (UART_OUTPUT_RTS));
}

//*****************************************************************************
//
//! Gets the states of the CTS modem status signal.
//!
//! \param ulBase is the base address of the UART port.
//!
//! This function returns the current states of the UART modem status signal,
//! CTS.
//!
//! \note The availability of hardware modem handshake signals varies with the
//!  part and UART in use.  Please consult the datasheet for the part
//! you are using to determine whether this support is available.
//!
//! \return Returns the states of the handshake output signal
//
//*****************************************************************************
unsigned long
UARTModemStatusGet(unsigned long ulBase)
{
    //
    // Check the arguments.
    //

    ASSERT(ulBase == UARTA1_BASE);

    return(HWREG(ulBase + UART_O_FR) & (UART_INPUT_CTS));
}

//*****************************************************************************
//
//! Sets the UART hardware flow control mode to be used.
//!
//! \param ulBase is the base address of the UART port.
//! \param ulMode indicates the flow control modes to be used.  This parameter
//! is a logical OR combination of values \b UART_FLOWCONTROL_TX and
//! \b UART_FLOWCONTROL_RX to enable hardware transmit (CTS) and receive (RTS)
//! flow control or \b UART_FLOWCONTROL_NONE to disable hardware flow control.
//!
//! This function sets the required hardware flow control modes.  If \e ulMode
//! contains flag \b UART_FLOWCONTROL_TX, data is only transmitted if the
//! incoming CTS signal is asserted. If \e ulMode contains flag
//! \b UART_FLOWCONTROL_RX, the RTS output is controlled by the hardware and is
//! asserted only when there is space available in the receive FIFO.  If no
//! hardware flow control is required, \b UART_FLOWCONTROL_NONE should be
//! passed.
//!
//! \note The availability of hardware flow control varies with the
//! part and UART in use.  Please consult the datasheet for the part you are
//! using to determine whether this support is available.
//!
//! \return None.
//
//*****************************************************************************
void
UARTFlowControlSet(unsigned long ulBase, unsigned long ulMode)
{
    //
    // Check the arguments.
    //

    ASSERT(UARTBaseValid(ulBase));
    ASSERT((ulMode & ~(UART_FLOWCONTROL_TX | UART_FLOWCONTROL_RX)) == 0);

    //
    // Set the flow control mode as requested.
    //
    HWREG(ulBase + UART_O_CTL) = ((HWREG(ulBase + UART_O_CTL) &
                                 ~(UART_FLOWCONTROL_TX |
                                   UART_FLOWCONTROL_RX)) | ulMode);
}

//*****************************************************************************
//
//! Returns the UART hardware flow control mode currently in use.
//!
//! \param ulBase is the base address of the UART port.
//!
//! This function returns the current hardware flow control mode.
//!
//! \note The availability of hardware flow control varies with the
//! part and UART in use.  Please consult the datasheet for the part you are
//! using to determine whether this support is available.
//!
//! \return Returns the current flow control mode in use.  This is a
//! logical OR combination of values \b UART_FLOWCONTROL_TX if transmit
//! (CTS) flow control is enabled and \b UART_FLOWCONTROL_RX if receive (RTS)
//! flow control is in use.  If hardware flow control is disabled,
//! \b UART_FLOWCONTROL_NONE is returned.
//
//*****************************************************************************
unsigned long
UARTFlowControlGet(unsigned long ulBase)
{
    //
    // Check the arguments.
    //

    ASSERT(UARTBaseValid(ulBase));

    return(HWREG(ulBase + UART_O_CTL) & (UART_FLOWCONTROL_TX |
                                         UART_FLOWCONTROL_RX));
}

