diff options
Diffstat (limited to 'twi_slave_driver.c')
| -rw-r--r-- | twi_slave_driver.c | 321 |
1 files changed, 321 insertions, 0 deletions
diff --git a/twi_slave_driver.c b/twi_slave_driver.c new file mode 100644 index 0000000..d6eecc2 --- /dev/null +++ b/twi_slave_driver.c @@ -0,0 +1,321 @@ +/* This file has been prepared for Doxygen automatic documentation generation.*/
+/*! \file *********************************************************************
+ *
+ * \brief
+ * XMEGA TWI slave driver source file.
+ *
+ * This file contains the function implementations the XMEGA TWI slave
+ * 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 slave 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: 2660 $
+ * $Date: 2009-08-11 12:28:58 +0200 (ti, 11 aug 2009) $ \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_slave_driver.h"
+
+
+/*! \brief Initalizes TWI slave driver structure.
+ *
+ * Initialize the instance of the TWI Slave and set the appropriate values.
+ *
+ * \param twi The TWI_Slave_t struct instance.
+ * \param module Pointer to the TWI module.
+ * \param processDataFunction Pointer to the function that handles incoming data.
+ */
+void TWI_SlaveInitializeDriver(TWI_Slave_t *twi,
+ TWI_t *module,
+ void (*processDataFunction) (void))
+{
+ twi->interface = module;
+ twi->Process_Data = processDataFunction;
+ twi->bytesReceived = 0;
+ twi->bytesSent = 0;
+ twi->status = TWIS_STATUS_READY;
+ twi->result = TWIS_RESULT_UNKNOWN;
+ twi->abort = false;
+}
+
+
+/*! \brief Initialize the TWI module.
+ *
+ * Enables interrupts on address recognition and data available.
+ * Remember to enable interrupts globally from the main application.
+ *
+ * \param twi The TWI_Slave_t struct instance.
+ * \param address Slave address for this module.
+ * \param intLevel Interrupt level for the TWI slave interrupt handler.
+ */
+void TWI_SlaveInitializeModule(TWI_Slave_t *twi,
+ uint8_t address,
+ TWI_SLAVE_INTLVL_t intLevel)
+{
+ twi->interface->SLAVE.CTRLA = intLevel |
+ TWI_SLAVE_DIEN_bm |
+ TWI_SLAVE_APIEN_bm |
+ TWI_SLAVE_ENABLE_bm;
+ twi->interface->SLAVE.ADDR = (address<<1);
+}
+
+
+/*! \brief Common TWI slave interrupt service routine.
+ *
+ * Handles all TWI transactions and responses to address match, data reception,
+ * data transmission, bus error and data collision.
+ *
+ * \param twi The TWI_Slave_t struct instance.
+ */
+void TWI_SlaveInterruptHandler(TWI_Slave_t *twi)
+{
+ uint8_t currentStatus = twi->interface->SLAVE.STATUS;
+
+ /* If bus error. */
+ if (currentStatus & TWI_SLAVE_BUSERR_bm) {
+ twi->bytesReceived = 0;
+ twi->bytesSent = 0;
+ twi->result = TWIS_RESULT_BUS_ERROR;
+ twi->status = TWIS_STATUS_READY;
+ }
+
+ /* If transmit collision. */
+ else if (currentStatus & TWI_SLAVE_COLL_bm) {
+ twi->bytesReceived = 0;
+ twi->bytesSent = 0;
+ twi->result = TWIS_RESULT_TRANSMIT_COLLISION;
+ twi->status = TWIS_STATUS_READY;
+ }
+
+ /* If address match. */
+ else if ((currentStatus & TWI_SLAVE_APIF_bm) &&
+ (currentStatus & TWI_SLAVE_AP_bm)) {
+
+ TWI_SlaveAddressMatchHandler(twi);
+ }
+
+ /* If stop (only enabled through slave read transaction). */
+ else if (currentStatus & TWI_SLAVE_APIF_bm) {
+ TWI_SlaveStopHandler(twi);
+ }
+
+ /* If data interrupt. */
+ else if (currentStatus & TWI_SLAVE_DIF_bm) {
+ TWI_SlaveDataHandler(twi);
+ }
+
+ /* If unexpected state. */
+ else {
+ TWI_SlaveTransactionFinished(twi, TWIS_RESULT_FAIL);
+ }
+}
+
+/*! \brief TWI address match interrupt handler.
+ *
+ * Prepares TWI module for transaction when an address match occures.
+ *
+ * \param twi The TWI_Slave_t struct instance.
+ */
+void TWI_SlaveAddressMatchHandler(TWI_Slave_t *twi)
+{
+ /* If application signalling need to abort (error occured). */
+ if (twi->abort) {
+ twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_COMPTRANS_gc;
+ TWI_SlaveTransactionFinished(twi, TWIS_RESULT_ABORTED);
+ twi->abort = false;
+ } else {
+ twi->status = TWIS_STATUS_BUSY;
+ twi->result = TWIS_RESULT_UNKNOWN;
+
+ /* Disable stop interrupt. */
+ uint8_t currentCtrlA = twi->interface->SLAVE.CTRLA;
+ twi->interface->SLAVE.CTRLA = currentCtrlA & ~TWI_SLAVE_PIEN_bm;
+
+ twi->bytesReceived = 0;
+ twi->bytesSent = 0;
+
+ /* Send ACK, wait for data interrupt. */
+ twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_RESPONSE_gc;
+ }
+}
+
+
+/*! \brief TWI stop condition interrupt handler.
