Johannes Stratmann / mbed-dev

added prescaler for 16 bit pwm in LPC1347 target

Fork of mbed-dev by mbed official

targets/hal/TARGET_ONSEMI/TARGET_NCS36510/ncs36510_lp_ticker_api.c@147:ba84b7dc41a7, 2016-09-10 (annotated)

Committer:
JojoS
Date:
Sat Sep 10 15:32:04 2016 +0000
Revision:
147:ba84b7dc41a7
Parent:
144:ef7eb2e8f9f7 
added prescaler for 16 bit timers (solution as in LPC11xx), default prescaler 31 for max 28 ms period time

Who changed what in which revision?

UserRevisionLine numberNew contents of line
<> 144:ef7eb2e8f9f7 1 /**
<> 144:ef7eb2e8f9f7 2 *******************************************************************************
<> 144:ef7eb2e8f9f7 3 * @file lpticker.c
<> 144:ef7eb2e8f9f7 4 * @brief Implementation of a Low Power Ticker functionality based on RTC
<> 144:ef7eb2e8f9f7 5 * @internal
<> 144:ef7eb2e8f9f7 6 * @author ON Semiconductor
<> 144:ef7eb2e8f9f7 7 * $Rev: $
<> 144:ef7eb2e8f9f7 8 * $Date: $
<> 144:ef7eb2e8f9f7 9 ******************************************************************************
<> 144:ef7eb2e8f9f7 10 * @copyright (c) 2015 ON Semiconductor. All rights reserved.
<> 144:ef7eb2e8f9f7 11 * ON Semiconductor is supplying this software for use with ON Semiconductor
<> 144:ef7eb2e8f9f7 12 * processor based microcontrollers only.
<> 144:ef7eb2e8f9f7 13 *
<> 144:ef7eb2e8f9f7 14 * THIS SOFTWARE IS PROVIDED "AS IS". NO WARRANTIES, WHETHER EXPRESS, IMPLIED
<> 144:ef7eb2e8f9f7 15 * OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF
<> 144:ef7eb2e8f9f7 16 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE.
<> 144:ef7eb2e8f9f7 17 * ON SEMICONDUCTOR SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL,
<> 144:ef7eb2e8f9f7 18 * INCIDENTAL, OR CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.
<> 144:ef7eb2e8f9f7 19 * @endinternal
<> 144:ef7eb2e8f9f7 20 *
<> 144:ef7eb2e8f9f7 21 * @ingroup lpticker
<> 144:ef7eb2e8f9f7 22 *
<> 144:ef7eb2e8f9f7 23 * @details
<> 144:ef7eb2e8f9f7 24 * This is Low Power ticker derived from RTC
<> 144:ef7eb2e8f9f7 25 *
<> 144:ef7eb2e8f9f7 26 */
<> 144:ef7eb2e8f9f7 27
<> 144:ef7eb2e8f9f7 28 #include "device.h"
<> 144:ef7eb2e8f9f7 29 #if DEVICE_LOWPOWERTIMER
<> 144:ef7eb2e8f9f7 30
<> 144:ef7eb2e8f9f7 31 #include "sleep_api.h"
<> 144:ef7eb2e8f9f7 32 #include "cmsis_nvic.h"
<> 144:ef7eb2e8f9f7 33 #include "lp_ticker_api.h"
<> 144:ef7eb2e8f9f7 34 #include "rtc.h"
<> 144:ef7eb2e8f9f7 35 #include "rtc_map.h"
<> 144:ef7eb2e8f9f7 36 #include "sleep.h"
<> 144:ef7eb2e8f9f7 37
<> 144:ef7eb2e8f9f7 38 /* Initialize the RTC for low power ticker */
<> 144:ef7eb2e8f9f7 39 void lp_ticker_init()
<> 144:ef7eb2e8f9f7 40 {
<> 144:ef7eb2e8f9f7 41 fRtcInit();
<> 144:ef7eb2e8f9f7 42 }
<> 144:ef7eb2e8f9f7 43
<> 144:ef7eb2e8f9f7 44 /* Return the current RTC counter value in us */
<> 144:ef7eb2e8f9f7 45 uint32_t lp_ticker_read()
<> 144:ef7eb2e8f9f7 46 {
<> 144:ef7eb2e8f9f7 47 return (uint32_t)(fRtcRead() & 0xFFFFFFFF); /* TODO Truncating 64 bit value to 32 bit */
<> 144:ef7eb2e8f9f7 48 }
<> 144:ef7eb2e8f9f7 49
<> 144:ef7eb2e8f9f7 50 /* Set interrupt for specified time */