//*****************************************************************************
//
//! Sets the operating mode for the UART transmit interrupt.
//!
//! \param ulBase is the base address of the UART port.
//! \param ulMode is the operating mode for the transmit interrupt.  It may be
//! \b UART_TXINT_MODE_EOT to trigger interrupts when the transmitter is idle
//! or \b UART_TXINT_MODE_FIFO to trigger based on the current transmit FIFO
//! level.
//!
//! This function allows the mode of the UART transmit interrupt to be set.  By
//! default, the transmit interrupt is asserted when the FIFO level falls past
//! a threshold set via a call to UARTFIFOLevelSet().  Alternatively, if this
//! function is called with \e ulMode set to \b UART_TXINT_MODE_EOT, the
//! transmit interrupt is asserted once the transmitter is completely idle -
//! the transmit FIFO is empty and all bits, including any stop bits, have
//! cleared the transmitter.
//!
//! \note The availability of end-of-transmission mode varies with the
//!  part in use.  Please consult the datasheet for the part you are
//! using to determine whether this support is available.
//!
//! \return None.
//
//*****************************************************************************
void
UARTTxIntModeSet(unsigned long ulBase, unsigned long ulMode)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));
    ASSERT((ulMode == UART_TXINT_MODE_EOT) ||
           (ulMode == UART_TXINT_MODE_FIFO));

    //
    // Set or clear the EOT bit of the UART control register as appropriate.
    //
    HWREG(ulBase + UART_O_CTL) = ((HWREG(ulBase + UART_O_CTL) &
                                 ~(UART_TXINT_MODE_EOT |
                                   UART_TXINT_MODE_FIFO)) | ulMode);
}

//*****************************************************************************
//
//! Returns the current operating mode for the UART transmit interrupt.
//!
//! \param ulBase is the base address of the UART port.
//!
//! This function returns the current operating mode for the UART transmit
//! interrupt.  The return value is \b UART_TXINT_MODE_EOT if the transmit
//! interrupt is currently set to be asserted once the transmitter is
//! completely idle - the transmit FIFO is empty and all bits, including any
//! stop bits, have cleared the transmitter.  The return value is
//! \b UART_TXINT_MODE_FIFO if the interrupt is set to be asserted based upon
//! the level of the transmit FIFO.
//!
//! \note The availability of end-of-transmission mode varies with the
//!  part in use.  Please consult the datasheet for the part you are
//! using to determine whether this support is available.
//!
//! \return Returns \b UART_TXINT_MODE_FIFO or \b UART_TXINT_MODE_EOT.
//
//*****************************************************************************
unsigned long
UARTTxIntModeGet(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // Return the current transmit interrupt mode.
    //
    return(HWREG(ulBase + UART_O_CTL) & (UART_TXINT_MODE_EOT |
                                         UART_TXINT_MODE_FIFO));
}

//*****************************************************************************
//
//! Determines if there are any characters in the receive FIFO.
//!
//! \param ulBase is the base address of the UART port.
//!
//! This function returns a flag indicating whether or not there is data
//! available in the receive FIFO.
//!
//! \return Returns \b true if there is data in the receive FIFO or \b false
//! if there is no data in the receive FIFO.
//
//*****************************************************************************
tBoolean
UARTCharsAvail(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // Return the availability of characters.
    //
    return((HWREG(ulBase + UART_O_FR) & UART_FR_RXFE) ? false : true);
}

//*****************************************************************************
//
//! Determines if there is any space in the transmit FIFO.
//!
//! \param ulBase is the base address of the UART port.
//!
//! This function returns a flag indicating whether or not there is space
//! available in the transmit FIFO.
//!
//! \return Returns \b true if there is space available in the transmit FIFO
//! or \b false if there is no space available in the transmit FIFO.
//
//*****************************************************************************
tBoolean
UARTSpaceAvail(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // Return the availability of space.
    //
    return((HWREG(ulBase + UART_O_FR) & UART_FR_TXFF) ? false : true);
}

//*****************************************************************************
//
//! Receives a character from the specified port.
//!
//! \param ulBase is the base address of the UART port.
//!
//! This function gets a character from the receive FIFO for the specified
//! port.
//!
//!
//! \return Returns the character read from the specified port, cast as a
//! \e long.  A \b -1 is returned if there are no characters present in the
//! receive FIFO.  The UARTCharsAvail() function should be called before
//! attempting to call this function.
//
//*****************************************************************************
long
UARTCharGetNonBlocking(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // See if there are any characters in the receive FIFO.
    //
    if(!(HWREG(ulBase + UART_O_FR) & UART_FR_RXFE))
    {
        //
        // Read and return the next character.
        //
        return(HWREG(ulBase + UART_O_DR));
    }
    else
    {
        //
        // There are no characters, so return a failure.
        //
        return(-1);
    }
}