+ *
+ * \param twi The TWI_Slave_t struct instance.
+ */
+void TWI_SlaveStopHandler(TWI_Slave_t *twi)
+{
+ /* Disable stop interrupt. */
+ uint8_t currentCtrlA = twi->interface->SLAVE.CTRLA;
+ twi->interface->SLAVE.CTRLA = currentCtrlA & ~TWI_SLAVE_PIEN_bm;
+
+ /* Clear APIF, according to flowchart don't ACK or NACK */
+ uint8_t currentStatus = twi->interface->SLAVE.STATUS;
+ twi->interface->SLAVE.STATUS = currentStatus | TWI_SLAVE_APIF_bm;
+
+ TWI_SlaveTransactionFinished(twi, TWIS_RESULT_OK);
+
+}
+
+
+/*! \brief TWI data interrupt handler.
+ *
+ * Calls the appropriate slave read or write handler.
+ *
+ * \param twi The TWI_Slave_t struct instance.
+ */
+void TWI_SlaveDataHandler(TWI_Slave_t *twi)
+{
+ if (twi->interface->SLAVE.STATUS & TWI_SLAVE_DIR_bm) {
+ TWI_SlaveWriteHandler(twi);
+ } else {
+ TWI_SlaveReadHandler(twi);
+ }
+}
+
+
+/*! \brief TWI slave read interrupt handler.
+ *
+ * Handles TWI slave read transactions and responses.
+ *
+ * \param twi The TWI_Slave_t struct instance.
+ */
+void TWI_SlaveReadHandler(TWI_Slave_t *twi)
+{
+ /* Enable stop interrupt. */
+ uint8_t currentCtrlA = twi->interface->SLAVE.CTRLA;
+ twi->interface->SLAVE.CTRLA = currentCtrlA | TWI_SLAVE_PIEN_bm;
+
+ /* If free space in buffer. */
+ if (twi->bytesReceived < TWIS_RECEIVE_BUFFER_SIZE) {
+ /* Fetch data */
+ uint8_t data = twi->interface->SLAVE.DATA;
+ twi->receivedData[twi->bytesReceived] = data;
+
+ /* Process data. */
+ twi->Process_Data();
+
+ twi->bytesReceived++;
+
+ /* If application signalling need to abort (error occured),
+ * complete transaction and wait for next START. Otherwise
+ * send ACK and wait for data interrupt.
+ */
+ if (twi->abort) {
+ twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_COMPTRANS_gc;
+ TWI_SlaveTransactionFinished(twi, TWIS_RESULT_ABORTED);
+ twi->abort = false;
+ } else {
+ twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_RESPONSE_gc;
+ }
+ }
+ /* If buffer overflow, send NACK and wait for next START. Set
+ * result buffer overflow.
+ */
+ else {
+ twi->interface->SLAVE.CTRLB = TWI_SLAVE_ACKACT_bm |
+ TWI_SLAVE_CMD_COMPTRANS_gc;
+ TWI_SlaveTransactionFinished(twi, TWIS_RESULT_BUFFER_OVERFLOW);
+ }
+}
+
+
+/*! \brief TWI slave write interrupt handler.
+ *
+ * Handles TWI slave write transactions and responses.
+ *
+ * \param twi The TWI_Slave_t struct instance.
+ */
+void TWI_SlaveWriteHandler(TWI_Slave_t *twi)
+{
+ /* If NACK, slave write transaction finished. */
+ if ((twi->bytesSent > 0) && (twi->interface->SLAVE.STATUS &
+ TWI_SLAVE_RXACK_bm)) {
+
+ twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_COMPTRANS_gc;
+ TWI_SlaveTransactionFinished(twi, TWIS_RESULT_OK);
+ }
+ /* If ACK, master expects more data. */
+ else {
+ if (twi->bytesSent < TWIS_SEND_BUFFER_SIZE) {
+ uint8_t data = twi->sendData[twi->bytesSent];
+ twi->interface->SLAVE.DATA = data;
+ twi->bytesSent++;
+
+ /* Send data, wait for data interrupt. */
+ twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_RESPONSE_gc;
+ }
+ /* If buffer overflow. */
+ else {
+ twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_COMPTRANS_gc;
+ TWI_SlaveTransactionFinished(twi, TWIS_RESULT_BUFFER_OVERFLOW);
+ }
+ }
+}
+
+
+/*! \brief TWI transaction finished function.
+ *
+ * Prepares module for new transaction.
+ *
+ * \param twi The TWI_Slave_t struct instance.
+ * \param result The result of the transaction.
+ */
+void TWI_SlaveTransactionFinished(TWI_Slave_t *twi, uint8_t result)
+{
+ twi->result = result;
+ twi->status = TWIS_STATUS_READY;
+}
|