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
31 * RTC_CCR[4] : Clock Source - 0 = Prescaler, 1 = 32k Xtal
33 * The RTC may already be running, so we should set it up
34 * without impacting if it is the case
37 LPC_SC->PCONP |= 0x200; // Ensure power is on
40 // clock source on 2368 is special test mode on 1768!
41 LPC_RTC->CCR |= 1 << 4; // Ensure clock source is 32KHz Xtal
43 LPC_RTC->CCR |= 1 << 0; // Ensure the RTC is enabled
51 * Little check routine to see if the RTC has been enabled
53 * Clock Control Register
54 * RTC_CCR[0] : 0 = Disabled, 1 = Enabled
58 int rtc_isenabled(void) {
59 return(((LPC_RTC->CCR) & 0x01) != 0);
64 * RTC_SEC Seconds 0-59
65 * RTC_MIN Minutes 0-59
67 * RTC_DOM Day of Month 1-28..31
68 * RTC_DOW Day of Week 0-6
69 * RTC_DOY Day of Year 1-365
70 * RTC_MONTH Month 1-12
71 * RTC_YEAR Year 0-4095
74 * tm_sec seconds after the minute 0-61
75 * tm_min minutes after the hour 0-59
76 * tm_hour hours since midnight 0-23
77 * tm_mday day of the month 1-31
78 * tm_mon months since January 0-11
79 * tm_year years since 1900
80 * tm_wday days since Sunday 0-6
81 * tm_yday days since January 1 0-365
82 * tm_isdst Daylight Saving Time flag
84 time_t rtc_read(void) {
85 // Setup a tm structure based on the RTC
87 timeinfo.tm_sec = LPC_RTC->SEC;
88 timeinfo.tm_min = LPC_RTC->MIN;
89 timeinfo.tm_hour = LPC_RTC->HOUR;
90 timeinfo.tm_mday = LPC_RTC->DOM;
91 timeinfo.tm_mon = LPC_RTC->MONTH - 1;
92 timeinfo.tm_year = LPC_RTC->YEAR - 1900;
94 // Convert to timestamp
95 time_t t = mktime(&timeinfo);
100 void rtc_write(time_t t) {
101 // Convert the time in to a tm
102 struct tm *timeinfo = localtime(&t);
104 // Pause clock, and clear counter register (clears us count)
108 LPC_RTC->SEC = timeinfo->tm_sec;
109 LPC_RTC->MIN = timeinfo->tm_min;
110 LPC_RTC->HOUR = timeinfo->tm_hour;
111 LPC_RTC->DOM = timeinfo->tm_mday;
112 LPC_RTC->MONTH = timeinfo->tm_mon + 1;
113 LPC_RTC->YEAR = timeinfo->tm_year + 1900;
116 LPC_RTC->CCR &= ~((uint32_t)2);