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targets/hal/TARGET_NORDIC/TARGET_MCU_NRF51822/us_ticker.c@304:89b9c3a9a045, 2014-08-29 (annotated)
- Committer:
- mbed_official
- Date:
- Fri Aug 29 17:15:07 2014 +0100
- Revision:
- 304:89b9c3a9a045
- Parent:
- 300:55638feb26a4
- Child:
- 361:56c2a6244bba
Synchronized with git revision 734f365d7da26ef199751f4b0d91611479b495ea
Full URL: https://github.com/mbedmicro/mbed/commit/734f365d7da26ef199751f4b0d91611479b495ea/
1. timestamp_t as an abstraction for time values managed by
Ticker. Using uint64_t for timestamp_t allows a wraparound-free
Ticker. This change forces us to update the definitions of usTicker
for all platforms; but the changes beyond nRF51822 aren't major.
2. reduce power consumption on the nRF51822 by removing the need for
the high-frequency processor timer; and reimplementing it using the
RTC.
I've also replaced high-frequency clock with low-frequency external
clock during system startup of the nRF51822. This brings a major win
in power consumption.
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
mbed_official | 85:e1a8e879a6a9 | 1 | /* mbed Microcontroller Library |
mbed_official | 104:a6a92e2e5a92 | 2 | * Copyright (c) 2013 Nordic Semiconductor |
mbed_official | 85:e1a8e879a6a9 | 3 | * |
mbed_official | 85:e1a8e879a6a9 | 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
mbed_official | 85:e1a8e879a6a9 | 5 | * you may not use this file except in compliance with the License. |
mbed_official | 85:e1a8e879a6a9 | 6 | * You may obtain a copy of the License at |
mbed_official | 85:e1a8e879a6a9 | 7 | * |
mbed_official | 85:e1a8e879a6a9 | 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
mbed_official | 85:e1a8e879a6a9 | 9 | * |
mbed_official | 85:e1a8e879a6a9 | 10 | * Unless required by applicable law or agreed to in writing, software |
mbed_official | 85:e1a8e879a6a9 | 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
mbed_official | 85:e1a8e879a6a9 | 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
mbed_official | 85:e1a8e879a6a9 | 13 | * See the License for the specific language governing permissions and |
mbed_official | 85:e1a8e879a6a9 | 14 | * limitations under the License. |
mbed_official | 85:e1a8e879a6a9 | 15 | */ |
mbed_official | 85:e1a8e879a6a9 | 16 | #include <stddef.h> |
mbed_official | 85:e1a8e879a6a9 | 17 | #include "us_ticker_api.h" |
mbed_official | 85:e1a8e879a6a9 | 18 | #include "cmsis.h" |
mbed_official | 85:e1a8e879a6a9 | 19 | #include "PeripheralNames.h" |
mbed_official | 304:89b9c3a9a045 | 20 | #include "app_timer.h" |
mbed_official | 127:ce7cebc0511f | 21 | |
mbed_official | 304:89b9c3a9a045 | 22 | static bool us_ticker_inited = false; |
mbed_official | 304:89b9c3a9a045 | 23 | static volatile bool us_ticker_appTimerRunning = false; |
mbed_official | 304:89b9c3a9a045 | 24 | static app_timer_id_t us_ticker_appTimerID = TIMER_NULL; |
mbed_official | 300:55638feb26a4 | 25 | |
mbed_official | 300:55638feb26a4 | 26 | void us_ticker_init(void) |
mbed_official | 300:55638feb26a4 | 27 | { |
mbed_official | 304:89b9c3a9a045 | 28 | if (us_ticker_inited) { |
mbed_official | 85:e1a8e879a6a9 | 29 | return; |
mbed_official | 85:e1a8e879a6a9 | 30 | } |
mbed_official | 300:55638feb26a4 | 31 | |
mbed_official | 304:89b9c3a9a045 | 32 | APP_TIMER_INIT(0 /*CFG_TIMER_PRESCALER*/ , 1 /*CFG_TIMER_MAX_INSTANCE*/, 1 /*CFG_TIMER_OPERATION_QUEUE_SIZE*/, false /*CFG_SCHEDULER_ENABLE*/); |
mbed_official | 300:55638feb26a4 | 33 | |
mbed_official | 304:89b9c3a9a045 | 34 | us_ticker_inited = true; |
mbed_official | 85:e1a8e879a6a9 | 35 | } |
mbed_official | 85:e1a8e879a6a9 | 36 | |
mbed_official | 300:55638feb26a4 | 37 | uint32_t us_ticker_read() |
mbed_official | 300:55638feb26a4 | 38 | { |
mbed_official | 304:89b9c3a9a045 | 39 | if (!us_ticker_inited) { |
mbed_official | 304:89b9c3a9a045 | 40 | us_ticker_init(); |
mbed_official | 304:89b9c3a9a045 | 41 | } |
mbed_official | 304:89b9c3a9a045 | 42 | |
mbed_official | 304:89b9c3a9a045 | 43 | timestamp_t value; |
mbed_official | 304:89b9c3a9a045 | 44 | app_timer_cnt_get(&value); /* This returns the RTC counter (which is fed by the 32khz crystal clock source) */ |
