Diff: targets/TARGET_NXP/TARGET_LPC2460/rtc_api.c

Revision:

0:f269e3021894

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_NXP/TARGET_LPC2460/rtc_api.c	Sun Oct 23 15:10:02 2016 +0000
@@ -0,0 +1,117 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2015 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.
+ */
+#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) {
+    LPC_SC->PCONP |= (1 << PCRTC); // Ensure power is on
+    LPC_RTC->CCR = 0x00;
+    
+    // clock source on 2368 is special test mode on 1768!
+    LPC_RTC->CCR |= 1 << 4;  // Ensure clock source is 32KHz Xtal
+    
+    LPC_RTC->CCR |= 1 << 0; // Ensure the RTC is enabled
+}
+
+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->SEC;
+    timeinfo.tm_min = LPC_RTC->MIN;
+    timeinfo.tm_hour = LPC_RTC->HOUR;
+    timeinfo.tm_mday = LPC_RTC->DOM;
+    timeinfo.tm_mon = LPC_RTC->MONTH - 1;
+    timeinfo.tm_year = LPC_RTC->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->SEC = timeinfo->tm_sec;
+    LPC_RTC->MIN = timeinfo->tm_min;
+    LPC_RTC->HOUR = timeinfo->tm_hour;
+    LPC_RTC->DOM = timeinfo->tm_mday;
+    LPC_RTC->MONTH = timeinfo->tm_mon + 1;
+    LPC_RTC->YEAR = timeinfo->tm_year + 1900;
+    
+    // Restart clock
+    LPC_RTC->CCR &= ~((uint32_t)2);
+}