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

Committer:
LancasterUniversity
Date:
Wed Jul 13 12:52:54 2016 +0100
Revision:
641:be9b2017785a
Parent:
321:39f2bc1d0627 
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
mbed_official 36:ab3ee77451e7 1 /* mbed Microcontroller Library
mbed_official 36:ab3ee77451e7 2 * Copyright (c) 2006-2013 ARM Limited
mbed_official 36:ab3ee77451e7 3 *
mbed_official 36:ab3ee77451e7 4 * Licensed under the Apache License, Version 2.0 (the "License");
mbed_official 36:ab3ee77451e7 5 * you may not use this file except in compliance with the License.
mbed_official 36:ab3ee77451e7 6 * You may obtain a copy of the License at
mbed_official 36:ab3ee77451e7 7 *
mbed_official 36:ab3ee77451e7 8 * http://www.apache.org/licenses/LICENSE-2.0
mbed_official 36:ab3ee77451e7 9 *
mbed_official 36:ab3ee77451e7 10 * Unless required by applicable law or agreed to in writing, software
mbed_official 36:ab3ee77451e7 11 * distributed under the License is distributed on an "AS IS" BASIS,
mbed_official 36:ab3ee77451e7 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
mbed_official 36:ab3ee77451e7 13 * See the License for the specific language governing permissions and
mbed_official 36:ab3ee77451e7 14 * limitations under the License.
mbed_official 36:ab3ee77451e7 15 */
mbed_official 36:ab3ee77451e7 16 #include "RawSerial.h"
mbed_official 36:ab3ee77451e7 17 #include "wait_api.h"
mbed_official 64:7b352733b00a 18 #include <cstdarg>
mbed_official 36:ab3ee77451e7 19
mbed_official 36:ab3ee77451e7 20 #if DEVICE_SERIAL
mbed_official 36:ab3ee77451e7 21
mbed_official 64:7b352733b00a 22 #define STRING_STACK_LIMIT 120
mbed_official 64:7b352733b00a 23
mbed_official 36:ab3ee77451e7 24 namespace mbed {
mbed_official 36:ab3ee77451e7 25
mbed_official 36:ab3ee77451e7 26 RawSerial::RawSerial(PinName tx, PinName rx) : SerialBase(tx, rx) {
mbed_official 36:ab3ee77451e7 27 }
mbed_official 36:ab3ee77451e7 28
mbed_official 36:ab3ee77451e7 29 int RawSerial::getc() {
mbed_official 36:ab3ee77451e7 30 return _base_getc();
mbed_official 36:ab3ee77451e7 31 }
mbed_official 36:ab3ee77451e7 32
mbed_official 36:ab3ee77451e7 33 int RawSerial::putc(int c) {
mbed_official 36:ab3ee77451e7 34 return _base_putc(c);
mbed_official 36:ab3ee77451e7 35 }
mbed_official 36:ab3ee77451e7 36
mbed_official 64:7b352733b00a 37 int RawSerial::puts(const char *str) {
mbed_official 64:7b352733b00a 38 while (*str)
mbed_official 64:7b352733b00a 39 putc(*str ++);
mbed_official 64:7b352733b00a 40 return 0;
mbed_official 64:7b352733b00a 41 }
mbed_official 64:7b352733b00a 42
mbed_official 64:7b352733b00a 43 // Experimental support for printf in RawSerial. No Stream inheritance
mbed_official 64:7b352733b00a 44 // means we can't call printf() directly, so we use sprintf() instead.
mbed_official 64:7b352733b00a 45 // We only call malloc() for the sprintf() buffer if the buffer
mbed_official 64:7b352733b00a 46 // length is above a certain threshold, otherwise we use just the stack.
mbed_official 64:7b352733b00a 47 int RawSerial::printf(const char *format, ...) {
mbed_official 64:7b352733b00a 48 std::va_list arg;
mbed_official 64:7b352733b00a 49 va_start(arg, format);
mbed_official 64:7b352733b00a 50 int len = vsnprintf(NULL, 0, format, arg);
mbed_official 64:7b352733b00a 51 if (len < STRING_STACK_LIMIT) {
mbed_official 64:7b352733b00a 52 char temp[STRING_STACK_LIMIT];
mbed_official 64:7b352733b00a 53 vsprintf(temp, format, arg);
mbed_official 64:7b352733b00a 54 puts(temp);
mbed_official 64:7b352733b00a 55 } else {
mbed_official 64:7b352733b00a 56 char *temp = new char[len + 1];
mbed_official 64:7b352733b00a 57 vsprintf(temp, format, arg);
mbed_official 64:7b352733b00a 58 puts(temp);
mbed_official 64:7b352733b00a 59 delete[] temp;
mbed_official 64:7b352733b00a 60 }
mbed_official 64:7b352733b00a 61 va_end(arg);
mbed_official 64:7b352733b00a 62 return len;
mbed_official 64:7b352733b00a 63 }
mbed_official 64:7b352733b00a 64
mbed_official 36:ab3ee77451e7 65 } // namespace mbed
mbed_official 36:ab3ee77451e7 66
mbed_official 36:ab3ee77451e7 67 #endif