mbed library sources
Dependents: Encrypted my_mbed lklk CyaSSL_DTLS_Cellular ... more
Superseded
This library was superseded by mbed-dev - https://os.mbed.com/users/mbed_official/code/mbed-dev/.
Development branch of the mbed library sources. This library is kept in synch with the latest changes from the mbed SDK and it is not guaranteed to work.
If you are looking for a stable and tested release, please import one of the official mbed library releases:
Import librarymbed
The official Mbed 2 C/C++ SDK provides the software platform and libraries to build your applications.
targets/hal/TARGET_STM/TARGET_NUCLEO_F103RB/us_ticker.c
- Committer:
- mbed_official
- Date:
- 2014-11-07
- Revision:
- 393:17d2d502961d
- Parent:
- 304:89b9c3a9a045
- Child:
- 402:09075a3b15e3
File content as of revision 393:17d2d502961d:
/* mbed Microcontroller Library * Copyright (c) 2014, STMicroelectronics * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * 3. Neither the name of STMicroelectronics nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include <stddef.h> #include "us_ticker_api.h" #include "PeripheralNames.h" // Timer selection: #define TIM_MST TIM4 #define TIM_MST_IRQ TIM4_IRQn #define TIM_MST_RCC RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE) static int us_ticker_inited = 0; static volatile uint32_t SlaveCounter = 0; static volatile uint32_t oc_int_part = 0; static volatile uint16_t oc_rem_part = 0; void set_compare(uint16_t count) { // Set new output compare value TIM_SetCompare1(TIM_MST, count); // Enable IT TIM_ITConfig(TIM_MST, TIM_IT_CC1, ENABLE); } static void tim_irq_handler(void) { uint16_t cval = TIM_MST->CNT; if (TIM_GetITStatus(TIM_MST, TIM_IT_Update) == SET) { TIM_ClearITPendingBit(TIM_MST, TIM_IT_Update); SlaveCounter++; } if (TIM_GetITStatus(TIM_MST, TIM_IT_CC1) == SET) { TIM_ClearITPendingBit(TIM_MST, TIM_IT_CC1); if (oc_rem_part > 0) { set_compare(oc_rem_part); // Finish the remaining time left oc_rem_part = 0; } else { if (oc_int_part > 0) { set_compare(0xFFFF); oc_rem_part = cval; // To finish the counter loop the next time oc_int_part--; } else { us_ticker_irq_handler(); } } } } void us_ticker_init(void) { TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; if (us_ticker_inited) return; us_ticker_inited = 1; // Enable timer clock TIM_MST_RCC; // Configure time base TIM_TimeBaseStructInit(&TIM_TimeBaseStructure); TIM_TimeBaseStructure.TIM_Period = 0xFFFF; TIM_TimeBaseStructure.TIM_Prescaler = (uint16_t)(SystemCoreClock / 1000000) - 1; // 1 �s tick TIM_TimeBaseStructure.TIM_ClockDivision = 0; TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; TIM_TimeBaseInit(TIM_MST, &TIM_TimeBaseStructure); // Configure interrupts TIM_ITConfig(TIM_MST, TIM_IT_Update, ENABLE); // Update interrupt used for 32-bit counter // Output compare interrupt used for timeout feature NVIC_SetVector(TIM_MST_IRQ, (uint32_t)tim_irq_handler); NVIC_EnableIRQ(TIM_MST_IRQ); // Enable timer TIM_Cmd(TIM_MST, ENABLE); } uint32_t us_ticker_read() { uint32_t counter, counter2; if (!us_ticker_inited) us_ticker_init(); // A situation might appear when Master overflows right after Slave is read and before the // new (overflowed) value of Master is read. Which would make the code below consider the // previous (incorrect) value of Slave and the new value of Master, which would return a // value in the past. Avoid this by computing consecutive values of the timer until they // are properly ordered. counter = (uint32_t)(SlaveCounter << 16); counter += TIM_MST->CNT; while (1) { counter2 = (uint32_t)(SlaveCounter << 16); counter2 += TIM_MST->CNT; if (counter2 > counter) { break; } counter = counter2; } return counter2; } void us_ticker_set_interrupt(timestamp_t timestamp) { int delta = (int)((uint32_t)timestamp - us_ticker_read()); uint16_t cval = TIM_MST->CNT; if (delta <= 0) { // This event was in the past us_ticker_irq_handler(); } else { oc_int_part = (uint32_t)(delta >> 16); oc_rem_part = (uint16_t)(delta & 0xFFFF); if (oc_rem_part <= (0xFFFF - cval)) { set_compare(cval + oc_rem_part); oc_rem_part = 0; } else { set_compare(0xFFFF); oc_rem_part = oc_rem_part - (0xFFFF - cval); } } } void us_ticker_disable_interrupt(void) { TIM_ITConfig(TIM_MST, TIM_IT_CC1, DISABLE); } void us_ticker_clear_interrupt(void) { TIM_ClearITPendingBit(TIM_MST, TIM_IT_CC1); }