text: /* mbed Microcontroller Library
   * Copyright (c) 2006-2013 ARM Limited
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  #include "gpio_api.h"
  
  #define CRC16
  #include "crc.h"
  #include "fsl_rtc.h"
  #include "fsl_clock_config.h"
  
  // called before main
  void mbed_sdk_init()
  {
      rtc_config_t rtc_basic_config;
      uint32_t u32cTPR_counter = 0;
  
      BOARD_BootClockRUN();
  
      CLOCK_EnableClock(kCLOCK_Rtc0);
  
      /* Check if the Rtc oscillator is enabled */
      if ((RTC->CR & RTC_CR_OSCE_MASK) == 0u) {
          /*Init the RTC with default configuration*/
          RTC_GetDefaultConfig(&rtc_basic_config);
  
          /* Setup the 32K RTC OSC */
          RTC_Init(RTC, &rtc_basic_config);
  
          /* Enable the RTC 32KHz oscillator */
          RTC->CR |= RTC_CR_OSCE_MASK;
  
          /* Start the RTC time counter */
          RTC_StartTimer(RTC);
  
          /* Verify TPR register reaches 4096 counts */
          while (u32cTPR_counter < 4096) {
              u32cTPR_counter = RTC->TPR;
          }
          /* 32kHz Oscillator is ready. */
          RTC_Deinit(RTC);
      }
  
      CLOCK_DisableClock(kCLOCK_Rtc0);
  }
  
  // Change the NMI pin to an input. This allows NMI pin to
  //  be used as a low power mode wakeup.  The application will
  //  need to change the pin back to NMI_b or wakeup only occurs once!
  void NMI_Handler(void)
  {
      gpio_t gpio;
      gpio_init_in(&gpio, PTA4);
  }
  
  // Provide ethernet devices with a semi-unique MAC address from the UUID
  void mbed_mac_address(char *mac)
  {
      uint16_t MAC[3];                        // 3 16 bits words for the MAC
  
      // get UID via SIM_UID macros defined in the K64F MCU CMSIS header file
      uint32_t UID[4];
      UID[0] = SIM->UIDH;
      UID[1] = SIM->UIDMH;
      UID[2] = SIM->UIDML;
      UID[3] = SIM->UIDL;
  
      // generate three CRC16's using different slices of the UUID
      MAC[0] = crcSlow((const uint8_t *)UID, 8);  // most significant half-word
      MAC[1] = crcSlow((const uint8_t *)UID, 12);
      MAC[2] = crcSlow((const uint8_t *)UID, 16); // least significant half word
  
      // The network stack expects an array of 6 bytes
      // so we copy, and shift and copy from the half-word array to the byte array
      mac[0] = MAC[0] >> 8;
      mac[1] = MAC[0];
      mac[2] = MAC[1] >> 8;
      mac[3] = MAC[1];
      mac[4] = MAC[2] >> 8;
      mac[5] = MAC[2];
  
      // We want to force bits [1:0] of the most significant byte [0]
      // to be "10"
      // http://en.wikipedia.org/wiki/MAC_address
  
      mac[0] |= 0x02; // force bit 1 to a "1" = "Locally Administered"
      mac[0] &= 0xFE; // force bit 0 to a "0" = Unicast
  
  }
  
  
  
  