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/I2CSlave.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 "I2CSlave.h"
bogdanm 13:0645d8841f51 17
bogdanm 13:0645d8841f51 18 #if DEVICE_I2CSLAVE
bogdanm 13:0645d8841f51 19
bogdanm 13:0645d8841f51 20 namespace mbed {
bogdanm 13:0645d8841f51 21
mbed_official 212:34d62c0b2af6 22 I2CSlave::I2CSlave(PinName sda, PinName scl) : _i2c() {
bogdanm 13:0645d8841f51 23 i2c_init(&_i2c, sda, scl);
bogdanm 13:0645d8841f51 24 i2c_frequency(&_i2c, 100000);
bogdanm 13:0645d8841f51 25 i2c_slave_mode(&_i2c, 1);
bogdanm 13:0645d8841f51 26 }
bogdanm 13:0645d8841f51 27
bogdanm 13:0645d8841f51 28 void I2CSlave::frequency(int hz) {
bogdanm 13:0645d8841f51 29 i2c_frequency(&_i2c, hz);
bogdanm 13:0645d8841f51 30 }
bogdanm 13:0645d8841f51 31
bogdanm 13:0645d8841f51 32 void I2CSlave::address(int address) {
bogdanm 13:0645d8841f51 33 int addr = (address & 0xFF) | 1;
bogdanm 13:0645d8841f51 34 i2c_slave_address(&_i2c, 0, addr, 0);
bogdanm 13:0645d8841f51 35 }
bogdanm 13:0645d8841f51 36
bogdanm 13:0645d8841f51 37 int I2CSlave::receive(void) {
bogdanm 13:0645d8841f51 38 return i2c_slave_receive(&_i2c);
bogdanm 13:0645d8841f51 39 }
bogdanm 13:0645d8841f51 40
bogdanm 13:0645d8841f51 41 int I2CSlave::read(char *data, int length) {
bogdanm 13:0645d8841f51 42 return i2c_slave_read(&_i2c, data, length) != length;
bogdanm 13:0645d8841f51 43 }
bogdanm 13:0645d8841f51 44
bogdanm 13:0645d8841f51 45 int I2CSlave::read(void) {
bogdanm 13:0645d8841f51 46 return i2c_byte_read(&_i2c, 0);
bogdanm 13:0645d8841f51 47 }
bogdanm 13:0645d8841f51 48
bogdanm 13:0645d8841f51 49 int I2CSlave::write(const char *data, int length) {
bogdanm 13:0645d8841f51 50 return i2c_slave_write(&_i2c, data, length) != length;
bogdanm 13:0645d8841f51 51 }
bogdanm 13:0645d8841f51 52
bogdanm 13:0645d8841f51 53 int I2CSlave::write(int data) {
bogdanm 13:0645d8841f51 54 return i2c_byte_write(&_i2c, data);
bogdanm 13:0645d8841f51 55 }
bogdanm 13:0645d8841f51 56
bogdanm 13:0645d8841f51 57 void I2CSlave::stop(void) {
bogdanm 13:0645d8841f51 58 i2c_stop(&_i2c);
bogdanm 13:0645d8841f51 59 }
bogdanm 13:0645d8841f51 60
bogdanm 13:0645d8841f51 61 }
bogdanm 13:0645d8841f51 62
bogdanm 13:0645d8841f51 63 #endif