firmware/atmel_softpack_libraries/libchip_sam3s/source/twid.c

/* ----------------------------------------------------------------------------
 *         ATMEL Microcontroller Software Support
 * ----------------------------------------------------------------------------
 * Copyright (c) 2009, Atmel Corporation
 *
 * All rights reserved.
 *
 * 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 disclaimer below.
 *
 * Atmel's name may not be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
 * DISCLAIMED. IN NO EVENT SHALL ATMEL 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.
 * ----------------------------------------------------------------------------
 */


/*----------------------------------------------------------------------------
 *        Headers
 *----------------------------------------------------------------------------*/
#include "chip.h"

#include <assert.h>

/*----------------------------------------------------------------------------
 *        Definition
 *----------------------------------------------------------------------------*/
#define TWITIMEOUTMAX 50000

/*----------------------------------------------------------------------------
 *        Types
 *----------------------------------------------------------------------------*/

/** TWI driver callback function.*/
typedef void (*TwiCallback)(Async *);

/** \brief TWI asynchronous transfer descriptor.*/
typedef struct _AsyncTwi {

    /** Asynchronous transfer status. */
    volatile uint8_t status;
    // Callback function to invoke when transfer completes or fails.*/
    TwiCallback callback;
    /** Pointer to the data buffer.*/
    uint8_t *pData;
    /** Total number of bytes to transfer.*/
    uint32_t num;
    /** Number of already transferred bytes.*/
    uint32_t transferred;

} AsyncTwi;

/*----------------------------------------------------------------------------
 *        Global functions
 *----------------------------------------------------------------------------*/
/**
 * \brief Initializes a TWI driver instance, using the given TWI peripheral.
 * \note The peripheral must have been initialized properly before calling this function.
 * \param pTwid  Pointer to the Twid instance to initialize.
 * \param pTwi  Pointer to the TWI peripheral to use.
 */
void TWID_Initialize(Twid *pTwid, Twi *pTwi)
{
    TRACE_DEBUG( "TWID_Initialize()\n\r" ) ;
    assert( pTwid != NULL ) ;
    assert( pTwi != NULL ) ;

    /* Initialize driver. */
    pTwid->pTwi = pTwi;
    pTwid->pTransfer = 0;
}


/**
 * \brief Interrupt handler for a TWI peripheral. Manages asynchronous transfer
 * occuring on the bus. This function MUST be called by the interrupt service
 * routine of the TWI peripheral if asynchronous read/write are needed.
  * \param pTwid  Pointer to a Twid instance.
 */
void TWID_Handler( Twid *pTwid )
{
    uint8_t status;
    AsyncTwi *pTransfer ;
    Twi *pTwi ;

    assert( pTwid != NULL ) ;

    pTransfer = (AsyncTwi*)pTwid->pTransfer ;
    assert( pTransfer != NULL ) ;
    pTwi = pTwid->pTwi ;
    assert( pTwi != NULL ) ;

    /* Retrieve interrupt status */
    status = TWI_GetMaskedStatus(pTwi);

    /* Byte received */
    if (TWI_STATUS_RXRDY(status)) {

        pTransfer->pData[pTransfer->transferred] = TWI_ReadByte(pTwi);
        pTransfer->transferred++;

        /* check for transfer finish */
        if (pTransfer->transferred == pTransfer->num) {

            TWI_DisableIt(pTwi, TWI_IDR_RXRDY);
            TWI_EnableIt(pTwi, TWI_IER_TXCOMP);
        }
        /* Last byte? */
        else if (pTransfer->transferred == (pTransfer->num - 1)) {

            TWI_Stop(pTwi);
        }
    }
    /* Byte sent*/
    else if (TWI_STATUS_TXRDY(status)) {

        /* Transfer finished ? */
        if (pTransfer->transferred == pTransfer->num) {

            TWI_DisableIt(pTwi, TWI_IDR_TXRDY);
            TWI_EnableIt(pTwi, TWI_IER_TXCOMP);
            TWI_SendSTOPCondition(pTwi);
        }
        /* Bytes remaining */
        else {

            TWI_WriteByte(pTwi, pTransfer->pData[pTransfer->transferred]);
            pTransfer->transferred++;
        }
    }
    /* Transfer complete*/
    else if (TWI_STATUS_TXCOMP(status)) {

        TWI_DisableIt(pTwi, TWI_IDR_TXCOMP);
        pTransfer->status = 0;
        if (pTransfer->callback) {

            pTransfer->callback((Async *) pTransfer);
        }
        pTwid->pTransfer = 0;
    }
}

/**
 * \brief Asynchronously reads data from a slave on the TWI bus. An optional
 * callback function is triggered when the transfer is complete.
 * \param pTwid  Pointer to a Twid instance.
 * \param address  TWI slave address.
 * \param iaddress  Optional slave internal address.
 * \param isize  Internal address size in bytes.
 * \param pData  Data buffer for storing received bytes.
 * \param num  Number of bytes to read.
 * \param pAsync  Asynchronous transfer descriptor.
 * \return 0 if the transfer has been started; otherwise returns a TWI error code.
 */
uint8_t TWID_Read(
    Twid *pTwid,
    uint8_t address,
    uint32_t iaddress,
    uint8_t isize,
    uint8_t *pData,
    uint32_t num,
    Async *pAsync)
{
    Twi *pTwi;
    AsyncTwi *pTransfer;
    uint32_t timeout;

    assert( pTwid != NULL ) ;
    pTwi = pTwid->pTwi;
    pTransfer = (AsyncTwi *) pTwid->pTransfer;

    assert( (address & 0x80) == 0 ) ;
    assert( (iaddress & 0xFF000000) == 0 ) ;
    assert( isize < 4 ) ;

