tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_Freescale/TARGET_KLXX/rtc_api.c

   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 "rtc_api.h"
  17 #include "PeripheralPins.h"
  18
  19 static void init(void) {
  20     // enable RTC clock
  21     SIM->SCGC6 |= SIM_SCGC6_RTC_MASK;
  22
  23     pinmap_pinout(PinMap_RTC[0].pin, PinMap_RTC);        //Map RTC clk input (if not NC)
  24
  25     // select RTC clock source
  26     SIM->SOPT1 &= ~SIM_SOPT1_OSC32KSEL_MASK;
  27     SIM->SOPT1 |= SIM_SOPT1_OSC32KSEL(PinMap_RTC[0].peripheral);
  28 }
  29
  30 void rtc_init(void) {
  31     init();
  32
  33     //Configure the TSR. default value: 1
  34     RTC->TSR = 1;
  35
  36     if (PinMap_RTC[0].pin == NC) {        //Use OSC32K
  37         RTC->CR |= RTC_CR_OSCE_MASK;
  38         //delay for OSCE stabilization
  39         for(int i=0; i<0x1000; i++) __NOP();
  40     }
  41
  42     // enable counter
  43     RTC->SR |= RTC_SR_TCE_MASK;
  44 }
  45
  46 void rtc_free(void) {
  47     // [TODO]
  48 }
  49
  50 /*
  51  * Little check routine to see if the RTC has been enabled
  52  * 0 = Disabled, 1 = Enabled
  53  */
  54 int rtc_isenabled(void) {
  55     // even if the RTC module is enabled,
  56     // as we use RTC_CLKIN and an external clock,
  57     // we need to reconfigure the pins. That is why we
  58     // call init() if the rtc is enabled
  59
  60     // if RTC not enabled return 0
  61     SIM->SCGC5 |= SIM_SCGC5_PORTA_MASK;
  62     SIM->SCGC6 |= SIM_SCGC6_RTC_MASK;
  63     if ((RTC->SR & RTC_SR_TCE_MASK) == 0)
  64         return 0;
  65
  66     init();
  67     return 1;
  68 }
  69
  70 time_t rtc_read(void) {
  71     return RTC->TSR;
  72 }
  73
  74 void rtc_write(time_t t) {
  75     // disable counter
  76     RTC->SR &= ~RTC_SR_TCE_MASK;
  77
  78     // we do not write 0 into TSR
  79     // to avoid invalid time
  80     if (t == 0)
  81         t = 1;
  82
  83     // write seconds
  84     RTC->TSR = t;
  85
  86     // re-enable counter
  87     RTC->SR |= RTC_SR_TCE_MASK;
  88 }