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Last commit 20 Feb 2019 by mbed official

targets/hal/TARGET_Silicon_Labs/TARGET_EFM32/lp_ticker.c@627:4fa1328d9c60, 2015-09-25 (annotated)

Committer:
mbed_official
Date:
Fri Sep 25 14:15:10 2015 +0100
Revision:
627:4fa1328d9c60
Parent:
548:1abac31e188e 
Synchronized with git revision fe238a91ab7a4d1d72c4cab9da04967c619d54ad



Full URL: https://github.com/mbedmicro/mbed/commit/fe238a91ab7a4d1d72c4cab9da04967c619d54ad/



Silicon Labs - Add support for low-power async Serial

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 627:4fa1328d9c60 1 /***************************************************************************//**
mbed_official 627:4fa1328d9c60 2 * @file lp_ticker.c
mbed_official 627:4fa1328d9c60 3 *******************************************************************************
mbed_official 627:4fa1328d9c60 4 * @section License
mbed_official 627:4fa1328d9c60 5 * <b>(C) Copyright 2015 Silicon Labs, http://www.silabs.com</b>
mbed_official 627:4fa1328d9c60 6 *******************************************************************************
mbed_official 525:c320967f86b9 7 *
mbed_official 627:4fa1328d9c60 8 * Permission is granted to anyone to use this software for any purpose,
mbed_official 627:4fa1328d9c60 9 * including commercial applications, and to alter it and redistribute it
mbed_official 627:4fa1328d9c60 10 * freely, subject to the following restrictions:
mbed_official 525:c320967f86b9 11 *
mbed_official 627:4fa1328d9c60 12 * 1. The origin of this software must not be misrepresented; you must not
mbed_official 627:4fa1328d9c60 13 * claim that you wrote the original software.
mbed_official 627:4fa1328d9c60 14 * 2. Altered source versions must be plainly marked as such, and must not be
mbed_official 627:4fa1328d9c60 15 * misrepresented as being the original software.
mbed_official 627:4fa1328d9c60 16 * 3. This notice may not be removed or altered from any source distribution.
mbed_official 525:c320967f86b9 17 *
mbed_official 627:4fa1328d9c60 18 * DISCLAIMER OF WARRANTY/LIMITATION OF REMEDIES: Silicon Labs has no
mbed_official 627:4fa1328d9c60 19 * obligation to support this Software. Silicon Labs is providing the
mbed_official 627:4fa1328d9c60 20 * Software "AS IS", with no express or implied warranties of any kind,
mbed_official 627:4fa1328d9c60 21 * including, but not limited to, any implied warranties of merchantability
mbed_official 627:4fa1328d9c60 22 * or fitness for any particular purpose or warranties against infringement
mbed_official 627:4fa1328d9c60 23 * of any proprietary rights of a third party.
mbed_official 627:4fa1328d9c60 24 *
mbed_official 627:4fa1328d9c60 25 * Silicon Labs will not be liable for any consequential, incidental, or
mbed_official 627:4fa1328d9c60 26 * special damages, or any other relief, or for any claim by any third party,
mbed_official 627:4fa1328d9c60 27 * arising from your use of this Software.
mbed_official 627:4fa1328d9c60 28 *
mbed_official 627:4fa1328d9c60 29 ******************************************************************************/
mbed_official 525:c320967f86b9 30
mbed_official 525:c320967f86b9 31 #include "device.h"
mbed_official 525:c320967f86b9 32 #if DEVICE_LOWPOWERTIMER
mbed_official 525:c320967f86b9 33
mbed_official 525:c320967f86b9 34 #include "rtc_api.h"
mbed_official 525:c320967f86b9 35 #include "rtc_api_HAL.h"
mbed_official 525:c320967f86b9 36 #include "lp_ticker_api.h"
mbed_official 525:c320967f86b9 37
