tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC43XX/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  * Ported to NXP LPC43XX by Micromint USA <support@micromint.com>
  17  */
  18 #include "rtc_api.h"
  19
  20 // ensure rtc is running (unchanged if already running)
  21
  22 /* Setup the RTC based on a time structure, ensuring RTC is enabled
  23  *
  24  * Can be clocked by a 32.768KHz oscillator or prescale divider based on the APB clock
  25  * - We want to use the 32khz clock, allowing for sleep mode
  26  *
  27  * Most registers are not changed by a Reset
  28  * - We must initialize these registers between power-on and setting the RTC into operation
  29
  30  * Clock Control Register
  31  *  RTC_CCR[0] : Enable - 0 = Disabled, 1 = Enabled
  32  *  RTC_CCR[1] : Reset - 0 = Normal, 1 = Reset
  33  *  RTC_CCR[4] : Clock Source - 0 = Prescaler, 1 = 32k Xtal
  34  *
  35  * The RTC may already be running, so we should set it up
  36  * without impacting if it is the case
  37  */
  38
  39 void rtc_init(void) {
  40     // Return, if already enabled
  41     if (LPC_RTC->CCR & 1)
  42         return;
  43
  44     // Enable 1kHz output of 32kHz oscillator
  45     LPC_CREG->CREG0 &= ~((1 << 3) | (1 << 2));
  46     LPC_CREG->CREG0 |= (0x03 << 6) | (1 << 1) | (1 << 0);
  47
  48     // Enable RTC
  49     do {
  50         LPC_RTC->CCR |= 1 << 0;
  51     } while ((LPC_RTC->CCR & 1) == 0);
  52 }
  53
  54 void rtc_free(void) {
  55     // [TODO]
  56 }
  57
  58 /*
  59  * Little check routine to see if the RTC has been enabled
  60  *
  61  * Clock Control Register
  62  *  RTC_CCR[0] : 0 = Disabled, 1 = Enabled
  63  *
  64  */
  65 int rtc_isenabled(void) {
  66     return(((LPC_RTC->CCR) & 0x01) != 0);
  67 }
  68
  69 /*
  70  * RTC Registers
  71  *  RTC_SEC        Seconds 0-59
  72  *  RTC_MIN        Minutes 0-59
  73  *  RTC_HOUR    Hour 0-23
  74  *  RTC_DOM        Day of Month 1-28..31
  75  *  RTC_DOW        Day of Week 0-6
  76  *  RTC_DOY        Day of Year 1-365
  77  *  RTC_MONTH    Month 1-12
  78  *  RTC_YEAR    Year 0-4095
  79  *
  80  * struct tm
  81  *  tm_sec        seconds after the minute 0-61
  82  *  tm_min        minutes after the hour 0-59
  83  *  tm_hour        hours since midnight 0-23
  84  *  tm_mday        day of the month 1-31
  85  *  tm_mon        months since January 0-11
  86  *  tm_year        years since 1900
  87  *  tm_wday        days since Sunday 0-6
  88  *  tm_yday        days since January 1 0-365
  89  *  tm_isdst    Daylight Saving Time flag
  90  */
  91 time_t rtc_read(void) {
  92     // Setup a tm structure based on the RTC
  93     struct tm timeinfo;
  94     timeinfo.tm_sec = LPC_RTC->TIME[RTC_TIMETYPE_SECOND];
  95     timeinfo.tm_min = LPC_RTC->TIME[RTC_TIMETYPE_MINUTE];
  96     timeinfo.tm_hour = LPC_RTC->TIME[RTC_TIMETYPE_HOUR];
  97     timeinfo.tm_mday = LPC_RTC->TIME[RTC_TIMETYPE_DAYOFMONTH];
  98     timeinfo.tm_wday = LPC_RTC->TIME[RTC_TIMETYPE_DAYOFWEEK];
  99     timeinfo.tm_yday = LPC_RTC->TIME[RTC_TIMETYPE_DAYOFYEAR];
 100     timeinfo.tm_mon = LPC_RTC->TIME[RTC_TIMETYPE_MONTH] - 1;
 101     timeinfo.tm_year = LPC_RTC->TIME[RTC_TIMETYPE_YEAR] - 1900;
 102
 103     // Convert to timestamp
 104     time_t t = mktime(&timeinfo);
 105
 106     return t;
 107 }
 108
 109 void rtc_write(time_t t) {
 110     // Convert the time in to a tm
 111     struct tm *timeinfo = localtime(&t);
 112
 113     // Pause clock, and clear counter register (clears us count)
 114     LPC_RTC->CCR |= 2;
 115
 116     // Set the RTC
 117     LPC_RTC->TIME[RTC_TIMETYPE_SECOND] = timeinfo->tm_sec;
 118     LPC_RTC->TIME[RTC_TIMETYPE_MINUTE] = timeinfo->tm_min;
 119     LPC_RTC->TIME[RTC_TIMETYPE_HOUR] = timeinfo->tm_hour;
 120     LPC_RTC->TIME[RTC_TIMETYPE_DAYOFMONTH] = timeinfo->tm_mday;
 121     LPC_RTC->TIME[RTC_TIMETYPE_DAYOFWEEK] = timeinfo->tm_wday;
 122     LPC_RTC->TIME[RTC_TIMETYPE_DAYOFYEAR] = timeinfo->tm_yday;
 123     LPC_RTC->TIME[RTC_TIMETYPE_MONTH] = timeinfo->tm_mon + 1;
 124     LPC_RTC->TIME[RTC_TIMETYPE_YEAR] = timeinfo->tm_year + 1900;
 125
 126     // Restart clock
 127     LPC_RTC->CCR &= ~((uint32_t)2);
 128 }