Thomas Butler
fsdfds
Dependencies: BLE_API mbed-dev-bin nRF51822
Fork of
microbit-dal
by 
Lancaster University
source/core/MicroBitSystemTimer.cpp@75:b02b061aed24, 2018-08-14 (annotated)
- Committer:
- tb942
- Date:
- Tue Aug 14 18:30:43 2018 +0000
- Revision:
- 75:b02b061aed24
- Parent:
- 49:88f03f3feff1
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| Jonathan Austin |
1:8aa5cdb4ab67 | 1 | /* |
| Jonathan Austin |
1:8aa5cdb4ab67 | 2 | The MIT License (MIT) |
| Jonathan Austin |
1:8aa5cdb4ab67 | 3 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 4 | Copyright (c) 2016 British Broadcasting Corporation. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 5 | This software is provided by Lancaster University by arrangement with the BBC. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 6 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 7 | Permission is hereby granted, free of charge, to any person obtaining a |
| Jonathan Austin |
1:8aa5cdb4ab67 | 8 | copy of this software and associated documentation files (the "Software"), |
| Jonathan Austin |
1:8aa5cdb4ab67 | 9 | to deal in the Software without restriction, including without limitation |
| Jonathan Austin |
1:8aa5cdb4ab67 | 10 | the rights to use, copy, modify, merge, publish, distribute, sublicense, |
| Jonathan Austin |
1:8aa5cdb4ab67 | 11 | and/or sell copies of the Software, and to permit persons to whom the |
| Jonathan Austin |
1:8aa5cdb4ab67 | 12 | Software is furnished to do so, subject to the following conditions: |
| Jonathan Austin |
1:8aa5cdb4ab67 | 13 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 14 | The above copyright notice and this permission notice shall be included in |
| Jonathan Austin |
1:8aa5cdb4ab67 | 15 | all copies or substantial portions of the Software. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 16 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 17 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| Jonathan Austin |
1:8aa5cdb4ab67 | 18 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| Jonathan Austin |
1:8aa5cdb4ab67 | 19 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| Jonathan Austin |
1:8aa5cdb4ab67 | 20 | THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| Jonathan Austin |
1:8aa5cdb4ab67 | 21 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
| Jonathan Austin |
1:8aa5cdb4ab67 | 22 | FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
| Jonathan Austin |
1:8aa5cdb4ab67 | 23 | DEALINGS IN THE SOFTWARE. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 24 | */ |
| Jonathan Austin |
1:8aa5cdb4ab67 | 25 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 26 | /** |
| Jonathan Austin |
1:8aa5cdb4ab67 | 27 | * Definitions for the MicroBit system timer. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 28 | * |
| Jonathan Austin |
1:8aa5cdb4ab67 | 29 | * This module provides: |
| Jonathan Austin |
1:8aa5cdb4ab67 | 30 | * |
| Jonathan Austin |
1:8aa5cdb4ab67 | 31 | * 1) a concept of global system time since power up |
| Jonathan Austin |
1:8aa5cdb4ab67 | 32 | * 2) a simple periodic multiplexing API for the underlying mbed implementation. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 33 | * |
| Jonathan Austin |
1:8aa5cdb4ab67 | 34 | * The latter is useful to avoid costs associated with multiple mbed Ticker instances |
| Jonathan Austin |
1:8aa5cdb4ab67 | 35 | * in microbit-dal components, as each incurs a significant additional RAM overhead (circa 80 bytes). |
| Jonathan Austin |
1:8aa5cdb4ab67 | 36 | */ |
| Jonathan Austin |
1:8aa5cdb4ab67 | 37 | #include "MicroBitConfig.h" |
| Jonathan Austin |
1:8aa5cdb4ab67 | 38 | #include "MicroBitSystemTimer.h" |
| Jonathan Austin |
1:8aa5cdb4ab67 | 39 | #include "ErrorNo.h" |
| Jonathan Austin |
1:8aa5cdb4ab67 | 40 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 41 | /* |
| Jonathan Austin |
1:8aa5cdb4ab67 | 42 | * Time since power on. Measured in milliseconds. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 43 | * When stored as an unsigned long, this gives us approx 50 days between rollover, which is ample. :-) |
| Jonathan Austin |
1:8aa5cdb4ab67 | 44 | */ |
| LancasterUniversity | 49:88f03f3feff1 | 45 | static uint64_t time_us = 0; |
