tmk_core/tool/mbed/mbed-sdk/libraries/mbed/api/I2CSlave.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_SLAVE_H
  17 #define MBED_I2C_SLAVE_H
  18
  19 #include "platform.h"
  20
  21 #if DEVICE_I2CSLAVE
  22
  23 #include "i2c_api.h"
  24
  25 namespace mbed {
  26
  27 /** An I2C Slave, used for communicating with an I2C Master device
  28  *
  29  * Example:
  30  * @code
  31  * // Simple I2C responder
  32  * #include <mbed.h>
  33  *
  34  * I2CSlave slave(p9, p10);
  35  *
  36  * int main() {
  37  *     char buf[10];
  38  *     char msg[] = "Slave!";
  39  *
  40  *     slave.address(0xA0);
  41  *     while (1) {
  42  *         int i = slave.receive();
  43  *         switch (i) {
  44  *             case I2CSlave::ReadAddressed:
  45  *                 slave.write(msg, strlen(msg) + 1); // Includes null char
  46  *                 break;
  47  *             case I2CSlave::WriteGeneral:
  48  *                 slave.read(buf, 10);
  49  *                 printf("Read G: %s\n", buf);
  50  *                 break;
  51  *             case I2CSlave::WriteAddressed:
  52  *                 slave.read(buf, 10);
  53  *                 printf("Read A: %s\n", buf);
  54  *                 break;
  55  *         }
  56  *         for(int i = 0; i < 10; i++) buf[i] = 0;    // Clear buffer
  57  *     }
  58  * }
  59  * @endcode
  60  */
  61 class I2CSlave {
  62
  63 public:
  64     enum RxStatus {
  65         NoData         = 0,
  66         ReadAddressed  = 1,
  67         WriteGeneral   = 2,
  68         WriteAddressed = 3
  69     };
  70
  71     /** Create an I2C Slave interface, connected to the specified pins.
  72      *
  73      *  @param sda I2C data line pin
  74      *  @param scl I2C clock line pin
  75      */
  76     I2CSlave(PinName sda, PinName scl);
  77
  78     /** Set the frequency of the I2C interface
  79      *
  80      *  @param hz The bus frequency in hertz
  81      */
  82     void frequency(int hz);
  83
  84     /** Checks to see if this I2C Slave has been addressed.
  85      *
  86      *  @returns
  87      *  A status indicating if the device has been addressed, and how
  88      *  - NoData            - the slave has not been addressed
  89      *  - ReadAddressed     - the master has requested a read from this slave
  90      *  - WriteAddressed    - the master is writing to this slave
  91      *  - WriteGeneral      - the master is writing to all slave
  92      */
  93     int receive(void);
  94
  95     /** Read from an I2C master.
  96      *
  97      *  @param data pointer to the byte array to read data in to
  98      *  @param length maximum number of bytes to read
  99      *
 100      *  @returns
 101      *       0 on success,
 102      *   non-0 otherwise
 103      */
 104     int read(char *data, int length);
 105
 106     /** Read a single byte from an I2C master.
 107      *
 108      *  @returns
 109      *    the byte read
 110      */
 111     int read(void);
 112
 113     /** Write to an I2C master.
 114      *
 115      *  @param data pointer to the byte array to be transmitted
 116      *  @param length the number of bytes to transmite
 117      *
 118      *  @returns
 119      *       0 on success,
 120      *   non-0 otherwise
 121      */
 122     int write(const char *data, int length);
 123
 124     /** Write a single byte to an I2C master.
 125      *
 126      *  @data the byte to write
 127      *
 128      *  @returns
 129      *    '1' if an ACK was received,
 130      *    '0' otherwise
 131      */
 132     int write(int data);
 133
 134     /** Sets the I2C slave address.
 135      *
 136      *  @param address The address to set for the slave (ignoring the least
 137      *  signifcant bit). If set to 0, the slave will only respond to the
 138      *  general call address.
 139      */
 140     void address(int address);
 141
 142     /** Reset the I2C slave back into the known ready receiving state.
 143      */
 144     void stop(void);
 145
 146 protected:
 147     i2c_t _i2c;
 148 };
 149
 150 } // namespace mbed
 151
 152 #endif
 153
 154 #endif