Diff: targets/TARGET_ONSEMI/TARGET_NCS36510/rtc.c

Revision:

149:156823d33999

Child:

150:02e0a0aed4ec

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_ONSEMI/TARGET_NCS36510/rtc.c	Fri Oct 28 11:17:30 2016 +0100
@@ -0,0 +1,285 @@
+/**
+ *******************************************************************************
+ * @file    rtc.c
+ * @brief Implementation of a Rtc driver
+ * @internal
+ * @author  ON Semiconductor
+ * $Rev: 3525 $
+ * $Date: 2015-07-20 15:24:25 +0530 (Mon, 20 Jul 2015) $
+ ******************************************************************************
+ * Copyright 2016 Semiconductor Components Industries LLC (d/b/a “ON Semiconductor”).
+ * All rights reserved.  This software and/or documentation is licensed by ON Semiconductor
+ * under limited terms and conditions.  The terms and conditions pertaining to the software
+ * and/or documentation are available at http://www.onsemi.com/site/pdf/ONSEMI_T&C.pdf
+ * (“ON Semiconductor Standard Terms and Conditions of Sale, Section 8 Software”) and
+ * if applicable the software license agreement.  Do not use this software and/or
+ * documentation unless you have carefully read and you agree to the limited terms and
+ * conditions.  By using this software and/or documentation, you agree to the limited
+ * terms and conditions.
+ *
+ * THIS SOFTWARE IS PROVIDED "AS IS".  NO WARRANTIES, WHETHER EXPRESS, IMPLIED
+ * OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE.
+ * ON SEMICONDUCTOR SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL,
+ * INCIDENTAL, OR CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.
+ * @endinternal
+ *
+ * @ingroup rtc
+ *
+ * @details
+ * A real-time clock (RTC) is a computer clock ,that keeps track of the current time.  The heart of the RTC is a series of
+ * freely running counters one for each time unit, The series of counters is linked as follows: a roll over event of
+ * the seconds counter produces a minutes enable pulse; a roll over event of the minutes counter produces an hours
+ * enable pulse, etc.Note that all Counter registers are in an undefined state on power-up.
+ * Use the Reset bit in the Control Register to reset the counters to their default values.
+ * DIVISOR is the register containing the value to divide the clock frequency to produce 1Hz strobe ; 1Hz strobe is used
+ * internally to time the incrementing of the Seconds Counter.
+ * There is a set of register to set the values in the counter for each time unit.from where time is start to increment.
+ * There is another set of register to set the ALARM ...Each of the Alarm Registers can be programmed with a value that
+ * is used to compare to a Counter Register in order to produce an alarm (an interrupt) when the values match.
+ * There is a programmable bit in each Alarm Register that determines if the alarm occurs upon a value match, or
+ * if the alarm occurs upon a Counter increment condition.
+ *
+ */
+#include "rtc.h"
+#include "mbed_assert.h"
+
+static uint16_t SubSecond;
+static uint64_t LastRtcTimeus;
+
+/* See rtc.h for details */
+void fRtcInit(void)
+{
+    CLOCK_ENABLE(CLOCK_RTC);             /* enable rtc peripheral */
+    CLOCKREG->CCR.BITS.RTCEN = True;     /* Enable RTC clock 32K */
+
+    /* Reset RTC control register */
+    RTCREG->CONTROL.WORD     = False;
+
+    /* Initialize all counters */
+    RTCREG->SECOND_COUNTER       = False;
+    RTCREG->SUB_SECOND_COUNTER   = False;
+    RTCREG->SECOND_ALARM         = False;
+    RTCREG->SUB_SECOND_ALARM     = False;
+    LastRtcTimeus = 0;
+
+    /* Reset RTC Status register */
+    RTCREG->STATUS.WORD      = False;
+
+    /* Clear interrupt status */
+    RTCREG->INT_CLEAR.WORD   = False;
+
+    /* Start sec & sub_sec counter */
+    while(RTCREG->STATUS.BITS.BSY_CTRL_REG_WRT == True);/* Wait previous write to complete */
+    RTCREG->CONTROL.WORD |= ((True << RTC_CONTROL_SUBSEC_CNT_START_BIT_POS) |
+                             (True << RTC_CONTROL_SEC_CNT_START_BIT_POS));
+
+    /* enable interruption associated with the rtc at NVIC level */
+    NVIC_SetVector(Rtc_IRQn,(uint32_t)fRtcHandler); /* TODO define lp_ticker_isr */
+    NVIC_ClearPendingIRQ(Rtc_IRQn);