    /* Check that no transfer is already pending*/
    if (pTransfer) {

        TRACE_ERROR("TWID_Read: A transfer is already pending\n\r");
        return TWID_ERROR_BUSY;
    }

    /* Set STOP signal if only one byte is sent*/
    if (num == 1) {

        TWI_Stop(pTwi);
    }

    /* Asynchronous transfer*/
    if (pAsync) {

        /* Update the transfer descriptor */
        pTwid->pTransfer = pAsync;
        pTransfer = (AsyncTwi *) pAsync;
        pTransfer->status = ASYNC_STATUS_PENDING;
        pTransfer->pData = pData;
        pTransfer->num = num;
        pTransfer->transferred = 0;

        /* Enable read interrupt and start the transfer */
        TWI_EnableIt(pTwi, TWI_IER_RXRDY);
        TWI_StartRead(pTwi, address, iaddress, isize);
    }
    /* Synchronous transfer*/
    else {

        /* Start read*/
        TWI_StartRead(pTwi, address, iaddress, isize);

        /* Read all bytes, setting STOP before the last byte*/
        while (num > 0) {

            /* Last byte ?*/
            if (num == 1) {

                TWI_Stop(pTwi);
            }

            /* Wait for byte then read and store it*/
            timeout = 0;
            while( !TWI_ByteReceived(pTwi) && (++timeout<TWITIMEOUTMAX) );
            if (timeout == TWITIMEOUTMAX) {
                TRACE_ERROR("TWID Timeout BR\n\r");
            }
            *pData++ = TWI_ReadByte(pTwi);
            num--;
        }

        /* Wait for transfer to be complete */
        timeout = 0;
        while( !TWI_TransferComplete(pTwi) && (++timeout<TWITIMEOUTMAX) );
        if (timeout == TWITIMEOUTMAX) {
            TRACE_ERROR("TWID Timeout TC\n\r");
        }
    }

    return 0;
}

/**
 * \brief Asynchronously sends data to a slave on the TWI bus. An optional callback
 * function is invoked whenever the transfer is complete.
 * \param pTwid  Pointer to a Twid instance.
 * \param address  TWI slave address.
 * \param iaddress  Optional slave internal address.
 * \param isize  Number of internal address bytes.
 * \param pData  Data buffer for storing received bytes.
 * \param num  Data buffer to send.
 * \param pAsync  Asynchronous transfer descriptor.
 * \return 0 if the transfer has been started; otherwise returns a TWI error code.
 */
uint8_t TWID_Write(
    Twid *pTwid,
    uint8_t address,
    uint32_t iaddress,
    uint8_t isize,
    uint8_t *pData,
    uint32_t num,
    Async *pAsync)
{
    Twi *pTwi = pTwid->pTwi;
    AsyncTwi *pTransfer = (AsyncTwi *) pTwid->pTransfer;
    uint32_t timeout;

    assert( pTwi != NULL ) ;
    assert( (address & 0x80) == 0 ) ;
    assert( (iaddress & 0xFF000000) == 0 ) ;
    assert( isize < 4 ) ;

    /* Check that no transfer is already pending */
    if (pTransfer) {

        TRACE_ERROR("TWI_Write: A transfer is already pending\n\r");
        return TWID_ERROR_BUSY;
    }

    /* Asynchronous transfer */
    if (pAsync) {

        /* Update the transfer descriptor */
        pTwid->pTransfer = pAsync;
        pTransfer = (AsyncTwi *) pAsync;
        pTransfer->status = ASYNC_STATUS_PENDING;
        pTransfer->pData = pData;
        pTransfer->num = num;
        pTransfer->transferred = 1;

        /* Enable write interrupt and start the transfer */
        TWI_StartWrite(pTwi, address, iaddress, isize, *pData);
        TWI_EnableIt(pTwi, TWI_IER_TXRDY);
    }
    /* Synchronous transfer*/
    else {

        // Start write
        TWI_StartWrite(pTwi, address, iaddress, isize, *pData++);
        num--;

        /* Send all bytes */
        while (num > 0) {

            /* Wait before sending the next byte */
            timeout = 0;
            while( !TWI_ByteSent(pTwi) && (++timeout<TWITIMEOUTMAX) );
            if (timeout == TWITIMEOUTMAX) {
                TRACE_ERROR("TWID Timeout BS\n\r");
            }

            TWI_WriteByte(pTwi, *pData++);
            num--;
        }

        /* Wait for actual end of transfer */
        timeout = 0;

        /* Send a STOP condition */
        TWI_SendSTOPCondition(pTwi);

        while( !TWI_TransferComplete(pTwi) && (++timeout<TWITIMEOUTMAX) );
        if (timeout == TWITIMEOUTMAX) {
            TRACE_ERROR("TWID Timeout TC2\n\r");
        }

    }

    return 0;
}