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

Committer:
LancasterUniversity
Date:
Wed Jul 13 12:52:54 2016 +0100
Revision:
641:be9b2017785a
Parent:
457:777fdfed0738 
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 "BusOut.h"
mbed_official 457:777fdfed0738 17 #include "mbed_assert.h"
bogdanm 13:0645d8841f51 18
bogdanm 13:0645d8841f51 19 namespace mbed {
bogdanm 13:0645d8841f51 20
bogdanm 13:0645d8841f51 21 BusOut::BusOut(PinName p0, PinName p1, PinName p2, PinName p3, PinName p4, PinName p5, PinName p6, PinName p7, PinName p8, PinName p9, PinName p10, PinName p11, PinName p12, PinName p13, PinName p14, PinName p15) {
bogdanm 13:0645d8841f51 22 PinName pins[16] = {p0, p1, p2, p3, p4, p5, p6, p7, p8, p9, p10, p11, p12, p13, p14, p15};
bogdanm 13:0645d8841f51 23
mbed_official 455:8bc3a354916d 24 _nc_mask = 0;
bogdanm 13:0645d8841f51 25 for (int i=0; i<16; i++) {
bogdanm 13:0645d8841f51 26 _pin[i] = (pins[i] != NC) ? new DigitalOut(pins[i]) : 0;
mbed_official 455:8bc3a354916d 27 if (pins[i] != NC) {
mbed_official 455:8bc3a354916d 28 _nc_mask |= (1 << i);
mbed_official 455:8bc3a354916d 29 }
bogdanm 13:0645d8841f51 30 }
bogdanm 13:0645d8841f51 31 }
bogdanm 13:0645d8841f51 32
bogdanm 13:0645d8841f51 33 BusOut::BusOut(PinName pins[16]) {
mbed_official 455:8bc3a354916d 34 _nc_mask = 0;
bogdanm 13:0645d8841f51 35 for (int i=0; i<16; i++) {
bogdanm 13:0645d8841f51 36 _pin[i] = (pins[i] != NC) ? new DigitalOut(pins[i]) : 0;
mbed_official 455:8bc3a354916d 37 if (pins[i] != NC) {
mbed_official 455:8bc3a354916d 38 _nc_mask |= (1 << i);
mbed_official 455:8bc3a354916d 39 }
bogdanm 13:0645d8841f51 40 }
bogdanm 13:0645d8841f51 41 }
bogdanm 13:0645d8841f51 42
bogdanm 13:0645d8841f51 43 BusOut::~BusOut() {
bogdanm 13:0645d8841f51 44 for (int i=0; i<16; i++) {
bogdanm 13:0645d8841f51 45 if (_pin[i] != 0) {
bogdanm 13:0645d8841f51 46 delete _pin[i];
bogdanm 13:0645d8841f51 47 }
bogdanm 13:0645d8841f51 48 }
bogdanm 13:0645d8841f51 49 }
bogdanm 13:0645d8841f51 50
bogdanm 13:0645d8841f51 51 void BusOut::write(int value) {
bogdanm 13:0645d8841f51 52 for (int i=0; i<16; i++) {
bogdanm 13:0645d8841f51 53 if (_pin[i] != 0) {
bogdanm 13:0645d8841f51 54 _pin[i]->write((value >> i) & 1);
bogdanm 13:0645d8841f51 55 }
bogdanm 13:0645d8841f51 56 }
bogdanm 13:0645d8841f51 57 }
bogdanm 13:0645d8841f51 58
bogdanm 13:0645d8841f51 59 int BusOut::read() {
bogdanm 13:0645d8841f51 60 int v = 0;
bogdanm 13:0645d8841f51 61 for (int i=0; i<16; i++) {
bogdanm 13:0645d8841f51 62 if (_pin[i] != 0) {
bogdanm 13:0645d8841f51 63 v |= _pin[i]->read() << i;
bogdanm 13:0645d8841f51 64 }
bogdanm 13:0645d8841f51 65 }
bogdanm 13:0645d8841f51 66 return v;
bogdanm 13:0645d8841f51 67 }
bogdanm 13:0645d8841f51 68
bogdanm 13:0645d8841f51 69 #ifdef MBED_OPERATORS
bogdanm 13:0645d8841f51 70 BusOut& BusOut::operator= (int v) {
bogdanm 13:0645d8841f51 71 write(v);
bogdanm 13:0645d8841f51 72 return *this;
bogdanm 13:0645d8841f51 73 }
bogdanm 13:0645d8841f51 74
bogdanm 13:0645d8841f51 75 BusOut& BusOut::operator= (BusOut& rhs) {
bogdanm 13:0645d8841f51 76 write(rhs.read());
bogdanm 13:0645d8841f51 77 return *this;
bogdanm 13:0645d8841f51 78 }
bogdanm 13:0645d8841f51 79
mbed_official 455:8bc3a354916d 80 DigitalOut& BusOut::operator[] (int index) {
mbed_official 455:8bc3a354916d 81 MBED_ASSERT(index >= 0 && index <= 16);
mbed_official 455:8bc3a354916d 82 MBED_ASSERT(_pin[index]);
mbed_official 455:8bc3a354916d 83 return *_pin[index];
mbed_official 455:8bc3a354916d 84 }
mbed_official 455:8bc3a354916d 85
bogdanm 13:0645d8841f51 86 BusOut::operator int() {
bogdanm 13:0645d8841f51 87 return read();
bogdanm 13:0645d8841f51 88 }
bogdanm 13:0645d8841f51 89 #endif
bogdanm 13:0645d8841f51 90
bogdanm 13:0645d8841f51 91 } // namespace mbed