/* This file has been prepared for Doxygen automatic documentation generation.*/
/*! \file *********************************************************************
*
* \brief
* XMEGA TWI master driver source file.
*
* This file contains the function implementations the XMEGA master TWI
* driver.
*
* The driver is not intended for size and/or speed critical code, since
* most functions are just a few lines of code, and the function call
* overhead would decrease code performance. The driver is intended for
* rapid prototyping and documentation purposes for getting started with
* the XMEGA TWI master module.
*
* For size and/or speed critical code, it is recommended to copy the
* function contents directly into your application instead of making
* a function call.
*
* Several functions use the following construct:
* "some_register = ... | (some_parameter ? SOME_BIT_bm : 0) | ..."
* Although the use of the ternary operator ( if ? then : else ) is
* discouraged, in some occasions the operator makes it possible to write
* pretty clean and neat code. In this driver, the construct is used to
* set or not set a configuration bit based on a boolean input parameter,
* such as the "some_parameter" in the example above.
*
* \par Application note:
* AVR1308: Using the XMEGA TWI
*
* \par Documentation
* For comprehensive code documentation, supported compilers, compiler
* settings and supported devices see readme.html
*
* \author
* Atmel Corporation: http://www.atmel.com \n
* Support email: avr@atmel.com
*
* $Revision: 1569 $
* $Date: 2008-04-22 13:03:43 +0200 (ti, 22 apr 2008) $ \n
*
* Copyright (c) 2008, 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:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. 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.
*
* 3. The name of ATMEL may not be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY ATMEL "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 EXPRESSLY AND
* SPECIFICALLY 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.
*****************************************************************************/
#include "twi_master_driver.h"
/*! \brief Initialize the TWI module.
*
* TWI module initialization function.
* Enables master read and write interrupts.
* Remember to enable interrupts globally from the main application.
*
* \param twi The TWI_Master_t struct instance.
* \param module The TWI module to use.
* \param intLevel Master interrupt level.
* \param baudRateRegisterSetting The baud rate register value.
*/
void TWI_MasterInit(TWI_Master_t *twi,
TWI_t *module,
TWI_MASTER_INTLVL_t intLevel,
uint8_t baudRateRegisterSetting)
{
twi->interface = module;
twi->interface->MASTER.CTRLA = intLevel |
TWI_MASTER_RIEN_bm |
TWI_MASTER_WIEN_bm |
TWI_MASTER_ENABLE_bm;
twi->interface->MASTER.BAUD = baudRateRegisterSetting;
twi->interface->MASTER.STATUS = TWI_MASTER_BUSSTATE_IDLE_gc;
}
/*! \brief Returns the TWI bus state.
*
* Returns the TWI bus state (type defined in device headerfile),
* unknown, idle, owner or busy.
*
* \param twi The TWI_Master_t struct instance.
*
* \retval TWI_MASTER_BUSSTATE_UNKNOWN_gc Bus state is unknown.
* \retval TWI_MASTER_BUSSTATE_IDLE_gc Bus state is idle.
* \retval TWI_MASTER_BUSSTATE_OWNER_gc Bus state is owned by the master.
* \retval TWI_MASTER_BUSSTATE_BUSY_gc Bus state is busy.
*/
TWI_MASTER_BUSSTATE_t TWI_MasterState(TWI_Master_t *twi)
{
TWI_MASTER_BUSSTATE_t twi_status;
twi_status = (TWI_MASTER_BUSSTATE_t) (twi->interface->MASTER.STATUS &
TWI_MASTER_BUSSTATE_gm);
return twi_status;
}
/*! \brief Returns true if transaction is ready.
*
* This function returns a boolean whether the TWI Master is ready
* for a new transaction.
*
* \param twi The TWI_Master_t struct instance.
*
* \retval true If transaction could be started.
* \retval false If transaction could not be started.
*/
bool TWI_MasterReady(TWI_Master_t *twi)
{
bool twi_status = (twi->status & TWIM_STATUS_READY);
return twi_status;
}
/*! \brief TWI write transaction.
*
* This function is TWI Master wrapper for a write-only transaction.
*
* \param twi The TWI_Master_t struct instance.
