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drivers/I2CSlave.h
- Committer:
- kevman
- Date:
- 2018-11-28
- Revision:
- 0:38ceb79fef03
File content as of revision 0:38ceb79fef03:
/* mbed Microcontroller Library * Copyright (c) 2006-2013 ARM Limited * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #ifndef MBED_I2C_SLAVE_H #define MBED_I2C_SLAVE_H #include "platform/platform.h" #if defined (DEVICE_I2CSLAVE) || defined(DOXYGEN_ONLY) #include "hal/i2c_api.h" namespace mbed { /** \addtogroup drivers */ /** An I2C Slave, used for communicating with an I2C Master device. * * @note Synchronization level: Not protected * * Example Simple I2C responder: * @code * #include <mbed.h> * * const int SLAVE_ADDRESS = 0xA0; * const char message[] = "Slave!"; * * I2CSlave slave(I2C_SDA, I2C_SCL); * * int main() { * slave.address(SLAVE_ADDRESS); * while (1) { * int operation = slave.receive(); * switch (operation) { * case I2CSlave::ReadAddressed: * int status = slave.write(message, sizeof(message)); * if (status == 0) { * printf("Written message: %s\n", message); * } else { * printf("Failed to write message.\n"); * } * break; * case I2CSlave::WriteGeneral: * int byte_read = slave.read(); * printf("Read General: %c (%d)\n", byte_read, byte_read); * break; * case I2CSlave::WriteAddressed: * int byte_read = slave.read(); * printf("Read Addressed: %c (%d)\n", byte_read, byte_read); * break; * } * } * } * @endcode * @ingroup drivers */ class I2CSlave { public: enum RxStatus { NoData = 0, ReadAddressed = 1, WriteGeneral = 2, WriteAddressed = 3 }; /** Create an I2C Slave interface, connected to the specified pins. * * @param sda I2C data line pin. * @param scl I2C clock line pin. */ I2CSlave(PinName sda, PinName scl); /** Set the frequency of the I2C interface. * * @param hz The bus frequency in Hertz. */ void frequency(int hz); /** Check if this I2C Slave has been addressed. * * @return A status indicating if the device has been addressed and how. * @retval NoData The slave has not been addressed. * @retval ReadAddressed The master has requested a read from this slave. * @retval WriteAddressed The master is writing to this slave. * @retval WriteGeneral The master is writing to all slave. */ int receive(void); /** Read specified number of bytes from an I2C master. * * @param data Pointer to the buffer to read data into. * @param length Number of bytes to read. * * @return Result of the operation. * @retval 0 If the number of bytes read is equal to length requested. * @retval nonzero On error or if the number of bytes read is less than requested. */ int read(char *data, int length); /** Read a single byte from an I2C master. * * @return The byte read. */ int read(void); /** Write to an I2C master. * * @param data Pointer to the buffer containing the data to be sent. * @param length Number of bytes to send. * * @return * @retval 0 If written all bytes successfully. * @retval nonzero On error or if the number of bytes written is less than requested. */ int write(const char *data, int length); /** Write a single byte to an I2C master. * * @param data Value to write. * * @return Result of the operation. * @retval 0 If a NACK is received. * @retval 1 If an ACK is received. * @retval 2 On timeout. */ int write(int data); /** Set the I2C slave address. * * @param address The address to set for the slave (least significant bit is ignored). * * @note If address is set to 0, the slave will only respond to the * general call address. */ void address(int address); /** Reset the I2C slave back into the known ready receiving state. */ void stop(void); #if !defined(DOXYGEN_ONLY) protected: /* Internal i2c object identifying the resources */ i2c_t _i2c; #endif //!defined(DOXYGEN_ONLY) }; } // namespace mbed #endif #endif