+    NVIC_EnableIRQ(Rtc_IRQn);
+
+    while(RTCREG->STATUS.BITS.BSY_CTRL_REG_WRT == True); /* Wait for RTC to finish writing register - RTC operates on 32K clock as compared to 32M core*/
+
+    return;
+}
+
+/* See rtc.h for details */
+void fRtcFree(void)
+{
+    /* Reset RTC control register */
+    RTCREG->CONTROL.WORD = False;
+
+    /* disable interruption associated with the rtc */
+    NVIC_DisableIRQ(Rtc_IRQn);
+
+    while(RTCREG->STATUS.BITS.BSY_CTRL_REG_WRT == True); /* Wait for RTC to finish writing register - RTC operates on 32K clock as compared to 32M core*/
+}
+
+/* See rtc.h for details */
+void fRtcSetInterrupt(uint32_t timestamp)
+{
+    SubSecond             = False;
+    uint32_t Second       = False;
+    uint8_t DividerAdjust = 1;
+
+    if(timestamp) {
+        if(timestamp >= RTC_SEC_TO_US) {
+            /* TimeStamp is big enough to set second alarm */
+            Second =  ((timestamp / RTC_SEC_TO_US) & RTC_SEC_MASK); /* Convert micro second to second */
+            RTCREG->SECOND_ALARM = Second; /* Write to alarm register */
+
+            /* Enable second interrupt */
+            RTCREG->CONTROL.WORD |= (True << RTC_CONTROL_SEC_CNT_INT_BIT_POS);
+        }
+        timestamp = timestamp - Second * RTC_SEC_TO_US; /* Take out micro second for sub second alarm */
+        if(timestamp > False) {
+            /* We have some thing for sub second */
+
+            /* Convert micro second to sub_seconds(each count = 30.5 us) */
+            if(timestamp > 131000) {
+                DividerAdjust = 100;
+            }
+
+            volatile uint64_t Temp = (timestamp / DividerAdjust * RTC_CLOCK_HZ);
+            Temp = (uint64_t)(Temp / RTC_SEC_TO_US * DividerAdjust);
+            SubSecond = Temp & RTC_SUB_SEC_MASK;
+
+            if(SubSecond <= 5) {
+                SubSecond = 0;
+            }
+
+
+            if(SubSecond > False) {
+                /* Second interrupt not enabled */
+
+                /* Set SUB SEC_ALARM */
+                RTCREG->SUB_SECOND_ALARM = SubSecond;    /* Write to sub second alarm */
+
+                /* Enable sub second interrupt */
+                while(RTCREG->STATUS.BITS.BSY_CTRL_REG_WRT == True);
+                RTCREG->CONTROL.WORD |= (True << RTC_CONTROL_SUBSEC_CNT_INT_BIT_POS);
+            }
+        }
+
+        while(RTCREG->STATUS.BITS.BSY_ANY_WRT == True); /* Wait for RTC to finish writing register - RTC operates on 32K clock as compared to 32M core*/
+    }
+    return;
+}
+
+/* See rtc.h for details */
+void fRtcDisableInterrupt(void)
+{
+    /* Disable subsec/sec interrupt */
+    RTCREG->CONTROL.WORD &= ~((RTC_ALL_INTERRUPT_BIT_VAL) << RTC_CONTROL_SUBSEC_CNT_INT_BIT_POS);
+    while(RTCREG->STATUS.BITS.BSY_CTRL_REG_WRT == True); /* Wait for RTC to finish writing register - RTC operates on 32K clock as compared to 32M core*/
+}
+
+/* See rtc.h for details */
+void fRtcEnableInterrupt(void)
+{
+    /* Disable subsec/sec interrupt */
+    RTCREG->CONTROL.WORD |= ((RTC_ALL_INTERRUPT_BIT_VAL) << RTC_CONTROL_SUBSEC_CNT_INT_BIT_POS);
+    while(RTCREG->STATUS.BITS.BSY_CTRL_REG_WRT == True); /* Wait for RTC to finish writing register - RTC operates on 32K clock as compared to 32M core*/
+}
+
+/* See rtc.h for details */
+void fRtcClearInterrupt(void)
+{
+    /* Disable subsec/sec interrupt */
+    /* Clear sec & sub_sec interrupts */
+    RTCREG->INT_CLEAR.WORD = ((True << RTC_INT_CLR_SUB_SEC_BIT_POS) |
+                              (True << RTC_INT_CLR_SEC_BIT_POS));
+    while(RTCREG->STATUS.BITS.BSY_ANY_WRT == True); /* Wait for RTC to finish writing register - RTC operates on 32K clock as compared to 32M core*/
+}
+
+/* See rtc.h for details */
+uint64_t fRtcRead(void)
+{
+    uint32_t Second;
+    uint16_t SubSecond;
+
+    /* Hardware Bug fix: The rollover of the sub-second counter initiates the increment of the second counter.
+     * That means there is one cycle where the sub-second has rolled back to zero and the second counter has not incremented
+     * and a read during that cycle will be incorrect.  That will occur for one RTC cycle and that is about 31us of exposure.
+     * If you read a zero in the sub-second counter then increment the second counter by 1.