//*****************************************************************************
//
//! Waits for a character from the specified port.
//!
//! \param ulBase is the base address of the UART port.
//!
//! This function gets a character from the receive FIFO for the specified
//! port.  If there are no characters available, this function waits until a
//! character is received before returning.
//!
//! \return Returns the character read from the specified port, cast as a
//! \e long.
//
//*****************************************************************************
long
UARTCharGet(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // Wait until a char is available.
    //
    while(HWREG(ulBase + UART_O_FR) & UART_FR_RXFE)
    {
    }

    //
    // Now get the char.
    //
    return(HWREG(ulBase + UART_O_DR));
}

//*****************************************************************************
//
//! Sends a character to the specified port.
//!
//! \param ulBase is the base address of the UART port.
//! \param ucData is the character to be transmitted.
//!
//! This function writes the character \e ucData to the transmit FIFO for the
//! specified port.  This function does not block, so if there is no space
//! available, then a \b false is returned, and the application must retry the
//! function later.
//!
//! \return Returns \b true if the character was successfully placed in the
//! transmit FIFO or \b false if there was no space available in the transmit
//! FIFO.
//
//*****************************************************************************
tBoolean
UARTCharPutNonBlocking(unsigned long ulBase, unsigned char ucData)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // See if there is space in the transmit FIFO.
    //
    if(!(HWREG(ulBase + UART_O_FR) & UART_FR_TXFF))
    {
        //
        // Write this character to the transmit FIFO.
        //
        HWREG(ulBase + UART_O_DR) = ucData;

        //
        // Success.
        //
        return(true);
    }
    else
    {
        //
        // There is no space in the transmit FIFO, so return a failure.
        //
        return(false);
    }
}

//*****************************************************************************
//
//! Waits to send a character from the specified port.
//!
//! \param ulBase is the base address of the UART port.
//! \param ucData is the character to be transmitted.
//!
//! This function sends the character \e ucData to the transmit FIFO for the
//! specified port.  If there is no space available in the transmit FIFO, this
//! function waits until there is space available before returning.
//!
//! \return None.
//
//*****************************************************************************
void
UARTCharPut(unsigned long ulBase, unsigned char ucData)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // Wait until space is available.
    //
    while(HWREG(ulBase + UART_O_FR) & UART_FR_TXFF)
    {
    }

    //
    // Send the char.
    //
    HWREG(ulBase + UART_O_DR) = ucData;
}

//*****************************************************************************
//
//! Causes a BREAK to be sent.
//!
//! \param ulBase is the base address of the UART port.
//! \param bBreakState controls the output level.
//!
//! Calling this function with \e bBreakState set to \b true asserts a break
//! condition on the UART.  Calling this function with \e bBreakState set to
//! \b false removes the break condition.  For proper transmission of a break
//! command, the break must be asserted for at least two complete frames.
//!
//! \return None.
//
//*****************************************************************************
void
UARTBreakCtl(unsigned long ulBase, tBoolean bBreakState)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // Set the break condition as requested.
    //
    HWREG(ulBase + UART_O_LCRH) =
        (bBreakState ?
         (HWREG(ulBase + UART_O_LCRH) | UART_LCRH_BRK) :
         (HWREG(ulBase + UART_O_LCRH) & ~(UART_LCRH_BRK)));
}

//*****************************************************************************
//
//! Determines whether the UART transmitter is busy or not.
//!
//! \param ulBase is the base address of the UART port.
//!
//! Allows the caller to determine whether all transmitted bytes have cleared
//! the transmitter hardware.  If \b false is returned, the transmit FIFO is
//! empty and all bits of the last transmitted character, including all stop
//! bits, have left the hardware shift register.
//!
//! \return Returns \b true if the UART is transmitting or \b false if all
//! transmissions are complete.
//
//*****************************************************************************
tBoolean
UARTBusy(unsigned long ulBase)
{
    //
    // Check the argument.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // Determine if the UART is busy.
    //
    return((HWREG(ulBase + UART_O_FR) & UART_FR_BUSY) ? true : false);
}