| Jonathan Austin |
1:8aa5cdb4ab67 | 46 | static unsigned int tick_period = 0; |
| Jonathan Austin |
1:8aa5cdb4ab67 | 47 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 48 | // Array of components which are iterated during a system tick |
| Jonathan Austin |
1:8aa5cdb4ab67 | 49 | static MicroBitComponent* systemTickComponents[MICROBIT_SYSTEM_COMPONENTS]; |
| Jonathan Austin |
1:8aa5cdb4ab67 | 50 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 51 | // Periodic callback interrupt |
| LancasterUniversity | 49:88f03f3feff1 | 52 | static Ticker *ticker = NULL; |
| LancasterUniversity | 49:88f03f3feff1 | 53 | |
| LancasterUniversity | 49:88f03f3feff1 | 54 | // System timer. |
| LancasterUniversity | 49:88f03f3feff1 | 55 | static Timer *timer = NULL; |
| Jonathan Austin |
1:8aa5cdb4ab67 | 56 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 57 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 58 | /** |
| LancasterUniversity | 49:88f03f3feff1 | 59 | * Initialises a system wide timer, used to drive the various components used in the runtime. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 60 | * |
| Jonathan Austin |
1:8aa5cdb4ab67 | 61 | * This must be called before any components register to receive periodic periodic callbacks. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 62 | * |
| Jonathan Austin |
1:8aa5cdb4ab67 | 63 | * @param timer_period The initial period between interrupts, in millseconds. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 64 | * |
| Jonathan Austin |
1:8aa5cdb4ab67 | 65 | * @return MICROBIT_OK on success. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 66 | */ |
| Jonathan Austin |
1:8aa5cdb4ab67 | 67 | int system_timer_init(int period) |
| Jonathan Austin |
1:8aa5cdb4ab67 | 68 | { |
| LancasterUniversity | 49:88f03f3feff1 | 69 | if (ticker == NULL) |
| LancasterUniversity | 49:88f03f3feff1 | 70 | ticker = new Ticker(); |
| LancasterUniversity | 49:88f03f3feff1 | 71 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 72 | if (timer == NULL) |
| LancasterUniversity | 49:88f03f3feff1 | 73 | { |
| LancasterUniversity | 49:88f03f3feff1 | 74 | timer = new Timer(); |
| LancasterUniversity | 49:88f03f3feff1 | 75 | timer->start(); |
| LancasterUniversity | 49:88f03f3feff1 | 76 | } |
| Jonathan Austin |
1:8aa5cdb4ab67 | 77 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 78 | return system_timer_set_period(period); |
| Jonathan Austin |
1:8aa5cdb4ab67 | 79 | } |
| Jonathan Austin |
1:8aa5cdb4ab67 | 80 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 81 | /** |
| Jonathan Austin |
1:8aa5cdb4ab67 | 82 | * Reconfigures the system wide timer to the given period in milliseconds. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 83 | * |
| Jonathan Austin |
1:8aa5cdb4ab67 | 84 | * @param period the new period of the timer in milliseconds |
| Jonathan Austin |
1:8aa5cdb4ab67 | 85 | * |
| Jonathan Austin |
1:8aa5cdb4ab67 | 86 | * @return MICROBIT_OK on success. MICROBIT_INVALID_PARAMETER is returned if period < 1 |
| Jonathan Austin |
1:8aa5cdb4ab67 | 87 | */ |
| Jonathan Austin |
1:8aa5cdb4ab67 | 88 | int system_timer_set_period(int period) |
| Jonathan Austin |
1:8aa5cdb4ab67 | 89 | { |
| Jonathan Austin |
1:8aa5cdb4ab67 | 90 | if (period < 1) |
| Jonathan Austin |
1:8aa5cdb4ab67 | 91 | return MICROBIT_INVALID_PARAMETER; |
| Jonathan Austin |
1:8aa5cdb4ab67 | 92 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 93 | // If a timer is already running, ensure it is disabled before reconfiguring. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 94 | if (tick_period) |
| LancasterUniversity | 49:88f03f3feff1 | 95 | ticker->detach(); |
| Jonathan Austin |
1:8aa5cdb4ab67 | 96 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 97 | // register a period callback to drive the scheduler and any other registered components. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 98 | tick_period = period; |
| LancasterUniversity | 49:88f03f3feff1 | 99 | ticker->attach_us(system_timer_tick, period * 1000); |
| Jonathan Austin |
1:8aa5cdb4ab67 | 100 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 101 | return MICROBIT_OK; |
