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Diff: drivers/I2CSlave.h
- Revision:
- 0:38ceb79fef03
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/drivers/I2CSlave.h Wed Nov 28 15:10:15 2018 +0000 @@ -0,0 +1,166 @@ +/* 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