Mbed OS Reference | i2c_api.h Source File

 
 /** \addtogroup hal */
 /** @{*/
 /* 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.
  * 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_API_H
 #define MBED_I2C_API_H
 
 #include "device.h"
 #include "pinmap.h"
 #include "hal/buffer.h"
 
 #if DEVICE_I2C_ASYNCH
 #include "hal/dma_api.h"
 #endif
 
 #if DEVICE_I2C
 
 /**
  * @defgroup hal_I2CEvents I2C Events Macros
  *
  * @{
  */
 #define I2C_EVENT_ERROR               (1 << 1)
 #define I2C_EVENT_ERROR_NO_SLAVE      (1 << 2)
 #define I2C_EVENT_TRANSFER_COMPLETE   (1 << 3)
 #define I2C_EVENT_TRANSFER_EARLY_NACK (1 << 4)
 #define I2C_EVENT_ALL                 (I2C_EVENT_ERROR |  I2C_EVENT_TRANSFER_COMPLETE | I2C_EVENT_ERROR_NO_SLAVE | I2C_EVENT_TRANSFER_EARLY_NACK)
 
 /**@}*/
 
 #if DEVICE_I2C_ASYNCH
 /** Asynch I2C HAL structure
  */
 typedef struct {
     struct i2c_s    i2c;     /**< Target specific I2C structure */
     struct buffer_s tx_buff; /**< Tx buffer */
     struct buffer_s rx_buff; /**< Rx buffer */
 } i2c_t;
 
 #else
 /** Non-asynch I2C HAL structure
  */
 typedef struct i2c_s i2c_t;
 
 #endif
 
 enum {
     I2C_ERROR_NO_SLAVE = -1,
     I2C_ERROR_BUS_BUSY = -2
 };
 
 typedef struct {
     int peripheral;
     PinName sda_pin;
     int sda_function;
     PinName scl_pin;
     int scl_function;
 } i2c_pinmap_t;
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 /**
  * \defgroup hal_GeneralI2C I2C Configuration Functions
  *
  * # Defined behavior
  * * ::i2c_init initializes i2c_t control structure
  * * ::i2c_init configures the pins used by I2C
  * * ::i2c_free returns the pins owned by the I2C object to their reset state
  * * ::i2c_frequency configure the I2C frequency
  * * ::i2c_start sends START command
  * * ::i2c_read reads `length` bytes from the I2C slave specified by `address` to the `data` buffer
  * * ::i2c_read reads generates a stop condition on the bus at the end of the transfer if `stop` parameter is non-zero
  * * ::i2c_read reads returns the number of symbols received from the bus
  * * ::i2c_write writes `length` bytes to the I2C slave specified by `address` from the `data` buffer
  * * ::i2c_write generates a stop condition on the bus at the end of the transfer if `stop` parameter is non-zero
  * * ::i2c_write returns zero on success, error code otherwise
  * * ::i2c_reset resets the I2C peripheral
  * * ::i2c_byte_read reads and return one byte from the specfied I2C slave
  * * ::i2c_byte_read uses `last` parameter to inform the slave that all bytes have been read
  * * ::i2c_byte_write writes one byte to the specified I2C slave
  * * ::i2c_byte_write returns 0 if NAK was received, 1 if ACK was received, 2 for timeout
  * * ::i2c_slave_mode enables/disables I2S slave mode
  * * ::i2c_slave_receive returns: 1 - read addresses, 2 - write to all slaves, 3 write addressed, 0 - the slave has not been addressed
  * * ::i2c_slave_read reads `length` bytes from the I2C master to the `data` buffer
  * * ::i2c_slave_read returns non-zero if a value is available, 0 otherwise
  * * ::i2c_slave_write writes `length` bytes to the I2C master from the `data` buffer
  * * ::i2c_slave_write returns non-zero if a value is available, 0 otherwise
  * * ::i2c_slave_address configures I2C slave address
  * * ::i2c_transfer_asynch starts I2C asynchronous transfer
  * * ::i2c_transfer_asynch writes `tx_length` bytes to the I2C slave specified by `address` from the `tx` buffer
  * * ::i2c_transfer_asynch reads `rx_length` bytes from the I2C slave specified by `address` to the `rx` buffer
  * * ::i2c_transfer_asynch generates a stop condition on the bus at the end of the transfer if `stop` parameter is non-zero
  * * The callback given to ::i2c_transfer_asynch is invoked when the transfer completes
  * * ::i2c_transfer_asynch specifies the logical OR of events to be registered
  * * The ::i2c_transfer_asynch function may use the `DMAUsage` hint to select the appropriate async algorithm
  * * ::i2c_irq_handler_asynch returns event flags if a transfer termination condition was met, otherwise returns 0.
  * * ::i2c_active returns non-zero if the I2C module is active or 0 if it is not
  * * ::i2c_abort_asynch aborts an on-going async transfer
  *
  * # Undefined behavior
  * * Calling ::i2c_init multiple times on the same `i2c_t`
  * * Calling any function other than ::i2c_init on a non-initialized `i2c_t`
  * * Initialising the `I2C` peripheral with invalid `SDA` and `SCL` pins.
  * * Passing pins that cannot be on the same peripheral
  * * Passing an invalid pointer as `obj` to any function
  * * Use of a `null` pointer as an argument to any function.
  * * Initialising the peripheral in slave mode if slave mode is not supported
  * * Operating the peripheral in slave mode without first specifying and address using ::i2c_slave_address
  * * Setting an address using i2c_slave_address after initialising the peripheral in master mode
  * * Setting an address to an `I2C` reserved value
  * * Specifying an invalid address when calling any `read` or `write` functions
  * * Setting the length of the transfer or receive buffers to larger than the buffers are
  * * Passing an invalid pointer as `handler`
  * * Calling ::i2c_abort_async when no transfer is currently in progress
  *
  *
  * @{
  */
 
