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.
20 // ensure rtc is running (unchanged if already running)
22 /* Setup the RTC based on a time structure, ensuring RTC is enabled
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
27 * Most registers are not changed by a Reset
28 * - We must initialize these registers between power-on and setting the RTC into operation
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
35 * The RTC may already be running, so we should set it up
36 * without impacting if it is the case
39 LPC_SC
->PCONP
|= 0x200; // Ensure power is on
42 // clock source on 2368 is special test mode on 1768!
44 LPC_RTC
->CCR
|= 1 << 4; // Ensure clock source is 32KHz Xtal
47 LPC_RTC
->CCR
|= 1 << 0; // Ensure the RTC is enabled
55 * Little check routine to see if the RTC has been enabled
57 * Clock Control Register
58 * RTC_CCR[0] : 0 = Disabled, 1 = Enabled
62 int rtc_isenabled(void) {
63 return(((LPC_RTC
->CCR
) & 0x01) != 0);
68 * RTC_SEC Seconds 0-59
69 * RTC_MIN Minutes 0-59
71 * RTC_DOM Day of Month 1-28..31
72 * RTC_DOW Day of Week 0-6
73 * RTC_DOY Day of Year 1-365
74 * RTC_MONTH Month 1-12
75 * RTC_YEAR Year 0-4095
78 * tm_sec seconds after the minute 0-61
79 * tm_min minutes after the hour 0-59
80 * tm_hour hours since midnight 0-23
81 * tm_mday day of the month 1-31
82 * tm_mon months since January 0-11
83 * tm_year years since 1900
84 * tm_wday days since Sunday 0-6
85 * tm_yday days since January 1 0-365
86 * tm_isdst Daylight Saving Time flag
88 time_t rtc_read(void) {
89 // Setup a tm structure based on the RTC
91 timeinfo
.tm_sec
= LPC_RTC
->SEC
;
92 timeinfo
.tm_min
= LPC_RTC
->MIN
;
93 timeinfo
.tm_hour
= LPC_RTC
->HOUR
;
94 timeinfo
.tm_mday
= LPC_RTC
->DOM
;
95 timeinfo
.tm_mon
= LPC_RTC
->MONTH
- 1;
96 timeinfo
.tm_year
= LPC_RTC
->YEAR
- 1900;
98 // Convert to timestamp
99 time_t t
= mktime(&timeinfo
);
104 void rtc_write(time_t t
) {
105 // Convert the time in to a tm
106 struct tm
*timeinfo
= localtime(&t
);
108 // Pause clock, and clear counter register (clears us count)
112 LPC_RTC
->SEC
= timeinfo
->tm_sec
;
113 LPC_RTC
->MIN
= timeinfo
->tm_min
;
114 LPC_RTC
->HOUR
= timeinfo
->tm_hour
;
115 LPC_RTC
->DOM
= timeinfo
->tm_mday
;
116 LPC_RTC
->MONTH
= timeinfo
->tm_mon
+ 1;
117 LPC_RTC
->YEAR
= timeinfo
->tm_year
+ 1900;
120 LPC_RTC
->CCR
&= ~((uint32_t)2);