tmk_core/tool/mbed/mbed-sdk/libraries/mbed/api/SPI.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_SPI_H
  17 #define MBED_SPI_H
  18
  19 #include "platform.h"
  20
  21 #if DEVICE_SPI
  22
  23 #include "spi_api.h"
  24
  25 namespace mbed {
  26
  27 /** A SPI Master, used for communicating with SPI slave devices
  28  *
  29  * The default format is set to 8-bits, mode 0, and a clock frequency of 1MHz
  30  *
  31  * Most SPI devices will also require Chip Select and Reset signals. These
  32  * can be controlled using <DigitalOut> pins
  33  *
  34  * Example:
  35  * @code
  36  * // Send a byte to a SPI slave, and record the response
  37  *
  38  * #include "mbed.h"
  39  *
  40  * SPI device(p5, p6, p7); // mosi, miso, sclk
  41  *
  42  * int main() {
  43  *     int response = device.write(0xFF);
  44  * }
  45  * @endcode
  46  */
  47 class SPI {
  48
  49 public:
  50
  51     /** Create a SPI master connected to the specified pins
  52      *
  53      * Pin Options:
  54      *  (5, 6, 7) or (11, 12, 13)
  55      *
  56      *  mosi or miso can be specfied as NC if not used
  57      *
  58      *  @param mosi SPI Master Out, Slave In pin
  59      *  @param miso SPI Master In, Slave Out pin
  60      *  @param sclk SPI Clock pin
  61      */
  62     SPI(PinName mosi, PinName miso, PinName sclk, PinName _unused=NC);
  63
  64     /** Configure the data transmission format
  65      *
  66      *  @param bits Number of bits per SPI frame (4 - 16)
  67      *  @param mode Clock polarity and phase mode (0 - 3)
  68      *
  69      * @code
  70      * mode | POL PHA
  71      * -----+--------
  72      *   0  |  0   0
  73      *   1  |  0   1
  74      *   2  |  1   0
  75      *   3  |  1   1
  76      * @endcode
  77      */
  78     void format(int bits, int mode = 0);
  79
  80     /** Set the spi bus clock frequency
  81      *
  82      *  @param hz SCLK frequency in hz (default = 1MHz)
  83      */
  84     void frequency(int hz = 1000000);
  85
  86     /** Write to the SPI Slave and return the response
  87      *
  88      *  @param value Data to be sent to the SPI slave
  89      *
  90      *  @returns
  91      *    Response from the SPI slave
  92     */
  93     virtual int write(int value);
  94
  95 public:
  96     virtual ~SPI() {
  97     }
  98
  99 protected:
 100     spi_t _spi;
 101
 102     void aquire(void);
 103     static SPI *_owner;
 104     int _bits;
 105     int _mode;
 106     int _hz;
 107 };
 108
 109 } // namespace mbed
 110
 111 #endif
 112
 113 #endif