text: // Copyright (c) 2016, Joe Krachey
  // All rights reserved.
  //
  // Redistribution and use in binary form, with or without modification, 
  // are permitted provided that the following conditions are met:
  //
  // 1. Redistributions in binary form must reproduce the above copyright 
  //    notice, this list of conditions and the following disclaimer in 
  //    the documentation and/or other materials provided with the distribution.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
  // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 
  // THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
  // PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 
  // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
  // EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 
  // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 
  // OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
  // WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 
  // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 
  // EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  #ifndef __SPI_SELECT_H__
  #define __SPI_SELECT_H__
  #include <stdint.h>
  #include <stdbool.h>
  #include "gpio_port.h"
  
  typedef enum {
    NORDIC    = 0,
    SD_CARD   = 1,
    MODULE_0  = 2,
    MODULE_1  = 3
  } spi_device_t;
  
  #define   SPI_SELECT_0_GPIO_BASE  GPIOD_BASE
  #define   SPI_SELECT_0_PIN        PD0
  #define   SPI_SELECT_0_PORT       GPIOD
  
  #define   SPI_SELECT_1_GPIO_BASE  GPIOD_BASE
  #define   SPI_SELECT_1_PIN        PD1
  #define   SPI_SELECT_1_PORT       GPIOD
  
  //*****************************************************************************
  // Initialize the Pins used to determine which SPI device is active
  //*****************************************************************************
  bool  spi_select_init(void);
  
  //*****************************************************************************
  // Selects the currently active SPI device
  //*****************************************************************************
  void  spi_select(spi_device_t device);
  
  #endif
  