| Jonathan Austin |
1:8aa5cdb4ab67 | 102 | } |
| Jonathan Austin |
1:8aa5cdb4ab67 | 103 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 104 | /** |
| Jonathan Austin |
1:8aa5cdb4ab67 | 105 | * Accessor to obtain the current tick period in milliseconds |
| Jonathan Austin |
1:8aa5cdb4ab67 | 106 | * |
| Jonathan Austin |
1:8aa5cdb4ab67 | 107 | * @return the current tick period in milliseconds |
| Jonathan Austin |
1:8aa5cdb4ab67 | 108 | */ |
| Jonathan Austin |
1:8aa5cdb4ab67 | 109 | int system_timer_get_period() |
| Jonathan Austin |
1:8aa5cdb4ab67 | 110 | { |
| Jonathan Austin |
1:8aa5cdb4ab67 | 111 | return tick_period; |
| Jonathan Austin |
1:8aa5cdb4ab67 | 112 | } |
| Jonathan Austin |
1:8aa5cdb4ab67 | 113 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 114 | /** |
| LancasterUniversity | 49:88f03f3feff1 | 115 | * Updates the current time in microseconds, since power on. |
| LancasterUniversity | 49:88f03f3feff1 | 116 | * |
| LancasterUniversity | 49:88f03f3feff1 | 117 | * If the mbed Timer hasn't been initialised, it will be initialised |
| LancasterUniversity | 49:88f03f3feff1 | 118 | * on the first call to this function. |
| LancasterUniversity | 49:88f03f3feff1 | 119 | */ |
| LancasterUniversity | 49:88f03f3feff1 | 120 | void update_time() |
| LancasterUniversity | 49:88f03f3feff1 | 121 | { |
| LancasterUniversity | 49:88f03f3feff1 | 122 | // If we haven't been initialized, bring up the timer with the default period. |
| LancasterUniversity | 49:88f03f3feff1 | 123 | if (timer == NULL || ticker == NULL) |
| LancasterUniversity | 49:88f03f3feff1 | 124 | system_timer_init(SYSTEM_TICK_PERIOD_MS); |
| LancasterUniversity | 49:88f03f3feff1 | 125 | |
| LancasterUniversity | 49:88f03f3feff1 | 126 | time_us += timer->read_us(); |
| LancasterUniversity | 49:88f03f3feff1 | 127 | timer->reset(); |
| LancasterUniversity | 49:88f03f3feff1 | 128 | } |
| LancasterUniversity | 49:88f03f3feff1 | 129 | |
| LancasterUniversity | 49:88f03f3feff1 | 130 | /** |
| Jonathan Austin |
1:8aa5cdb4ab67 | 131 | * Determines the time since the device was powered on. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 132 | * |
| Jonathan Austin |
1:8aa5cdb4ab67 | 133 | * @return the current time since power on in milliseconds |
| Jonathan Austin |
1:8aa5cdb4ab67 | 134 | */ |
| LancasterUniversity | 49:88f03f3feff1 | 135 | uint64_t system_timer_current_time() |
| Jonathan Austin |
1:8aa5cdb4ab67 | 136 | { |
| LancasterUniversity | 49:88f03f3feff1 | 137 | return system_timer_current_time_us() / 1000; |
| LancasterUniversity | 49:88f03f3feff1 | 138 | } |
| LancasterUniversity | 49:88f03f3feff1 | 139 | |
| LancasterUniversity | 49:88f03f3feff1 | 140 | /** |
| LancasterUniversity | 49:88f03f3feff1 | 141 | * Determines the time since the device was powered on. |
| LancasterUniversity | 49:88f03f3feff1 | 142 | * |
| LancasterUniversity | 49:88f03f3feff1 | 143 | * @return the current time since power on in microseconds |
| LancasterUniversity | 49:88f03f3feff1 | 144 | */ |
| LancasterUniversity | 49:88f03f3feff1 | 145 | uint64_t system_timer_current_time_us() |
| LancasterUniversity | 49:88f03f3feff1 | 146 | { |
| LancasterUniversity | 49:88f03f3feff1 | 147 | update_time(); |
| LancasterUniversity | 49:88f03f3feff1 | 148 | return time_us; |
| Jonathan Austin |
1:8aa5cdb4ab67 | 149 | } |
| Jonathan Austin |
1:8aa5cdb4ab67 | 150 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 151 | /** |
| Jonathan Austin |
1:8aa5cdb4ab67 | 152 | * Timer callback. Called from interrupt context, once per period. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 153 | * |
| Jonathan Austin |
1:8aa5cdb4ab67 | 154 | * Simply checks to determine if any fibers blocked on the sleep queue need to be woken up |
| Jonathan Austin |
1:8aa5cdb4ab67 | 155 | * and made runnable. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 156 | */ |
| Jonathan Austin |
1:8aa5cdb4ab67 | 157 | void system_timer_tick() |
| Jonathan Austin |
1:8aa5cdb4ab67 | 158 | { |
| LancasterUniversity | 49:88f03f3feff1 | 159 | update_time(); |
| Jonathan Austin |
1:8aa5cdb4ab67 | 160 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 161 | // Update any components registered for a callback |
