Diff: mbed/drivers/I2C.h

Revision:

6:40e873bbc5f7

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed/drivers/I2C.h	Thu Mar 16 21:58:09 2017 +0900
@@ -0,0 +1,198 @@
+/* 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/platform.h"
+
+#if DEVICE_I2C
+
+#include "hal/i2c_api.h"
+#include "platform/SingletonPtr.h"
+#include "platform/PlatformMutex.h"
+
+#if DEVICE_I2C_ASYNCH
+#include "platform/CThunk.h"
+#include "hal/dma_api.h"
+#include "platform/FunctionPointer.h"
+#endif
+
+namespace mbed {
+/** \addtogroup drivers */
+/** @{*/
+
+/** An I2C Master, used for communicating with I2C slave devices
+ *
+ * @Note Synchronization level: Thread safe
+ *
+ * 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 or non-zero - written number of bytes,
+     *      negative - I2C_ERROR_XXX status
+     */
+    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
+     *    '0' - NAK was received
+     *    '1' - ACK was received,
+     *    '2' - timeout
+     */
+    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);
+
+    /** Acquire exclusive access to this I2C bus
+     */
+    virtual void lock(void);
+
+    /** Release exclusive access to this I2C bus
+     */
+    virtual void unlock(void);
+
+    virtual ~I2C() {
+        // Do nothing
+    }
+
+#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;
+    static SingletonPtr<PlatformMutex> _mutex;
+};
+
+} // namespace mbed
+
+#endif
+
+#endif
+
+/** @}*/