1 /* mbed Microcontroller Library
2 * Copyright (c) 2006-2013 ARM Limited
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
18 // ensure rtc is running (unchanged if already running)
20 /* Setup the RTC based on a time structure, ensuring RTC is enabled
22 * Can be clocked by a 32.768KHz oscillator or prescale divider based on the APB clock
23 * - We want to use the 32khz clock, allowing for sleep mode
25 * Most registers are not changed by a Reset
26 * - We must initialize these registers between power-on and setting the RTC into operation
28 * Clock Control Register
29 * RTC_CCR[0] : Enable - 0 = Disabled, 1 = Enabled
30 * RTC_CCR[1] : Reset - 0 = Normal, 1 = Reset
32 * The RTC may already be running, so we should set it up
33 * without impacting if it is the case
36 LPC_SC->PCONP |= 0x200; // Ensure power is on
39 LPC_RTC->CCR |= 1 << 0; // Ensure the RTC is enabled
47 * Little check routine to see if the RTC has been enabled
49 * Clock Control Register
50 * RTC_CCR[0] : 0 = Disabled, 1 = Enabled
53 int rtc_isenabled(void) {
54 return(((LPC_RTC->CCR) & 0x01) != 0);
59 * RTC_SEC Seconds 0-59
60 * RTC_MIN Minutes 0-59
62 * RTC_DOM Day of Month 1-28..31
63 * RTC_DOW Day of Week 0-6
64 * RTC_DOY Day of Year 1-365
65 * RTC_MONTH Month 1-12
66 * RTC_YEAR Year 0-4095
69 * tm_sec seconds after the minute 0-61
70 * tm_min minutes after the hour 0-59
71 * tm_hour hours since midnight 0-23
72 * tm_mday day of the month 1-31
73 * tm_mon months since January 0-11
74 * tm_year years since 1900
75 * tm_wday days since Sunday 0-6
76 * tm_yday days since January 1 0-365
77 * tm_isdst Daylight Saving Time flag
79 time_t rtc_read(void) {
80 // Setup a tm structure based on the RTC
82 timeinfo.tm_sec = LPC_RTC->SEC;
83 timeinfo.tm_min = LPC_RTC->MIN;
84 timeinfo.tm_hour = LPC_RTC->HOUR;
85 timeinfo.tm_mday = LPC_RTC->DOM;
86 timeinfo.tm_mon = LPC_RTC->MONTH - 1;
87 timeinfo.tm_year = LPC_RTC->YEAR - 1900;
89 // Convert to timestamp
90 time_t t = mktime(&timeinfo);
95 void rtc_write(time_t t) {
96 // Convert the time in to a tm
97 struct tm *timeinfo = localtime(&t);
99 // Pause clock, and clear counter register (clears us count)
103 LPC_RTC->SEC = timeinfo->tm_sec;
104 LPC_RTC->MIN = timeinfo->tm_min;
105 LPC_RTC->HOUR = timeinfo->tm_hour;
106 LPC_RTC->DOM = timeinfo->tm_mday;
107 LPC_RTC->MONTH = timeinfo->tm_mon + 1;
108 LPC_RTC->YEAR = timeinfo->tm_year + 1900;
111 LPC_RTC->CCR &= ~((uint32_t)2);