tmk_core/tool/mbed/mbed-sdk/libraries/mbed/common/SPI.cpp

   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 #include "SPI.h"
  17
  18 #if DEVICE_SPI
  19
  20 namespace mbed {
  21
  22 SPI::SPI(PinName mosi, PinName miso, PinName sclk, PinName _unused) :
  23         _spi(),
  24         _bits(8),
  25         _mode(0),
  26         _hz(1000000) {
  27     spi_init(&_spi, mosi, miso, sclk, NC);
  28     spi_format(&_spi, _bits, _mode, 0);
  29     spi_frequency(&_spi, _hz);
  30 }
  31
  32 void SPI::format(int bits, int mode) {
  33     _bits = bits;
  34     _mode = mode;
  35     SPI::_owner = NULL; // Not that elegant, but works. rmeyer
  36     aquire();
  37 }
  38
  39 void SPI::frequency(int hz) {
  40     _hz = hz;
  41     SPI::_owner = NULL; // Not that elegant, but works. rmeyer
  42     aquire();
  43 }
  44
  45 SPI* SPI::_owner = NULL;
  46
  47 // ignore the fact there are multiple physical spis, and always update if it wasnt us last
  48 void SPI::aquire() {
  49      if (_owner != this) {
  50         spi_format(&_spi, _bits, _mode, 0);
  51         spi_frequency(&_spi, _hz);
  52         _owner = this;
  53     }
  54 }
  55
  56 int SPI::write(int value) {
  57     aquire();
  58     return spi_master_write(&_spi, value);
  59 }
  60
  61 } // namespace mbed
  62
  63 #endif