<> 144:ef7eb2e8f9f7 51 void lp_ticker_set_interrupt(timestamp_t timestamp)
<> 144:ef7eb2e8f9f7 52 {
<> 144:ef7eb2e8f9f7 53 /* The RTC Match register needs to be Set to the RTC alarm value */
<> 144:ef7eb2e8f9f7 54 fRtcSetInterrupt(timestamp);
<> 144:ef7eb2e8f9f7 55 }
<> 144:ef7eb2e8f9f7 56
<> 144:ef7eb2e8f9f7 57 /*Return the time that gets cut off when you return just a 32 bit us resolution number */
<> 144:ef7eb2e8f9f7 58 uint32_t lp_ticker_get_overflows_counter(void)
<> 144:ef7eb2e8f9f7 59 {
<> 144:ef7eb2e8f9f7 60 /* To check; do we need an counter in software in RTC to find overflows */
<> 144:ef7eb2e8f9f7 61 uint64_t now = fRtcRead();
<> 144:ef7eb2e8f9f7 62 uint32_t overflow = (now & 0xFFFFFFFF00000000) >> 32;
<> 144:ef7eb2e8f9f7 63 return overflow;
<> 144:ef7eb2e8f9f7 64 }
<> 144:ef7eb2e8f9f7 65
<> 144:ef7eb2e8f9f7 66 /* Return the RTC Match counter contents */
<> 144:ef7eb2e8f9f7 67 uint32_t lp_ticker_get_compare_match()
<> 144:ef7eb2e8f9f7 68 {
<> 144:ef7eb2e8f9f7 69 /* read the alarms and convert to us */
<> 144:ef7eb2e8f9f7 70 uint16_t sub_second_alarm = RTCREG->SUB_SECOND_ALARM;
<> 144:ef7eb2e8f9f7 71 uint32_t second_alarm = RTCREG->SECOND_ALARM;
<> 144:ef7eb2e8f9f7 72 uint64_t alarm_us = (uint64_t)((((float)sub_second_alarm / RTC_CLOCK_HZ) * RTC_SEC_TO_US) +
<> 144:ef7eb2e8f9f7 73 (second_alarm * RTC_SEC_TO_US));
<> 144:ef7eb2e8f9f7 74 /* TODO truncating to 32 bits */
<> 144:ef7eb2e8f9f7 75 return (uint32_t)(alarm_us & 0xFFFFFFFF);
<> 144:ef7eb2e8f9f7 76 }
<> 144:ef7eb2e8f9f7 77
<> 144:ef7eb2e8f9f7 78 /* sleep until alarm */
<> 144:ef7eb2e8f9f7 79 void lp_ticker_sleep_until(uint32_t now, uint32_t time)
<> 144:ef7eb2e8f9f7 80 {
<> 144:ef7eb2e8f9f7 81 /* Set the interrupt */
<> 144:ef7eb2e8f9f7 82 lp_ticker_set_interrupt(time);
<> 144:ef7eb2e8f9f7 83
<> 144:ef7eb2e8f9f7 84 /* Go to sleep */
<> 144:ef7eb2e8f9f7 85 sleep_t obj;
<> 144:ef7eb2e8f9f7 86 obj.SleepType = SLEEP_TYPE_NONE;
<> 144:ef7eb2e8f9f7 87 obj.timeToSleep = time - now;
<> 144:ef7eb2e8f9f7 88
<> 144:ef7eb2e8f9f7 89 mbed_enter_sleep(&obj);
<> 144:ef7eb2e8f9f7 90 /* TBD: This is dummy exit for now; once the entered sleep it should be
<> 144:ef7eb2e8f9f7 91 removed and sleep exit should happen through interrupt */
<> 144:ef7eb2e8f9f7 92 mbed_exit_sleep(&obj);
<> 144:ef7eb2e8f9f7 93 }
<> 144:ef7eb2e8f9f7 94
<> 144:ef7eb2e8f9f7 95 /** Disable low power ticker interrupt
<> 144:ef7eb2e8f9f7 96 *
<> 144:ef7eb2e8f9f7 97 */
<> 144:ef7eb2e8f9f7 98 void lp_ticker_disable_interrupt(void)
<> 144:ef7eb2e8f9f7 99 {
<> 144:ef7eb2e8f9f7 100 /* TODO : This is an empty implementation for now */
<> 144:ef7eb2e8f9f7 101 }
<> 144:ef7eb2e8f9f7 102
<> 144:ef7eb2e8f9f7 103 /** Clear the low power ticker interrupt
<> 144:ef7eb2e8f9f7 104 *
<> 144:ef7eb2e8f9f7 105 */
<> 144:ef7eb2e8f9f7 106 void lp_ticker_clear_interrupt(void)
<> 144:ef7eb2e8f9f7 107 {
<> 144:ef7eb2e8f9f7 108 /* TODO : This is an empty implementation for now */
<> 144:ef7eb2e8f9f7 109 }
<> 144:ef7eb2e8f9f7 110
<> 144:ef7eb2e8f9f7 111 #endif /* DEVICE_LOWPOWERTIMER */