mirror of https://github.com/ARMmbed/mbed-os.git
266 lines
7.0 KiB
C++
266 lines
7.0 KiB
C++
/* mbed Microcontroller Library
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* Copyright (c) 2006-2019 ARM Limited
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef MBED_I2C_H
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#define MBED_I2C_H
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#include "platform/platform.h"
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#include "hal/gpio_api.h"
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#if DEVICE_I2C || defined(DOXYGEN_ONLY)
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#include "hal/i2c_api.h"
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#include "platform/SingletonPtr.h"
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#include "platform/PlatformMutex.h"
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#include "platform/NonCopyable.h"
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#if DEVICE_I2C_ASYNCH
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#include "platform/CThunk.h"
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#include "hal/dma_api.h"
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#include "platform/Callback.h"
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#endif
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namespace mbed {
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/** \defgroup drivers-public-api-i2c I2C
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* \ingroup drivers-public-api
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*/
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/**
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* \defgroup drivers_I2C I2C class
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* \ingroup drivers-public-api-i2c
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* @{
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*/
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/** An I2C Master, used for communicating with I2C slave devices
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*
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* @note Synchronization level: Thread safe
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*
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* Example:
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* @code
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* Read temperature from LM75BD
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* #include "mbed.h"
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* I2C i2c(I2C_SDA , I2C_SCL);
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* const int addr7bit = 0x48; // 7-bit I2C address
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* const int addr8bit = 0x48 << 1; // 8-bit I2C address, 0x90
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*
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* int main() {
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* char cmd[2];
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* while (1) {
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* cmd[0] = 0x01;
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* cmd[1] = 0x00;
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*
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* // read and write takes the 8-bit version of the address.
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* // set up configuration register (at 0x01)
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* i2c.write(addr8bit, cmd, 2);
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*
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* wait(0.5);
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*
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* // read temperature register
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* cmd[0] = 0x00;
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* i2c.write(addr8bit, cmd, 1);
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* i2c.read( addr8bit, cmd, 2);
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*
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* float tmp = (float((cmd[0]<<8)|cmd[1]) / 256.0);
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* printf("Temp = %.2f\n", tmp);
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* }
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* }
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* @endcode
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*/
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class I2C : private NonCopyable<I2C> {
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public:
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enum RxStatus {
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NoData,
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MasterGeneralCall,
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MasterWrite,
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MasterRead
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};
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enum Acknowledge {
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NoACK = 0,
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ACK = 1
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};
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/** Create an I2C Master interface, connected to the specified pins
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*
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* @param sda I2C data line pin
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* @param scl I2C clock line pin
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*/
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I2C(PinName sda, PinName scl);
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/** Create an I2C Master interface, connected to the specified pins
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*
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* @param static_pinmap reference to structure which holds static pinmap.
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*/
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I2C(const i2c_pinmap_t &static_pinmap);
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I2C(const i2c_pinmap_t &&) = delete; // prevent passing of temporary objects
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/** Set the frequency of the I2C interface
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*
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* @param hz The bus frequency in hertz
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*/
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void frequency(int hz);
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/** Read from an I2C slave
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*
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* Performs a complete read transaction. The bottom bit of
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* the address is forced to 1 to indicate a read.
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*
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* @param address 8-bit I2C slave address [ addr | 1 ]
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* @param data Pointer to the byte-array to read data in to
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* @param length Number of bytes to read
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* @param repeated Repeated start, true - don't send stop at end
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* default value is false.
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*
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* @returns
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* 0 on success (ack),
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* nonzero on failure (nack)
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*/
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int read(int address, char *data, int length, bool repeated = false);
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/** Read a single byte from the I2C bus
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*
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* @param ack indicates if the byte is to be acknowledged (1 = acknowledge)
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*
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* @returns
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* the byte read
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*/
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int read(int ack);
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/** Write to an I2C slave
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*
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* Performs a complete write transaction. The bottom bit of
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* the address is forced to 0 to indicate a write.
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*
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* @param address 8-bit I2C slave address [ addr | 0 ]
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* @param data Pointer to the byte-array data to send
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* @param length Number of bytes to send
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* @param repeated Repeated start, true - do not send stop at end
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* default value is false.
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*
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* @returns
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* 0 on success (ack),
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* nonzero on failure (nack)
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*/
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int write(int address, const char *data, int length, bool repeated = false);
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/** Write single byte out on the I2C bus
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*
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* @param data data to write out on bus
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*
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* @returns
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* '0' - NAK was received
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* '1' - ACK was received,
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* '2' - timeout
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*/
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int write(int data);
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/** Creates a start condition on the I2C bus
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*/
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void start(void);
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/** Creates a stop condition on the I2C bus
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*/
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void stop(void);
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/** Acquire exclusive access to this I2C bus
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*/
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virtual void lock(void);
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/** Release exclusive access to this I2C bus
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*/
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virtual void unlock(void);
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virtual ~I2C()
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{
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// Do nothing
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}
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#if DEVICE_I2C_ASYNCH
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/** Start nonblocking I2C transfer.
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*
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* This function locks the deep sleep until any event has occurred
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*
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* @param address 8/10 bit I2C slave address
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* @param tx_buffer The TX buffer with data to be transferred
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* @param tx_length The length of TX buffer in bytes
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* @param rx_buffer The RX buffer, which is used for received data
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* @param rx_length The length of RX buffer in bytes
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* @param event The logical OR of events to modify
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* @param callback The event callback function
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* @param repeated Repeated start, true - do not send stop at end
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* default value is false.
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*
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* @returns Zero if the transfer has started, or -1 if I2C peripheral is busy
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*/
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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);
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/** Abort the ongoing I2C transfer
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*/
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void abort_transfer();
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#if !defined(DOXYGEN_ONLY)
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protected:
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/** Lock deep sleep only if it is not yet locked */
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void lock_deep_sleep();
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/** Unlock deep sleep only if it has been locked */
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void unlock_deep_sleep();
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void irq_handler_asynch(void);
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event_callback_t _callback;
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CThunk<I2C> _irq;
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DMAUsage _usage;
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bool _deep_sleep_locked;
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#endif
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#endif
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#if !defined(DOXYGEN_ONLY)
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protected:
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void aquire();
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i2c_t _i2c;
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static I2C *_owner;
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int _hz;
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static SingletonPtr<PlatformMutex> _mutex;
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PinName _sda;
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PinName _scl;
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private:
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/** Recover I2C bus, when stuck with SDA low
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* @note : Initialization of I2C bus is required after this API.
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*
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* @param sda I2C data line pin
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* @param scl I2C clock line pin
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*
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* @returns
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* '0' - Successfully recovered
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* 'I2C_ERROR_BUS_BUSY' - In case of failure
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*
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*/
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int recover(PinName sda, PinName scl);
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#endif
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};
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/** @}*/
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} // namespace mbed
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#endif
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#endif
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