//*****************************************************************************
//
//! Registers an interrupt handler for a UART interrupt.
//!
//! \param ulBase is the base address of the UART port.
//! \param pfnHandler is a pointer to the function to be called when the
//! UART interrupt occurs.
//!
//! This function does the actual registering of the interrupt handler.  This
//! function enables the global interrupt in the interrupt controller; specific
//! UART interrupts must be enabled via UARTIntEnable().  It is the interrupt
//! handler's responsibility to clear the interrupt source.
//!
//! \sa IntRegister() for important information about registering interrupt
//! handlers.
//!
//! \return None.
//
//*****************************************************************************
void
UARTIntRegister(unsigned long ulBase, void (*pfnHandler)(void))
{
    unsigned long ulInt;

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

    //
    // Determine the interrupt number based on the UART port.
    //

    ulInt = UARTIntNumberGet(ulBase);

    //
    // Register the interrupt handler.
    //
    IntRegister(ulInt, pfnHandler);

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

//*****************************************************************************
//
//! Unregisters an interrupt handler for a UART interrupt.
//!
//! \param ulBase is the base address of the UART port.
//!
//! This function does the actual unregistering of the interrupt handler.  It
//! clears the handler to be called when a UART interrupt occurs.  This
//! function also masks off the interrupt in the interrupt controller so that
//! the interrupt handler no longer is called.
//!
//! \sa IntRegister() for important information about registering interrupt
//! handlers.
//!
//! \return None.
//
//*****************************************************************************
void
UARTIntUnregister(unsigned long ulBase)
{
    unsigned long ulInt;

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

    //
    // Determine the interrupt number based on the UART port.
    //
    ulInt = UARTIntNumberGet(ulBase);

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

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

//*****************************************************************************
//
//! Enables individual UART interrupt sources.
//!
//! \param ulBase is the base address of the UART port.
//! \param ulIntFlags is the bit mask of the interrupt sources to be enabled.
//!
//! This function enables the indicated UART 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 is the logical OR of any of the following:
//!
//! - \b UART_INT_OE - Overrun Error interrupt
//! - \b UART_INT_BE - Break Error interrupt
//! - \b UART_INT_PE - Parity Error interrupt
//! - \b UART_INT_FE - Framing Error interrupt
//! - \b UART_INT_RT - Receive Timeout interrupt
//! - \b UART_INT_TX - Transmit interrupt
//! - \b UART_INT_RX - Receive interrupt
//! - \b UART_INT_CTS - CTS interrupt
//!
//! \return None.
//
//*****************************************************************************
void
UARTIntEnable(unsigned long ulBase, unsigned long ulIntFlags)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // Enable the specified interrupts.
    //
    HWREG(ulBase + UART_O_IM) |= ulIntFlags;
}

//*****************************************************************************
//
//! Disables individual UART interrupt sources.
//!
//! \param ulBase is the base address of the UART port.
//! \param ulIntFlags is the bit mask of the interrupt sources to be disabled.
//!
//! This function disables the indicated UART 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 UARTIntEnable().
//!
//! \return None.
//
//*****************************************************************************
void
UARTIntDisable(unsigned long ulBase, unsigned long ulIntFlags)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // Disable the specified interrupts.
    //
    HWREG(ulBase + UART_O_IM) &= ~(ulIntFlags);
}

//*****************************************************************************
//
//! Gets the current interrupt status.
//!
//! \param ulBase is the base address of the UART port.
//! \param bMasked is \b false if the raw interrupt status is required and
//! \b true if the masked interrupt status is required.
//!
//! This function returns the interrupt status for the specified UART.  Either
//! the raw interrupt status or the status of interrupts that are allowed to
//! reflect to the processor can be returned.
//!
//! \return Returns the current interrupt status, enumerated as a bit field of
//! values described in UARTIntEnable().
//
//*****************************************************************************
unsigned long
UARTIntStatus(unsigned long ulBase, tBoolean bMasked)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // Return either the interrupt status or the raw interrupt status as
    // requested.
    //
    if(bMasked)
    {
        return(HWREG(ulBase + UART_O_MIS));
    }
    else
    {
        return(HWREG(ulBase + UART_O_RIS));
    }
}

