Lancaster University / mbed-src

Lancaster University's (short term!) clone of mbed-src for micro:bit. This is a copy of the github branch https://github.com/lancaster-university/mbed-classic

Fork of mbed-src by mbed official

common/InterruptIn.cpp@641:be9b2017785a, 2016-07-13 (annotated)

Committer:
LancasterUniversity
Date:
Wed Jul 13 12:52:54 2016 +0100
Revision:
641:be9b2017785a
Parent:
212:34d62c0b2af6 
Synchronized with git rev 1fb8ab4c

Author: James Devine

mbed-classic: BUGFIX for timer when using wait_ms from interrupt context



Previously if a user used wait[_ms,_us] in interrupt context the device would

hang indefinitely. This was due to incrementing overflowCount from

interrupt context only.



This meant that if a user used wait[_ms,_us] in an ISR with

the same or greater interrupt priority, it would result in an infinite

loop as the overflowCount variable would never be incremented, and

wait[_ms,_us] would never return.



This patch simply applies a better solution for the race condition

mentioned in the previous commit. It instead disables the timer1

interrupt and increments the overflowCount variable, preventing

the race condition whilst supporting wait[_ms,_us] in interrupt

context.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
bogdanm 13:0645d8841f51 1 /* mbed Microcontroller Library
bogdanm 13:0645d8841f51 2 * Copyright (c) 2006-2013 ARM Limited
bogdanm 13:0645d8841f51 3 *
bogdanm 13:0645d8841f51 4 * Licensed under the Apache License, Version 2.0 (the "License");
bogdanm 13:0645d8841f51 5 * you may not use this file except in compliance with the License.
bogdanm 13:0645d8841f51 6 * You may obtain a copy of the License at
bogdanm 13:0645d8841f51 7 *
bogdanm 13:0645d8841f51 8 * http://www.apache.org/licenses/LICENSE-2.0
bogdanm 13:0645d8841f51 9 *
bogdanm 13:0645d8841f51 10 * Unless required by applicable law or agreed to in writing, software
bogdanm 13:0645d8841f51 11 * distributed under the License is distributed on an "AS IS" BASIS,
bogdanm 13:0645d8841f51 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
bogdanm 13:0645d8841f51 13 * See the License for the specific language governing permissions and
bogdanm 13:0645d8841f51 14 * limitations under the License.
bogdanm 13:0645d8841f51 15 */
bogdanm 13:0645d8841f51 16 #include "InterruptIn.h"
bogdanm 13:0645d8841f51 17
bogdanm 13:0645d8841f51 18 #if DEVICE_INTERRUPTIN
bogdanm 13:0645d8841f51 19
bogdanm 13:0645d8841f51 20 namespace mbed {
bogdanm 13:0645d8841f51 21
mbed_official 212:34d62c0b2af6 22 InterruptIn::InterruptIn(PinName pin) : gpio(),
mbed_official 212:34d62c0b2af6 23 gpio_irq(),
mbed_official 212:34d62c0b2af6 24 _rise(),
mbed_official 212:34d62c0b2af6 25 _fall() {
bogdanm 13:0645d8841f51 26 gpio_irq_init(&gpio_irq, pin, (&InterruptIn::_irq_handler), (uint32_t)this);
mbed_official 113:65a335a675de 27 gpio_init_in(&gpio, pin);
bogdanm 13:0645d8841f51 28 }
bogdanm 13:0645d8841f51 29
bogdanm 13:0645d8841f51 30 InterruptIn::~InterruptIn() {
bogdanm 13:0645d8841f51 31 gpio_irq_free(&gpio_irq);
bogdanm 13:0645d8841f51 32 }
bogdanm 13:0645d8841f51 33
bogdanm 13:0645d8841f51 34 int InterruptIn::read() {
bogdanm 13:0645d8841f51 35 return gpio_read(&gpio);
bogdanm 13:0645d8841f51 36 }
bogdanm 13:0645d8841f51 37
bogdanm 13:0645d8841f51 38 void InterruptIn::mode(PinMode pull) {
bogdanm 13:0645d8841f51 39 gpio_mode(&gpio, pull);
bogdanm 13:0645d8841f51 40 }
bogdanm 13:0645d8841f51 41
mbed_official 36:ab3ee77451e7 42 void InterruptIn::rise(void (*fptr)(void)) {
bogdanm 13:0645d8841f51 43 if (fptr) {
mbed_official 36:ab3ee77451e7 44 _rise.attach(fptr);
bogdanm 13:0645d8841f51 45 gpio_irq_set(&gpio_irq, IRQ_RISE, 1);
bogdanm 13:0645d8841f51 46 } else {
bogdanm 13:0645d8841f51 47 gpio_irq_set(&gpio_irq, IRQ_RISE, 0);
bogdanm 13:0645d8841f51 48 }
bogdanm 13:0645d8841f51 49 }
bogdanm 13:0645d8841f51 50
mbed_official 36:ab3ee77451e7 51 void InterruptIn::fall(void (*fptr)(void)) {
bogdanm 13:0645d8841f51 52 if (fptr) {
mbed_official 36:ab3ee77451e7 53 _fall.attach(fptr);
bogdanm 13:0645d8841f51 54 gpio_irq_set(&gpio_irq, IRQ_FALL, 1);
bogdanm 13:0645d8841f51 55 } else {
bogdanm 13:0645d8841f51 56 gpio_irq_set(&gpio_irq, IRQ_FALL, 0);
bogdanm 13:0645d8841f51 57 }
bogdanm 13:0645d8841f51 58 }
bogdanm 13:0645d8841f51 59
bogdanm 13:0645d8841f51 60 void InterruptIn::_irq_handler(uint32_t id, gpio_irq_event event) {
bogdanm 13:0645d8841f51 61 InterruptIn *handler = (InterruptIn*)id;
bogdanm 13:0645d8841f51 62 switch (event) {
bogdanm 13:0645d8841f51 63 case IRQ_RISE: handler->_rise.call(); break;
bogdanm 13:0645d8841f51 64 case IRQ_FALL: handler->_fall.call(); break;
bogdanm 13:0645d8841f51 65 case IRQ_NONE: break;
bogdanm 13:0645d8841f51 66 }
bogdanm 13:0645d8841f51 67 }
bogdanm 13:0645d8841f51 68
mbed_official 35:371630885ad6 69 void InterruptIn::enable_irq() {
mbed_official 35:371630885ad6 70 gpio_irq_enable(&gpio_irq);
mbed_official 35:371630885ad6 71 }
mbed_official 35:371630885ad6 72
mbed_official 35:371630885ad6 73 void InterruptIn::disable_irq() {
mbed_official 35:371630885ad6 74 gpio_irq_disable(&gpio_irq);
mbed_official 35:371630885ad6 75 }
mbed_official 35:371630885ad6 76
bogdanm 13:0645d8841f51 77 #ifdef MBED_OPERATORS
bogdanm 13:0645d8841f51 78 InterruptIn::operator int() {
bogdanm 13:0645d8841f51 79 return read();
bogdanm 13:0645d8841f51 80 }
bogdanm 13:0645d8841f51 81 #endif
bogdanm 13:0645d8841f51 82
bogdanm 13:0645d8841f51 83 } // namespace mbed
bogdanm 13:0645d8841f51 84
bogdanm 13:0645d8841f51 85 #endif