* \param address Slave address.
* \param writeData Pointer to data to write.
* \param bytesToWrite Number of data bytes to write.
*
* \retval true If transaction could be started.
* \retval false If transaction could not be started.
*/
bool TWI_MasterWrite(TWI_Master_t *twi,
uint8_t address,
uint8_t *writeData,
uint8_t bytesToWrite)
{
bool twi_status = TWI_MasterWriteRead(twi, address, writeData, bytesToWrite, 0);
return twi_status;
}
/*! \brief TWI read transaction.
*
* This function is a TWI Maste wrapper for read-only transaction.
*
* \param twi The TWI_Master_t struct instance.
* \param address The slave address.
* \param bytesToRead The number of bytes to read.
*
* \retval true If transaction could be started.
* \retval false If transaction could not be started.
*/
bool TWI_MasterRead(TWI_Master_t *twi,
uint8_t address,
uint8_t bytesToRead)
{
bool twi_status = TWI_MasterWriteRead(twi, address, 0, 0, bytesToRead);
return twi_status;
}
/*! \brief TWI write and/or read transaction.
*
* This function is a TWI Master write and/or read transaction. The function
* can be used to both write and/or read bytes to/from the TWI Slave in one
* transaction.
*
* \param twi The TWI_Master_t struct instance.
* \param address The slave address.
* \param writeData Pointer to data to write.
* \param bytesToWrite Number of bytes to write.
* \param bytesToRead Number of bytes to read.
*
* \retval true If transaction could be started.
* \retval false If transaction could not be started.
*/
bool TWI_MasterWriteRead(TWI_Master_t *twi,
uint8_t address,
uint8_t *writeData,
uint8_t bytesToWrite,
uint8_t bytesToRead)
{
/*Parameter sanity check. */
if (bytesToWrite > TWIM_WRITE_BUFFER_SIZE) {
return false;
}
if (bytesToRead > TWIM_READ_BUFFER_SIZE) {
return false;
}
/*Initiate transaction if bus is ready. */
if (twi->status == TWIM_STATUS_READY) {
twi->status = TWIM_STATUS_BUSY;
twi->result = TWIM_RESULT_UNKNOWN;
twi->address = address<<1;
/* Fill write data buffer. */
for (uint8_t bufferIndex=0; bufferIndex < bytesToWrite; bufferIndex++) {
twi->writeData[bufferIndex] = writeData[bufferIndex];
}
twi->bytesToWrite = bytesToWrite;
twi->bytesToRead = bytesToRead;
twi->bytesWritten = 0;
twi->bytesRead = 0;
/* If write command, send the START condition + Address +
* 'R/_W = 0'
*/
if (twi->bytesToWrite > 0) {
uint8_t writeAddress = twi->address & ~0x01;
twi->interface->MASTER.ADDR = writeAddress;
}
/* If read command, send the START condition + Address +
* 'R/_W = 1'
*/
else if (twi->bytesToRead > 0) {
uint8_t readAddress = twi->address | 0x01;
twi->interface->MASTER.ADDR = readAddress;
}
return true;
} else {
return false;
}
}
/*! \brief Common TWI master interrupt service routine.
*
* Check current status and calls the appropriate handler.
*
* \param twi The TWI_Master_t struct instance.
*/
void TWI_MasterInterruptHandler(TWI_Master_t *twi)
{
uint8_t currentStatus = twi->interface->MASTER.STATUS;
/* If arbitration lost or bus error. */
if ((currentStatus & TWI_MASTER_ARBLOST_bm) ||
(currentStatus & TWI_MASTER_BUSERR_bm)) {
TWI_MasterArbitrationLostBusErrorHandler(twi);
}
/* If master write interrupt. */
else if (currentStatus & TWI_MASTER_WIF_bm) {
TWI_MasterWriteHandler(twi);
}
/* If master read interrupt. */
else if (currentStatus & TWI_MASTER_RIF_bm) {
TWI_MasterReadHandler(twi);
}
/* If unexpected state. */
else {
TWI_MasterTransactionFinished(twi, TWIM_RESULT_FAIL);
}
}
/*! \brief TWI master arbitration lost and bus error interrupt handler.