 /**
  * \defgroup hal_GeneralI2C_tests I2C hal tests
  * The I2C HAL tests ensure driver conformance to defined behaviour.
  *
  * To run the I2C hal tests use the command:
  *
  *     mbed test -t <toolchain> -m <target> -n tests-mbed_hal_fpga_ci_test_shield-i2c
  *
  */
 
 /** Initialize the I2C peripheral. It sets the default parameters for I2C
  *  peripheral, and configures its specifieds pins.
  *
  *  @param obj  The I2C object
  *  @param pinmap  Pinmap pointer to structure which holds static pinmap
  */
 void i2c_init_direct(i2c_t *obj, const i2c_pinmap_t *pinmap);
 
 /** Initialize the I2C peripheral. It sets the default parameters for I2C
  *  peripheral, and configures its specifieds pins.
  *
  *  @param obj  The I2C object
  *  @param sda  The sda pin
  *  @param scl  The scl pin
  */
 void i2c_init(i2c_t *obj, PinName sda, PinName scl);
 
 /** Release a I2C object
  *
  * Return the pins owned by the I2C object to their reset state
  * @param obj The I2C object to deinitialize
  */
 void i2c_free(i2c_t *obj);
 
 /** Configure the I2C frequency
  *
  *  @param obj The I2C object
  *  @param hz  Frequency in Hz
  */
 void i2c_frequency(i2c_t *obj, int hz);
 
 /** Send START command
  *
  *  @param obj The I2C object
  */
 int  i2c_start(i2c_t *obj);
 
 /** Send STOP command
  *
  *  @param obj The I2C object
  */
 int  i2c_stop(i2c_t *obj);
 
 /** Blocking reading data
  *
  *  @param obj     The I2C object
  *  @param address 7-bit address (last bit is 1)
  *  @param data    The buffer for receiving
  *  @param length  Number of bytes to read
  *  @param stop    Stop to be generated after the transfer is done
  *  @return Number of read bytes
  */
 int i2c_read(i2c_t *obj, int address, char *data, int length, int stop);
 
 /** Blocking sending data
  *
  *  @param obj     The I2C object
  *  @param address 7-bit address (last bit is 0)
  *  @param data    The buffer for sending
  *  @param length  Number of bytes to write
  *  @param stop    Stop to be generated after the transfer is done
  *  @return
  *      zero or non-zero - Number of written bytes
  *      negative - I2C_ERROR_XXX status
  */
 int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop);
 
 /** Reset I2C peripheral. TODO: The action here. Most of the implementation sends stop()
  *
  *  @param obj The I2C object
  */
 void i2c_reset(i2c_t *obj);
 
 /** Read one byte
  *
  *  @param obj The I2C object
  *  @param last Acknoledge
  *  @return The read byte
  */
 int i2c_byte_read(i2c_t *obj, int last);
 
 /** Write one byte
  *
  *  @param obj The I2C object
  *  @param data Byte to be written
  *  @return 0 if NAK was received, 1 if ACK was received, 2 for timeout.
  */
 int i2c_byte_write(i2c_t *obj, int data);
 