| Jonathan Austin |
1:8aa5cdb4ab67 | 162 | for(int i = 0; i < MICROBIT_SYSTEM_COMPONENTS; i++) |
| Jonathan Austin |
1:8aa5cdb4ab67 | 163 | if(systemTickComponents[i] != NULL) |
| Jonathan Austin |
1:8aa5cdb4ab67 | 164 | systemTickComponents[i]->systemTick(); |
| Jonathan Austin |
1:8aa5cdb4ab67 | 165 | } |
| Jonathan Austin |
1:8aa5cdb4ab67 | 166 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 167 | /** |
| Jonathan Austin |
1:8aa5cdb4ab67 | 168 | * Add a component to the array of system components. This component will then receive |
| Jonathan Austin |
1:8aa5cdb4ab67 | 169 | * periodic callbacks, once every tick period. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 170 | * |
| Jonathan Austin |
1:8aa5cdb4ab67 | 171 | * @param component The component to add. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 172 | * |
| Jonathan Austin |
1:8aa5cdb4ab67 | 173 | * @return MICROBIT_OK on success. MICROBIT_NO_RESOURCES is returned if the component array is full. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 174 | * |
| Jonathan Austin |
1:8aa5cdb4ab67 | 175 | * @note The callback will be in interrupt context. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 176 | */ |
| Jonathan Austin |
1:8aa5cdb4ab67 | 177 | int system_timer_add_component(MicroBitComponent *component) |
| Jonathan Austin |
1:8aa5cdb4ab67 | 178 | { |
| Jonathan Austin |
1:8aa5cdb4ab67 | 179 | int i = 0; |
| Jonathan Austin |
1:8aa5cdb4ab67 | 180 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 181 | // If we haven't been initialized, bring up the timer with the default period. |
| LancasterUniversity | 49:88f03f3feff1 | 182 | if (timer == NULL || ticker == NULL) |
| Jonathan Austin |
1:8aa5cdb4ab67 | 183 | system_timer_init(SYSTEM_TICK_PERIOD_MS); |
| Jonathan Austin |
1:8aa5cdb4ab67 | 184 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 185 | while(systemTickComponents[i] != NULL && i < MICROBIT_SYSTEM_COMPONENTS) |
| Jonathan Austin |
1:8aa5cdb4ab67 | 186 | i++; |
| Jonathan Austin |
1:8aa5cdb4ab67 | 187 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 188 | if(i == MICROBIT_SYSTEM_COMPONENTS) |
| Jonathan Austin |
1:8aa5cdb4ab67 | 189 | return MICROBIT_NO_RESOURCES; |
| Jonathan Austin |
1:8aa5cdb4ab67 | 190 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 191 | systemTickComponents[i] = component; |
| Jonathan Austin |
1:8aa5cdb4ab67 | 192 | return MICROBIT_OK; |
| Jonathan Austin |
1:8aa5cdb4ab67 | 193 | } |
| Jonathan Austin |
1:8aa5cdb4ab67 | 194 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 195 | /** |
| Jonathan Austin |
1:8aa5cdb4ab67 | 196 | * Remove a component from the array of system components. This component will no longer receive |
| Jonathan Austin |
1:8aa5cdb4ab67 | 197 | * periodic callbacks. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 198 | * |
| Jonathan Austin |
1:8aa5cdb4ab67 | 199 | * @param component The component to remove. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 200 | * |
| Jonathan Austin |
1:8aa5cdb4ab67 | 201 | * @return MICROBIT_OK on success. MICROBIT_INVALID_PARAMETER is returned if the given component has not been previously added. |
| Jonathan Austin |
1:8aa5cdb4ab67 | 202 | */ |
| Jonathan Austin |
1:8aa5cdb4ab67 | 203 | int system_timer_remove_component(MicroBitComponent *component) |
| Jonathan Austin |
1:8aa5cdb4ab67 | 204 | { |
| Jonathan Austin |
1:8aa5cdb4ab67 | 205 | int i = 0; |
| Jonathan Austin |
1:8aa5cdb4ab67 | 206 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 207 | while(systemTickComponents[i] != component && i < MICROBIT_SYSTEM_COMPONENTS) |
| Jonathan Austin |
1:8aa5cdb4ab67 | 208 | i++; |
| Jonathan Austin |
1:8aa5cdb4ab67 | 209 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 210 | if(i == MICROBIT_SYSTEM_COMPONENTS) |
| Jonathan Austin |
1:8aa5cdb4ab67 | 211 | return MICROBIT_INVALID_PARAMETER; |
| Jonathan Austin |
1:8aa5cdb4ab67 | 212 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 213 | systemTickComponents[i] = NULL; |
| Jonathan Austin |
1:8aa5cdb4ab67 | 214 | |
| Jonathan Austin |
1:8aa5cdb4ab67 | 215 | return MICROBIT_OK; |
| LancasterUniversity | 31:87789e55bac7 | 216 | } |