*
* Handles TWI responses to lost arbitration and bus error.
*
* \param twi The TWI_Master_t struct instance.
*/
void TWI_MasterArbitrationLostBusErrorHandler(TWI_Master_t *twi)
{
uint8_t currentStatus = twi->interface->MASTER.STATUS;
/* If bus error. */
if (currentStatus & TWI_MASTER_BUSERR_bm) {
twi->result = TWIM_RESULT_BUS_ERROR;
}
/* If arbitration lost. */
else {
twi->result = TWIM_RESULT_ARBITRATION_LOST;
}
/* Clear interrupt flag. */
twi->interface->MASTER.STATUS = currentStatus | TWI_MASTER_ARBLOST_bm;
twi->status = TWIM_STATUS_READY;
}
/*! \brief TWI master write interrupt handler.
*
* Handles TWI transactions (master write) and responses to (N)ACK.
*
* \param twi The TWI_Master_t struct instance.
*/
void TWI_MasterWriteHandler(TWI_Master_t *twi)
{
/* Local variables used in if tests to avoid compiler warning. */
uint8_t bytesToWrite = twi->bytesToWrite;
uint8_t bytesToRead = twi->bytesToRead;
/* If NOT acknowledged (NACK) by slave cancel the transaction. */
if (twi->interface->MASTER.STATUS & TWI_MASTER_RXACK_bm) {
twi->interface->MASTER.CTRLC = TWI_MASTER_CMD_STOP_gc;
twi->result = TWIM_RESULT_NACK_RECEIVED;
twi->status = TWIM_STATUS_READY;
}
/* If more bytes to write, send data. */
else if (twi->bytesWritten < bytesToWrite) {
uint8_t data = twi->writeData[twi->bytesWritten];
twi->interface->MASTER.DATA = data;
++twi->bytesWritten;
}
/* If bytes to read, send repeated START condition + Address +
* 'R/_W = 1'
*/
else if (twi->bytesRead < bytesToRead) {
uint8_t readAddress = twi->address | 0x01;
twi->interface->MASTER.ADDR = readAddress;
}
/* If transaction finished, send STOP condition and set RESULT OK. */
else {
twi->interface->MASTER.CTRLC = TWI_MASTER_CMD_STOP_gc;
TWI_MasterTransactionFinished(twi, TWIM_RESULT_OK);
}
}
/*! \brief TWI master read interrupt handler.
*
* This is the master read interrupt handler that takes care of
* reading bytes from the TWI slave.
*
* \param twi The TWI_Master_t struct instance.
*/
void TWI_MasterReadHandler(TWI_Master_t *twi)
{
/* Fetch data if bytes to be read. */
if (twi->bytesRead < TWIM_READ_BUFFER_SIZE) {
uint8_t data = twi->interface->MASTER.DATA;
twi->readData[twi->bytesRead] = data;
twi->bytesRead++;
}
/* If buffer overflow, issue STOP and BUFFER_OVERFLOW condition. */
else {
twi->interface->MASTER.CTRLC = TWI_MASTER_CMD_STOP_gc;
TWI_MasterTransactionFinished(twi, TWIM_RESULT_BUFFER_OVERFLOW);
}
/* Local variable used in if test to avoid compiler warning. */
uint8_t bytesToRead = twi->bytesToRead;
/* If more bytes to read, issue ACK and start a byte read. */
if (twi->bytesRead < bytesToRead) {
twi->interface->MASTER.CTRLC = TWI_MASTER_CMD_RECVTRANS_gc;
}
/* If transaction finished, issue NACK and STOP condition. */
else {
twi->interface->MASTER.CTRLC = TWI_MASTER_ACKACT_bm |
TWI_MASTER_CMD_STOP_gc;
TWI_MasterTransactionFinished(twi, TWIM_RESULT_OK);
}
}
/*! \brief TWI transaction finished handler.
*
* Prepares module for new transaction.
*
* \param twi The TWI_Master_t struct instance.
* \param result The result of the operation.
*/
void TWI_MasterTransactionFinished(TWI_Master_t *twi, uint8_t result)
{
twi->result = result;
twi->status = TWIM_STATUS_READY;
}