mbed-os/targets/TARGET_NXP/TARGET_LPC43XX/rtc_api.c

129 lines
4.1 KiB
C

/* mbed Microcontroller Library
* Copyright (c) 2006-2013 ARM Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Ported to NXP LPC43XX by Micromint USA <support@micromint.com>
*/
#include "rtc_api.h"
// ensure rtc is running (unchanged if already running)
/* Setup the RTC based on a time structure, ensuring RTC is enabled
*
* Can be clocked by a 32.768KHz oscillator or prescale divider based on the APB clock
* - We want to use the 32khz clock, allowing for sleep mode
*
* Most registers are not changed by a Reset
* - We must initialize these registers between power-on and setting the RTC into operation
* Clock Control Register
* RTC_CCR[0] : Enable - 0 = Disabled, 1 = Enabled
* RTC_CCR[1] : Reset - 0 = Normal, 1 = Reset
* RTC_CCR[4] : Clock Source - 0 = Prescaler, 1 = 32k Xtal
*
* The RTC may already be running, so we should set it up
* without impacting if it is the case
*/
void rtc_init(void) {
// Return, if already enabled
if (LPC_RTC->CCR & 1)
return;
// Enable 1kHz output of 32kHz oscillator
LPC_CREG->CREG0 &= ~((1 << 3) | (1 << 2));
LPC_CREG->CREG0 |= (0x03 << 6) | (1 << 1) | (1 << 0);
// Enable RTC
do {
LPC_RTC->CCR |= 1 << 0;
} while ((LPC_RTC->CCR & 1) == 0);
}
void rtc_free(void) {
// [TODO]
}
/*
* Little check routine to see if the RTC has been enabled
*
* Clock Control Register
* RTC_CCR[0] : 0 = Disabled, 1 = Enabled
*
*/
int rtc_isenabled(void) {
return(((LPC_RTC->CCR) & 0x01) != 0);
}
/*
* RTC Registers
* RTC_SEC Seconds 0-59
* RTC_MIN Minutes 0-59
* RTC_HOUR Hour 0-23
* RTC_DOM Day of Month 1-28..31
* RTC_DOW Day of Week 0-6
* RTC_DOY Day of Year 1-365
* RTC_MONTH Month 1-12
* RTC_YEAR Year 0-4095
*
* struct tm
* tm_sec seconds after the minute 0-61
* tm_min minutes after the hour 0-59
* tm_hour hours since midnight 0-23
* tm_mday day of the month 1-31
* tm_mon months since January 0-11
* tm_year years since 1900
* tm_wday days since Sunday 0-6
* tm_yday days since January 1 0-365
* tm_isdst Daylight Saving Time flag
*/
time_t rtc_read(void) {
// Setup a tm structure based on the RTC
struct tm timeinfo;
timeinfo.tm_sec = LPC_RTC->TIME[RTC_TIMETYPE_SECOND];
timeinfo.tm_min = LPC_RTC->TIME[RTC_TIMETYPE_MINUTE];
timeinfo.tm_hour = LPC_RTC->TIME[RTC_TIMETYPE_HOUR];
timeinfo.tm_mday = LPC_RTC->TIME[RTC_TIMETYPE_DAYOFMONTH];
timeinfo.tm_wday = LPC_RTC->TIME[RTC_TIMETYPE_DAYOFWEEK];
timeinfo.tm_yday = LPC_RTC->TIME[RTC_TIMETYPE_DAYOFYEAR];
timeinfo.tm_mon = LPC_RTC->TIME[RTC_TIMETYPE_MONTH] - 1;
timeinfo.tm_year = LPC_RTC->TIME[RTC_TIMETYPE_YEAR] - 1900;
// Convert to timestamp
time_t t = mktime(&timeinfo);
return t;
}
void rtc_write(time_t t) {
// Convert the time in to a tm
struct tm *timeinfo = localtime(&t);
// Pause clock, and clear counter register (clears us count)
LPC_RTC->CCR |= 2;
// Set the RTC
LPC_RTC->TIME[RTC_TIMETYPE_SECOND] = timeinfo->tm_sec;
LPC_RTC->TIME[RTC_TIMETYPE_MINUTE] = timeinfo->tm_min;
LPC_RTC->TIME[RTC_TIMETYPE_HOUR] = timeinfo->tm_hour;
LPC_RTC->TIME[RTC_TIMETYPE_DAYOFMONTH] = timeinfo->tm_mday;
LPC_RTC->TIME[RTC_TIMETYPE_DAYOFWEEK] = timeinfo->tm_wday;
LPC_RTC->TIME[RTC_TIMETYPE_DAYOFYEAR] = timeinfo->tm_yday;
LPC_RTC->TIME[RTC_TIMETYPE_MONTH] = timeinfo->tm_mon + 1;
LPC_RTC->TIME[RTC_TIMETYPE_YEAR] = timeinfo->tm_year + 1900;
// Restart clock
LPC_RTC->CCR &= ~((uint32_t)2);
}