Martin Cottrell / microbit-dal

No Changes

Dependencies:   BLE_API mbed-dev-bin nRF51822

Dependents:   microbit

Fork of microbit-dal by Lancaster University

source/core/MicroBitSystemTimer.cpp@35:8ce23bc1af38, 2016-07-13 (annotated)

Committer:
LancasterUniversity
Date:
Wed Jul 13 12:18:14 2016 +0100
Revision:
35:8ce23bc1af38
Parent:
32:ece16b5987dd
Child:
37:b624ae5e94a5
Synchronized with git rev 732971e7

Author: James Devine

microbit-dal: Added events to MicroBitPin



Added rise, fall, pulse HI and LO events.



The pulse Hi and LO event timestamp given in the MicroBitEvent is the

duration for which the input was HI or LO for.



eventOn(int eventType) is used to configure the events generated

from the pin instance.

Who changed what in which revision?

UserRevisionLine numberNew 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 35:8ce23bc1af38 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 35:8ce23bc1af38 52 static Ticker *ticker = NULL;
LancasterUniversity 35:8ce23bc1af38 53
LancasterUniversity 35:8ce23bc1af38 54 // System timer.
LancasterUniversity 35:8ce23bc1af38 55 static Timer *timer = NULL;
Jonathan Austin 1:8aa5cdb4ab67 56
Jonathan Austin 1:8aa5cdb4ab67 57
Jonathan Austin 1:8aa5cdb4ab67 58 /**
LancasterUniversity 35:8ce23bc1af38 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 35:8ce23bc1af38 69 if (ticker == NULL)
LancasterUniversity 35:8ce23bc1af38 70 ticker = new Ticker();
LancasterUniversity 35:8ce23bc1af38 71
Jonathan Austin 1:8aa5cdb4ab67 72 if (timer == NULL)
LancasterUniversity 35:8ce23bc1af38 73 {
LancasterUniversity 35:8ce23bc1af38 74 timer = new Timer();
LancasterUniversity 35:8ce23bc1af38 75 timer->start();
LancasterUniversity 35:8ce23bc1af38 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 35:8ce23bc1af38 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 35:8ce23bc1af38 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 35:8ce23bc1af38 115 * Updates the current time in microseconds, since power on.
LancasterUniversity 35:8ce23bc1af38 116 *
LancasterUniversity 35:8ce23bc1af38 117 * If the mbed Timer hasn't been initialised, it will be initialised
LancasterUniversity 35:8ce23bc1af38 118 * on the first call to this function.
LancasterUniversity 35:8ce23bc1af38 119 */
LancasterUniversity 35:8ce23bc1af38 120 void update_time()
LancasterUniversity 35:8ce23bc1af38 121 {
LancasterUniversity 35:8ce23bc1af38 122 // If we haven't been initialized, bring up the timer with the default period.
LancasterUniversity 35:8ce23bc1af38 123 if (timer == NULL || ticker == NULL)
LancasterUniversity 35:8ce23bc1af38 124 system_timer_init(SYSTEM_TICK_PERIOD_MS);
LancasterUniversity 35:8ce23bc1af38 125
LancasterUniversity 35:8ce23bc1af38 126 time_us += timer->read_us();
LancasterUniversity 35:8ce23bc1af38 127 timer->reset();
LancasterUniversity 35:8ce23bc1af38 128 }
LancasterUniversity 35:8ce23bc1af38 129
LancasterUniversity 35:8ce23bc1af38 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 35:8ce23bc1af38 135 uint64_t system_timer_current_time()
Jonathan Austin 1:8aa5cdb4ab67 136 {
LancasterUniversity 35:8ce23bc1af38 137 return system_timer_current_time_us() / 1000;
LancasterUniversity 35:8ce23bc1af38 138 }
LancasterUniversity 35:8ce23bc1af38 139
LancasterUniversity 35:8ce23bc1af38 140 /**
LancasterUniversity 35:8ce23bc1af38 141 * Determines the time since the device was powered on.
LancasterUniversity 35:8ce23bc1af38 142 *
LancasterUniversity 35:8ce23bc1af38 143 * @return the current time since power on in microseconds
LancasterUniversity 35:8ce23bc1af38 144 */
LancasterUniversity 35:8ce23bc1af38 145 uint64_t system_timer_current_time_us()
LancasterUniversity 35:8ce23bc1af38 146 {
LancasterUniversity 35:8ce23bc1af38 147 update_time();
LancasterUniversity 35:8ce23bc1af38 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 35:8ce23bc1af38 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 35:8ce23bc1af38 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 }