 /** Get the pins that support I2C SDA
  *
  * Return a PinMap array of pins that support I2C SDA in
  * master mode. The array is terminated with {NC, NC, 0}.
  *
  * @return PinMap array
  */
 const PinMap *i2c_master_sda_pinmap(void);
 
 /** Get the pins that support I2C SCL
  *
  * Return a PinMap array of pins that support I2C SCL in
  * master mode. The array is terminated with {NC, NC, 0}.
  *
  * @return PinMap array
  */
 const PinMap *i2c_master_scl_pinmap(void);
 
 /** Get the pins that support I2C SDA
  *
  * Return a PinMap array of pins that support I2C SDA in
  * slave mode. The array is terminated with {NC, NC, 0}.
  *
  * @return PinMap array
  */
 const PinMap *i2c_slave_sda_pinmap(void);
 
 /** Get the pins that support I2C SCL
  *
  * Return a PinMap array of pins that support I2C SCL in
  * slave mode. The array is terminated with {NC, NC, 0}.
  *
  * @return PinMap array
  */
 const PinMap *i2c_slave_scl_pinmap(void);
 
 /**@}*/
 
 #if DEVICE_I2CSLAVE
 
 /**
  * \defgroup SynchI2C Synchronous I2C Hardware Abstraction Layer for slave
  * @{
  */
 
 /** Configure I2C as slave or master.
  *  @param obj The I2C object
  *  @param enable_slave Enable i2c hardware so you can receive events with ::i2c_slave_receive
  *  @return non-zero if a value is available
  */
 void i2c_slave_mode(i2c_t *obj, int enable_slave);
 
 /** Check to see if the I2C slave has been addressed.
  *  @param obj The I2C object
  *  @return The status - 1 - read addresses, 2 - write to all slaves,
  *         3 write addressed, 0 - the slave has not been addressed
  */
 int  i2c_slave_receive(i2c_t *obj);
 
 /** Configure I2C as slave or master.
  *  @param obj The I2C object
  *  @param data    The buffer for receiving
  *  @param length  Number of bytes to read
  *  @return non-zero if a value is available
  */
 int  i2c_slave_read(i2c_t *obj, char *data, int length);
 
 /** Configure I2C as slave or master.
  *  @param obj The I2C object
  *  @param data    The buffer for sending
  *  @param length  Number of bytes to write
  *  @return non-zero if a value is available
  */
 int  i2c_slave_write(i2c_t *obj, const char *data, int length);
 
 /** Configure I2C address.
  *  @param obj     The I2C object
  *  @param idx     Currently not used
  *  @param address The address to be set
  *  @param mask    Currently not used
  */
 void i2c_slave_address(i2c_t *obj, int idx, uint32_t address, uint32_t mask);
 
 #endif
 
 /**@}*/
 
 #if DEVICE_I2C_ASYNCH
 
 /**
  * \defgroup hal_AsynchI2C Asynchronous I2C Hardware Abstraction Layer
  * @{
  */
 
 /** Start I2C asynchronous transfer
  *
  *  @param obj       The I2C object
  *  @param tx        The transmit buffer
  *  @param tx_length The number of bytes to transmit
  *  @param rx        The receive buffer
  *  @param rx_length The number of bytes to receive
  *  @param address   The address to be set - 7bit or 9bit
  *  @param stop      If true, stop will be generated after the transfer is done
  *  @param handler   The I2C IRQ handler to be set
  *  @param event     Event mask for the transfer. See \ref hal_I2CEvents
  *  @param hint      DMA hint usage
  */
 void i2c_transfer_asynch(i2c_t *obj, const void *tx, size_t tx_length, void *rx, size_t rx_length, uint32_t address, uint32_t stop, uint32_t handler, uint32_t event, DMAUsage hint);
 
 /** The asynchronous IRQ handler
  *
  *  @param obj The I2C object which holds the transfer information
  *  @return Event flags if a transfer termination condition was met, otherwise return 0.
  */
 uint32_t i2c_irq_handler_asynch(i2c_t *obj);
 
 /** Attempts to determine if the I2C peripheral is already in use
  *
  *  @param obj The I2C object
  *  @return Non-zero if the I2C module is active or zero if it is not
  */
 uint8_t i2c_active(i2c_t *obj);
 
 /** Abort asynchronous transfer
  *
  *  This function does not perform any check - that should happen in upper layers.
  *  @param obj The I2C object
  */
 void i2c_abort_asynch(i2c_t *obj);
 
 #endif
 
 /**@}*/
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif
 
 #endif
 
 /** @}*/
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