tmk_core/tool/mbed/mbed-sdk/libraries/mbed/api/I2C.h

   1 /* mbed Microcontroller Library
   2  * Copyright (c) 2006-2013 ARM Limited
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 #ifndef MBED_I2C_H
  17 #define MBED_I2C_H
  18
  19 #include "platform.h"
  20
  21 #if DEVICE_I2C
  22
  23 #include "i2c_api.h"
  24
  25 namespace mbed {
  26
  27 /** An I2C Master, used for communicating with I2C slave devices
  28  *
  29  * Example:
  30  * @code
  31  * // Read from I2C slave at address 0x62
  32  *
  33  * #include "mbed.h"
  34  *
  35  * I2C i2c(p28, p27);
  36  *
  37  * int main() {
  38  *     int address = 0x62;
  39  *     char data[2];
  40  *     i2c.read(address, data, 2);
  41  * }
  42  * @endcode
  43  */
  44 class I2C {
  45
  46 public:
  47     enum RxStatus {
  48         NoData,
  49         MasterGeneralCall,
  50         MasterWrite,
  51         MasterRead
  52     };
  53
  54     enum Acknowledge {
  55         NoACK = 0,
  56         ACK   = 1
  57     };
  58
  59     /** Create an I2C Master interface, connected to the specified pins
  60      *
  61      *  @param sda I2C data line pin
  62      *  @param scl I2C clock line pin
  63      */
  64     I2C(PinName sda, PinName scl);
  65
  66     /** Set the frequency of the I2C interface
  67      *
  68      *  @param hz The bus frequency in hertz
  69      */
  70     void frequency(int hz);
  71
  72     /** Read from an I2C slave
  73      *
  74      * Performs a complete read transaction. The bottom bit of
  75      * the address is forced to 1 to indicate a read.
  76      *
  77      *  @param address 8-bit I2C slave address [ addr | 1 ]
  78      *  @param data Pointer to the byte-array to read data in to
  79      *  @param length Number of bytes to read
  80      *  @param repeated Repeated start, true - don't send stop at end
  81      *
  82      *  @returns
  83      *       0 on success (ack),
  84      *   non-0 on failure (nack)
  85      */
  86     int read(int address, char *data, int length, bool repeated = false);
  87
  88     /** Read a single byte from the I2C bus
  89      *
  90      *  @param ack indicates if the byte is to be acknowledged (1 = acknowledge)
  91      *
  92      *  @returns
  93      *    the byte read
  94      */
  95     int read(int ack);
  96
  97     /** Write to an I2C slave
  98      *
  99      * Performs a complete write transaction. The bottom bit of
 100      * the address is forced to 0 to indicate a write.
 101      *
 102      *  @param address 8-bit I2C slave address [ addr | 0 ]
 103      *  @param data Pointer to the byte-array data to send
 104      *  @param length Number of bytes to send
 105      *  @param repeated Repeated start, true - do not send stop at end
 106      *
 107      *  @returns
 108      *       0 on success (ack),
 109      *   non-0 on failure (nack)
 110      */
 111     int write(int address, const char *data, int length, bool repeated = false);
 112
 113     /** Write single byte out on the I2C bus
 114      *
 115      *  @param data data to write out on bus
 116      *
 117      *  @returns
 118      *    '1' if an ACK was received,
 119      *    '0' otherwise
 120      */
 121     int write(int data);
 122
 123     /** Creates a start condition on the I2C bus
 124      */
 125
 126     void start(void);
 127
 128     /** Creates a stop condition on the I2C bus
 129      */
 130     void stop(void);
 131
 132 protected:
 133     void aquire();
 134
 135     i2c_t _i2c;
 136     static I2C  *_owner;
 137     int         _hz;
 138 };
 139
 140 } // namespace mbed
 141
 142 #endif
 143
 144 #endif