From bbc microbit library
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I2C.h
- Committer:
- jamesadevine
- Date:
- 2016-04-07
- Revision:
- 0:e1a608bb55e8
File content as of revision 0:e1a608bb55e8:
/* mbed Microcontroller Library * Copyright (c) 2006-2015 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_H #define MBED_I2C_H #include "platform.h" #if DEVICE_I2C #include "i2c_api.h" #if DEVICE_I2C_ASYNCH #include "CThunk.h" #include "dma_api.h" #include "FunctionPointer.h" #endif namespace mbed { /** An I2C Master, used for communicating with I2C slave devices * * Example: * @code * // Read from I2C slave at address 0x62 * * #include "mbed.h" * * I2C i2c(p28, p27); * * int main() { * int address = 0x62; * char data[2]; * i2c.read(address, data, 2); * } * @endcode */ class I2C { public: enum RxStatus { NoData, MasterGeneralCall, MasterWrite, MasterRead }; enum Acknowledge { NoACK = 0, ACK = 1 }; /** Create an I2C Master interface, connected to the specified pins * * @param sda I2C data line pin * @param scl I2C clock line pin */ I2C(PinName sda, PinName scl); /** Set the frequency of the I2C interface * * @param hz The bus frequency in hertz */ void frequency(int hz); /** Read from an I2C slave * * Performs a complete read transaction. The bottom bit of * the address is forced to 1 to indicate a read. * * @param address 8-bit I2C slave address [ addr | 1 ] * @param data Pointer to the byte-array to read data in to * @param length Number of bytes to read * @param repeated Repeated start, true - don't send stop at end * * @returns * 0 on success (ack), * non-0 on failure (nack) */ int read(int address, char *data, int length, bool repeated = false); /** Read a single byte from the I2C bus * * @param ack indicates if the byte is to be acknowledged (1 = acknowledge) * * @returns * the byte read */ int read(int ack); /** Write to an I2C slave * * Performs a complete write transaction. The bottom bit of * the address is forced to 0 to indicate a write. * * @param address 8-bit I2C slave address [ addr | 0 ] * @param data Pointer to the byte-array data to send * @param length Number of bytes to send * @param repeated Repeated start, true - do not send stop at end * * @returns * 0 on success (ack), * non-0 on failure (nack) */ int write(int address, const char *data, int length, bool repeated = false); /** Write single byte out on the I2C bus * * @param data data to write out on bus * * @returns * '1' if an ACK was received, * '0' otherwise */ int write(int data); /** Creates a start condition on the I2C bus */ void start(void); /** Creates a stop condition on the I2C bus */ void stop(void); #if DEVICE_I2C_ASYNCH /** Start non-blocking I2C transfer. * * @param address 8/10 bit I2c slave address * @param tx_buffer The TX buffer with data to be transfered * @param tx_length The length of TX buffer in bytes * @param rx_buffer The RX buffer which is used for received data * @param rx_length The length of RX buffer in bytes * @param event The logical OR of events to modify * @param callback The event callback function * @param repeated Repeated start, true - do not send stop at end * @return Zero if the transfer has started, or -1 if I2C peripheral is busy */ int transfer(int address, const char *tx_buffer, int tx_length, char *rx_buffer, int rx_length, const event_callback_t& callback, int event = I2C_EVENT_TRANSFER_COMPLETE, bool repeated = false); /** Abort the on-going I2C transfer */ void abort_transfer(); protected: void irq_handler_asynch(void); event_callback_t _callback; CThunk<I2C> _irq; DMAUsage _usage; #endif protected: void aquire(); i2c_t _i2c; static I2C *_owner; int _hz; }; } // namespace mbed #endif #endif