//*****************************************************************************
//
//! Clears UART interrupt sources.
//!
//! \param ulBase is the base address of the UART port.
//! \param ulIntFlags is a bit mask of the interrupt sources to be cleared.
//!
//! The specified UART 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 recognized again immediately upon exit.
//!
//! The \e ulIntFlags parameter has the same definition as the \e ulIntFlags
//! parameter to UARTIntEnable().
//!
//! \note Because there is a write buffer in the Cortex-M3 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
UARTIntClear(unsigned long ulBase, unsigned long ulIntFlags)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // Clear the requested interrupt sources.
    //
    HWREG(ulBase + UART_O_ICR) = ulIntFlags;
}

//*****************************************************************************
//
//! Enable UART DMA operation.
//!
//! \param ulBase is the base address of the UART port.
//! \param ulDMAFlags is a bit mask of the DMA features to enable.
//!
//! The specified UART DMA features are enabled.  The UART can be
//! configured to use DMA for transmit or receive, and to disable
//! receive if an error occurs.  The \e ulDMAFlags parameter is the
//! logical OR of any of the following values:
//!
//! - UART_DMA_RX - enable DMA for receive
//! - UART_DMA_TX - enable DMA for transmit
//! - UART_DMA_ERR_RXSTOP - disable DMA receive on UART error
//!
//! \note The uDMA controller must also be set up before DMA can be used
//! with the UART.
//!
//! \return None.
//
//*****************************************************************************
void
UARTDMAEnable(unsigned long ulBase, unsigned long ulDMAFlags)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // Set the requested bits in the UART DMA control register.
    //
    HWREG(ulBase + UART_O_DMACTL) |= ulDMAFlags;
}

//*****************************************************************************
//
//! Disable UART DMA operation.
//!
//! \param ulBase is the base address of the UART port.
//! \param ulDMAFlags is a bit mask of the DMA features to disable.
//!
//! This function is used to disable UART DMA features that were enabled
//! by UARTDMAEnable().  The specified UART DMA features are disabled.  The
//! \e ulDMAFlags parameter is the logical OR of any of the following values:
//!
//! - UART_DMA_RX - disable DMA for receive
//! - UART_DMA_TX - disable DMA for transmit
//! - UART_DMA_ERR_RXSTOP - do not disable DMA receive on UART error
//!
//! \return None.
//
//*****************************************************************************
void
UARTDMADisable(unsigned long ulBase, unsigned long ulDMAFlags)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // Clear the requested bits in the UART DMA control register.
    //
    HWREG(ulBase + UART_O_DMACTL) &= ~ulDMAFlags;
}

//*****************************************************************************
//
//! Gets current receiver errors.
//!
//! \param ulBase is the base address of the UART port.
//!
//! This function returns the current state of each of the 4 receiver error
//! sources.  The returned errors are equivalent to the four error bits
//! returned via the previous call to UARTCharGet() or UARTCharGetNonBlocking()
//! with the exception that the overrun error is set immediately the overrun
//! occurs rather than when a character is next read.
//!
//! \return Returns a logical OR combination of the receiver error flags,
//! \b UART_RXERROR_FRAMING, \b UART_RXERROR_PARITY, \b UART_RXERROR_BREAK
//! and \b UART_RXERROR_OVERRUN.
//
//*****************************************************************************
unsigned long
UARTRxErrorGet(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // Return the current value of the receive status register.
    //
    return(HWREG(ulBase + UART_O_RSR) & 0x0000000F);
}

//*****************************************************************************
//
//! Clears all reported receiver errors.
//!
//! \param ulBase is the base address of the UART port.
//!
//! This function is used to clear all receiver error conditions reported via
//! UARTRxErrorGet().  If using the overrun, framing error, parity error or
//! break interrupts, this function must be called after clearing the interrupt
//! to ensure that later errors of the same type trigger another interrupt.
//!
//! \return None.
//
//*****************************************************************************
void
UARTRxErrorClear(unsigned long ulBase)
{
    //
    // Check the arguments.
    //
    ASSERT(UARTBaseValid(ulBase));

    //
    // Any write to the Error Clear Register will clear all bits which are
    // currently set.
    //
    HWREG(ulBase + UART_O_ECR) = 0;
}

//*****************************************************************************
//
// Close the Doxygen group.
//! @}
//
//*****************************************************************************