+     * Alternatively, subtract 1 from the Sub-seconds counter to align the Second and Sub-Second rollover.
+     */
+
+    /* Read the Second and Sub-second counters, then read the Second counter again.
+     * If it changed, then the Second rolled over while reading Sub-seconds, so go back and read them both again.
+     */
+
+    do {
+        Second       = RTCREG->SECOND_COUNTER;        /* Get SEC_COUNTER reg value */
+        SubSecond    = (RTCREG->SUB_SECOND_COUNTER - 1) & 0x7FFF;      /* Get SUB_SEC_COUNTER reg value */
+    } while (Second != RTCREG->SECOND_COUNTER);                     /* Repeat if the second has changed */
+
+    //note: casting to float removed to avoid reduction in resolution
+    uint64_t RtcTimeus = ((uint64_t)SubSecond * RTC_SEC_TO_US / RTC_CLOCK_HZ) + ((uint64_t)Second * RTC_SEC_TO_US);
+
+    /*check that the time did not go backwards */
+    MBED_ASSERT(RtcTimeus >= LastRtcTimeus);
+    LastRtcTimeus = RtcTimeus;
+
+    return RtcTimeus;
+}
+
+/* See rtc.h for details */
+void fRtcWrite(uint64_t RtcTimeus)
+{
+    uint32_t Second       = 0;
+    uint16_t SubSecond    = 0;
+    /* Stop RTC */
+    RTCREG->CONTROL.WORD &= ~((True << RTC_CONTROL_SUBSEC_CNT_START_BIT_POS) |
+                              (True << RTC_CONTROL_SEC_CNT_START_BIT_POS));
+
+    if(RtcTimeus > RTC_SEC_TO_US) {
+        /* TimeStamp is big enough to set second counter */
+        Second =  ((RtcTimeus / RTC_SEC_TO_US) & RTC_SEC_MASK);
+    }
+    RTCREG->SECOND_COUNTER = Second;
+    RtcTimeus = RtcTimeus - (Second * RTC_SEC_TO_US);
+    if(RtcTimeus > False) {
+        /* Convert TimeStamp to sub_seconds */
+        SubSecond =  (uint16_t)((float)(RtcTimeus * RTC_CLOCK_HZ / RTC_SEC_TO_US)) & RTC_SUB_SEC_MASK;
+    }
+    /* Set SUB_SEC_ALARM */
+    RTCREG->SUB_SECOND_COUNTER = SubSecond;
+
+    while(RTCREG->STATUS.BITS.BSY_CTRL_REG_WRT == True); /* Wait for RTC to finish writing register - RTC operates on 32K clock as compared to 32M core*/
+    /* Start RTC */
+    RTCREG->CONTROL.WORD |= ((True << RTC_CONTROL_SUBSEC_CNT_START_BIT_POS) |
+                             (True << RTC_CONTROL_SEC_CNT_START_BIT_POS));
+
+    while(RTCREG->STATUS.BITS.BSY_ANY_WRT == True); /* Wait for RTC to finish writing register - RTC operates on 32K clock as compared to 32M core*/
+}
+
+/* See rtc.h for details */
+void fRtcHandler(void)
+{
+    /* SUB_SECOND/SECOND interrupt occured */
+    volatile uint32_t TempStatus = RTCREG->STATUS.WORD;
+
+    /* Disable RTC interrupt */
+    NVIC_DisableIRQ(Rtc_IRQn);
+
+    /* Clear sec & sub_sec interrupts */
+    RTCREG->INT_CLEAR.WORD = ((True << RTC_INT_CLR_SUB_SEC_BIT_POS) |
+                              (True << RTC_INT_CLR_SEC_BIT_POS));
+
+    /* TODO  ANDing SUB_SEC & SEC interrupt - work around for RTC issue - will be resolved in REV G */
+    if(TempStatus & RTC_SEC_INT_STATUS_MASK) {
+        /* Second interrupt occured */
+        if(SubSecond > False) {
+            /* Set SUB SEC_ALARM */
+            RTCREG->SUB_SECOND_ALARM = SubSecond + RTCREG->SUB_SECOND_COUNTER;
+            /* Enable sub second interrupt */
+            RTCREG->CONTROL.WORD |= (True << RTC_CONTROL_SUBSEC_CNT_INT_BIT_POS);
+        } else {
+            /* We reach here after second interrupt is occured */
+            RTCREG->CONTROL.WORD &= ~(True << RTC_CONTROL_SUBSEC_CNT_INT_BIT_POS) |
+                                    (True << RTC_CONTROL_SEC_CNT_INT_BIT_POS);
+        }
+    } else {
+        /* We reach here after sub_second or (Sub second + second) interrupt occured */
+		/* Disable Second and sub_second interrupt */
+        RTCREG->CONTROL.WORD &= ~(True << RTC_CONTROL_SUBSEC_CNT_INT_BIT_POS) |
+                                (True << RTC_CONTROL_SEC_CNT_INT_BIT_POS);
+    }
+
+	NVIC_EnableIRQ(Rtc_IRQn);
+	
+	while(RTCREG->STATUS.BITS.BSY_ANY_WRT == True); /* Wait for RTC to finish writing register - RTC operates on 32K clock as compared to 32M core*/
+	
+	lp_ticker_irq_handler();
+}
+
+boolean fIsRtcEnabled(void)
+{
+    if(RTCREG->CONTROL.BITS.SUB_SEC_COUNTER_EN | RTCREG->CONTROL.BITS.SEC_COUNTER_EN) {
+        return True;
+    } else {
+        return False;
+    }
+}