mbed_official | 304:89b9c3a9a045 | 45 | return (uint32_t)((value * 1000000) / APP_TIMER_CLOCK_FREQ); /* Return a pseudo microsecond counter value. |
mbed_official | 304:89b9c3a9a045 | 46 | * This is only as precise as the 32khz low-freq |
mbed_official | 304:89b9c3a9a045 | 47 | * clock source, but could be adequate.*/ |
mbed_official | 304:89b9c3a9a045 | 48 | } |
mbed_official | 304:89b9c3a9a045 | 49 | |
mbed_official | 304:89b9c3a9a045 | 50 | /* An adaptor to interface us_ticker_irq_handler with the app_timer callback. |
mbed_official | 304:89b9c3a9a045 | 51 | * Needed because the irq_handler() doesn't take any parameter.*/ |
mbed_official | 304:89b9c3a9a045 | 52 | static void us_ticker_app_timer_callback(void *context) |
mbed_official | 304:89b9c3a9a045 | 53 | { |
mbed_official | 304:89b9c3a9a045 | 54 | us_ticker_appTimerRunning = false; |
mbed_official | 304:89b9c3a9a045 | 55 | us_ticker_irq_handler(); |
mbed_official | 304:89b9c3a9a045 | 56 | } |
mbed_official | 304:89b9c3a9a045 | 57 | |
mbed_official | 304:89b9c3a9a045 | 58 | void us_ticker_set_interrupt(timestamp_t timestamp) |
mbed_official | 304:89b9c3a9a045 | 59 | { |
mbed_official | 304:89b9c3a9a045 | 60 | if (!us_ticker_inited) { |
mbed_official | 85:e1a8e879a6a9 | 61 | us_ticker_init(); |
mbed_official | 85:e1a8e879a6a9 | 62 | } |
mbed_official | 300:55638feb26a4 | 63 | |
mbed_official | 304:89b9c3a9a045 | 64 | if (us_ticker_appTimerID == TIMER_NULL) { |
mbed_official | 304:89b9c3a9a045 | 65 | if (app_timer_create(&us_ticker_appTimerID, APP_TIMER_MODE_SINGLE_SHOT, us_ticker_app_timer_callback) != NRF_SUCCESS) { |
mbed_official | 304:89b9c3a9a045 | 66 | /* placeholder to do something to recover from error */ |
mbed_official | 304:89b9c3a9a045 | 67 | return; |
mbed_official | 304:89b9c3a9a045 | 68 | } |
mbed_official | 300:55638feb26a4 | 69 | } |
mbed_official | 85:e1a8e879a6a9 | 70 | |
mbed_official | 304:89b9c3a9a045 | 71 | if (us_ticker_appTimerRunning) { |
mbed_official | 304:89b9c3a9a045 | 72 | return; |
mbed_official | 300:55638feb26a4 | 73 | } |
mbed_official | 300:55638feb26a4 | 74 | |
mbed_official | 304:89b9c3a9a045 | 75 | timestamp_t currentCounter64; |
mbed_official | 304:89b9c3a9a045 | 76 | app_timer_cnt_get(¤tCounter64); |
mbed_official | 304:89b9c3a9a045 | 77 | uint32_t currentCounter = currentCounter64 & MAX_RTC_COUNTER_VAL; |
mbed_official | 304:89b9c3a9a045 | 78 | uint32_t targetCounter = ((uint32_t)((timestamp * (uint64_t)APP_TIMER_CLOCK_FREQ) / 1000000) + 1) & MAX_RTC_COUNTER_VAL; |
mbed_official | 304:89b9c3a9a045 | 79 | uint32_t ticksToCount = (targetCounter >= currentCounter) ? |
mbed_official | 304:89b9c3a9a045 | 80 | (targetCounter - currentCounter) : (MAX_RTC_COUNTER_VAL + 1) - (currentCounter - targetCounter); |
mbed_official | 304:89b9c3a9a045 | 81 | if (ticksToCount > 0) { |
mbed_official | 304:89b9c3a9a045 | 82 | uint32_t rc; |
mbed_official | 304:89b9c3a9a045 | 83 | rc = app_timer_start(us_ticker_appTimerID, ticksToCount, NULL /*p_context*/); |
mbed_official | 304:89b9c3a9a045 | 84 | if (rc != NRF_SUCCESS) { |
mbed_official | 304:89b9c3a9a045 | 85 | /* placeholder to do something to recover from error */ |
mbed_official | 304:89b9c3a9a045 | 86 | return; |
mbed_official | 300:55638feb26a4 | 87 | } |
mbed_official | 304:89b9c3a9a045 | 88 | us_ticker_appTimerRunning = true; |
mbed_official | 300:55638feb26a4 | 89 | } |
mbed_official | 85:e1a8e879a6a9 | 90 | } |
mbed_official | 85:e1a8e879a6a9 | 91 | |
mbed_official | 300:55638feb26a4 | 92 | void us_ticker_disable_interrupt(void) |
mbed_official | 300:55638feb26a4 | 93 | { |
mbed_official | 304:89b9c3a9a045 | 94 | if (us_ticker_appTimerRunning) { |
mbed_official | 304:89b9c3a9a045 | 95 | app_timer_stop(us_ticker_appTimerID); |
mbed_official | 304:89b9c3a9a045 | 96 | } |
mbed_official | 85:e1a8e879a6a9 | 97 | } |
mbed_official | 300:55638feb26a4 | 98 | |
mbed_official | 300:55638feb26a4 | 99 | void us_ticker_clear_interrupt(void) |
mbed_official | 300:55638feb26a4 | 100 | { |
mbed_official | 304:89b9c3a9a045 | 101 | if (us_ticker_appTimerRunning) { |
mbed_official | 304:89b9c3a9a045 | 102 | app_timer_stop(us_ticker_appTimerID); |
mbed_official | 304:89b9c3a9a045 | 103 | } |
mbed_official | 85:e1a8e879a6a9 | 104 | } |