The official Mbed 2 C/C++ SDK provides the software platform and libraries to build your applications.
Dependents: hello SerialTestv11 SerialTestv12 Sierpinski ... more
mbed 2
This is the mbed 2 library. If you'd like to learn about Mbed OS please see the mbed-os docs.
Diff: drivers/I2C.h
- Revision:
- 172:65be27845400
- Parent:
- 171:3a7713b1edbc
--- a/drivers/I2C.h Thu Nov 08 11:45:42 2018 +0000 +++ b/drivers/I2C.h Wed Feb 20 20:53:29 2019 +0000 @@ -1,5 +1,6 @@ /* mbed Microcontroller Library * Copyright (c) 2006-2015 ARM Limited + * SPDX-License-Identifier: Apache-2.0 * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -17,8 +18,9 @@ #define MBED_I2C_H #include "platform/platform.h" +#include "hal/gpio_api.h" -#if defined (DEVICE_I2C) || defined(DOXYGEN_ONLY) +#if DEVICE_I2C || defined(DOXYGEN_ONLY) #include "hal/i2c_api.h" #include "platform/SingletonPtr.h" @@ -40,16 +42,32 @@ * * Example: * @code - * // Read from I2C slave at address 0x62 - * + * Read temperature from LM75BD * #include "mbed.h" - * - * I2C i2c(p28, p27); + * I2C i2c(I2C_SDA , I2C_SCL); + * const int addr7bit = 0x48; // 7-bit I2C address + * const int addr8bit = 0x48 << 1; // 8-bit I2C address, 0x90 * * int main() { - * int address = 0x62; - * char data[2]; - * i2c.read(address, data, 2); + * char cmd[2]; + * while (1) { + * cmd[0] = 0x01; + * cmd[1] = 0x00; + * + * // read and write takes the 8-bit version of the address. + * // set up configuration register (at 0x01) + * i2c.write(addr8bit, cmd, 2); + * + * wait(0.5); + * + * // read temperature register + * cmd[0] = 0x00; + * i2c.write(addr8bit, cmd, 1); + * i2c.read( addr8bit, cmd, 2); + * + * float tmp = (float((cmd[0]<<8)|cmd[1]) / 256.0); + * printf("Temp = %.2f\n", tmp); + * } * } * @endcode * @ingroup drivers @@ -91,10 +109,11 @@ * @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 + * default value is false. * * @returns * 0 on success (ack), - * non-0 on failure (nack) + * nonzero on failure (nack) */ int read(int address, char *data, int length, bool repeated = false); @@ -116,10 +135,11 @@ * @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 + * default value is false. * * @returns * 0 on success (ack), - * non-0 on failure (nack) + * nonzero on failure (nack) */ int write(int address, const char *data, int length, bool repeated = false); @@ -136,7 +156,6 @@ /** Creates a start condition on the I2C bus */ - void start(void); /** Creates a stop condition on the I2C bus @@ -158,26 +177,29 @@ #if DEVICE_I2C_ASYNCH - /** Start non-blocking I2C transfer. + /** Start nonblocking I2C transfer. * * This function locks the deep sleep until any event has occurred * * @param address 8/10 bit I2C slave address * @param tx_buffer The TX buffer with data to be transferred * @param tx_length The length of TX buffer in bytes - * @param rx_buffer The RX buffer which is used for received data + * @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 + * default value is false. + * + * @returns 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 + /** Abort the ongoing I2C transfer */ void abort_transfer(); +#if !defined(DOXYGEN_ONLY) protected: /** Lock deep sleep only if it is not yet locked */ void lock_deep_sleep(); @@ -191,14 +213,33 @@ DMAUsage _usage; bool _deep_sleep_locked; #endif +#endif +#if !defined(DOXYGEN_ONLY) protected: void aquire(); i2c_t _i2c; static I2C *_owner; - int _hz; + int _hz; static SingletonPtr<PlatformMutex> _mutex; + PinName _sda; + PinName _scl; + +private: + /** Recover I2C bus, when stuck with SDA low + * @note : Initialization of I2C bus is required after this API. + * + * @param sda I2C data line pin + * @param scl I2C clock line pin + * + * @returns + * '0' - Successfully recovered + * 'I2C_ERROR_BUS_BUSY' - In case of failure + * + */ + int recover(PinName sda, PinName scl); +#endif }; } // namespace mbed