tmk_core/tool/mbed/mbed-sdk/libraries/mbed/api/SPISlave.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_SPISLAVE_H
  17 #define MBED_SPISLAVE_H
  18
  19 #include "platform.h"
  20
  21 #if DEVICE_SPISLAVE
  22
  23 #include "spi_api.h"
  24
  25 namespace mbed {
  26
  27 /** A SPI slave, used for communicating with a SPI Master device
  28  *
  29  * The default format is set to 8-bits, mode 0, and a clock frequency of 1MHz
  30  *
  31  * Example:
  32  * @code
  33  * // Reply to a SPI master as slave
  34  *
  35  * #include "mbed.h"
  36  *
  37  * SPISlave device(p5, p6, p7, p8); // mosi, miso, sclk, ssel
  38  *
  39  * int main() {
  40  *     device.reply(0x00);              // Prime SPI with first reply
  41  *     while(1) {
  42  *         if(device.receive()) {
  43  *             int v = device.read();   // Read byte from master
  44  *             v = (v + 1) % 0x100;     // Add one to it, modulo 256
  45  *             device.reply(v);         // Make this the next reply
  46  *         }
  47  *     }
  48  * }
  49  * @endcode
  50  */
  51 class SPISlave {
  52
  53 public:
  54
  55     /** Create a SPI slave connected to the specified pins
  56      *
  57      * Pin Options:
  58      *  (5, 6, 7i, 8) or (11, 12, 13, 14)
  59      *
  60      *  mosi or miso can be specfied as NC if not used
  61      *
  62      *  @param mosi SPI Master Out, Slave In pin
  63      *  @param miso SPI Master In, Slave Out pin
  64      *  @param sclk SPI Clock pin
  65      *  @param ssel SPI chip select pin
  66      *  @param name (optional) A string to identify the object
  67      */
  68     SPISlave(PinName mosi, PinName miso, PinName sclk, PinName ssel);
  69
  70     /** Configure the data transmission format
  71      *
  72      *  @param bits Number of bits per SPI frame (4 - 16)
  73      *  @param mode Clock polarity and phase mode (0 - 3)
  74      *
  75      * @code
  76      * mode | POL PHA
  77      * -----+--------
  78      *   0  |  0   0
  79      *   1  |  0   1
  80      *   2  |  1   0
  81      *   3  |  1   1
  82      * @endcode
  83      */
  84     void format(int bits, int mode = 0);
  85
  86     /** Set the spi bus clock frequency
  87      *
  88      *  @param hz SCLK frequency in hz (default = 1MHz)
  89      */
  90     void frequency(int hz = 1000000);
  91
  92     /** Polls the SPI to see if data has been received
  93      *
  94      *  @returns
  95      *    0 if no data,
  96      *    1 otherwise
  97      */
  98     int receive(void);
  99
 100     /** Retrieve  data from receive buffer as slave
 101      *
 102      *  @returns
 103      *    the data in the receive buffer
 104      */
 105     int read(void);
 106
 107     /** Fill the transmission buffer with the value to be written out
 108      *  as slave on the next received message from the master.
 109      *
 110      *  @param value the data to be transmitted next
 111      */
 112     void reply(int value);
 113
 114 protected:
 115     spi_t _spi;
 116
 117     int _bits;
 118     int _mode;
 119     int _hz;
 120 };
 121
 122 } // namespace mbed
 123
 124 #endif
 125
 126 #endif