mbed_official 525:c320967f86b9 38 void lp_ticker_init()
mbed_official 525:c320967f86b9 39 {
mbed_official 525:c320967f86b9 40 rtc_init_real(RTC_INIT_LPTIMER);
mbed_official 525:c320967f86b9 41 rtc_set_comp0_handler((uint32_t)lp_ticker_irq_handler);
mbed_official 525:c320967f86b9 42 }
mbed_official 525:c320967f86b9 43
mbed_official 548:1abac31e188e 44 void lp_ticker_set_interrupt(timestamp_t timestamp)
mbed_official 548:1abac31e188e 45 {
mbed_official 548:1abac31e188e 46 uint64_t timestamp_ticks;
mbed_official 525:c320967f86b9 47 uint64_t current_ticks = RTC_CounterGet();
mbed_official 525:c320967f86b9 48 timestamp_t current_time = ((uint64_t)(current_ticks * 1000000) / (LOW_ENERGY_CLOCK_FREQUENCY / RTC_CLOCKDIV_INT));
mbed_official 548:1abac31e188e 49
mbed_official 548:1abac31e188e 50
mbed_official 525:c320967f86b9 51 /* calculate offset value */
mbed_official 525:c320967f86b9 52 timestamp_t offset = timestamp - current_time;
mbed_official 525:c320967f86b9 53 if(offset > 0xEFFFFFFF) offset = 100;
mbed_official 548:1abac31e188e 54
mbed_official 525:c320967f86b9 55 /* map offset to RTC value */
mbed_official 548:1abac31e188e 56 // ticks = offset * RTC frequency div 1000000
mbed_official 548:1abac31e188e 57 timestamp_ticks = ((uint64_t)offset * (LOW_ENERGY_CLOCK_FREQUENCY / RTC_CLOCKDIV_INT)) / 1000000;
mbed_official 525:c320967f86b9 58 timestamp_ticks += current_ticks;
mbed_official 525:c320967f86b9 59
mbed_official 548:1abac31e188e 60 /* RTC has 24 bit resolution */
mbed_official 548:1abac31e188e 61 timestamp_ticks &= 0xFFFFFF;
mbed_official 525:c320967f86b9 62
mbed_official 525:c320967f86b9 63 /* check for RTC limitation */
mbed_official 525:c320967f86b9 64 if((timestamp_ticks - RTC_CounterGet()) >= 0x800000) timestamp_ticks = RTC_CounterGet() + 2;
mbed_official 548:1abac31e188e 65
mbed_official 548:1abac31e188e 66 /* Set callback */
mbed_official 548:1abac31e188e 67 RTC_FreezeEnable(true);
mbed_official 548:1abac31e188e 68 RTC_CompareSet(0, (uint32_t)timestamp_ticks);
mbed_official 548:1abac31e188e 69 RTC_IntEnable(RTC_IF_COMP0);
mbed_official 548:1abac31e188e 70 RTC_FreezeEnable(false);
mbed_official 525:c320967f86b9 71 }
mbed_official 525:c320967f86b9 72
mbed_official 548:1abac31e188e 73 inline void lp_ticker_disable_interrupt()
mbed_official 548:1abac31e188e 74 {
mbed_official 548:1abac31e188e 75 RTC_IntDisable(RTC_IF_COMP0);
mbed_official 525:c320967f86b9 76 }
mbed_official 525:c320967f86b9 77
mbed_official 548:1abac31e188e 78 inline void lp_ticker_clear_interrupt()
mbed_official 548:1abac31e188e 79 {
mbed_official 548:1abac31e188e 80 RTC_IntClear(RTC_IF_COMP0);
mbed_official 525:c320967f86b9 81 }
mbed_official 525:c320967f86b9 82
mbed_official 548:1abac31e188e 83 timestamp_t lp_ticker_read()
mbed_official 548:1abac31e188e 84 {
mbed_official 548:1abac31e188e 85 uint64_t ticks_temp;
mbed_official 548:1abac31e188e 86 uint64_t ticks = RTC_CounterGet();
mbed_official 525:c320967f86b9 87
mbed_official 548:1abac31e188e 88 /* ticks = counter tick value
mbed_official 548:1abac31e188e 89 * timestamp = value in microseconds
mbed_official 548:1abac31e188e 90 * timestamp = ticks * 1.000.000 / RTC frequency
mbed_official 548:1abac31e188e 91 */
mbed_official 525:c320967f86b9 92
mbed_official 548:1abac31e188e 93 ticks_temp = (ticks * 1000000) / (LOW_ENERGY_CLOCK_FREQUENCY / RTC_CLOCKDIV_INT);
mbed_official 548:1abac31e188e 94 return (timestamp_t) (ticks_temp & 0xFFFFFFFF);
mbed_official 525:c320967f86b9 95 }
mbed_official 525:c320967f86b9 96
mbed_official 525:c320967f86b9 97 #endif