mbed library sources
Dependents: frdm_kl05z_gpio_test
Fork of mbed-src by
targets/hal/TARGET_STM/TARGET_NUCLEO_F103RB/us_ticker.c
- Committer:
- mbed_official
- Date:
- 2014-02-13
- Revision:
- 91:0a39e62a0464
- Parent:
- 87:085cde657901
- Child:
- 92:05f19f05c134
File content as of revision 91:0a39e62a0464:
/* 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 TIM1 #define TIM_MST_UP_IRQ TIM1_UP_IRQn #define TIM_MST_OC_IRQ TIM1_CC_IRQn #define TIM_MST_RCC RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE) static int us_ticker_inited = 0; static uint32_t SlaveCounter = 0; static uint32_t oc_int_part = 0; static 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); } // Used to increment the slave counter static void tim_update_irq_handler(void) { SlaveCounter++; if (TIM_GetITStatus(TIM_MST, TIM_IT_Update) == SET) { TIM_ClearITPendingBit(TIM_MST, TIM_IT_Update); } } // Used by interrupt system static void tim_oc_irq_handler(void) { uint16_t cval = TIM_MST->CNT; // Clear interrupt flag 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 µs 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 NVIC_SetVector(TIM_MST_UP_IRQ, (uint32_t)tim_update_irq_handler); NVIC_EnableIRQ(TIM_MST_UP_IRQ); // Output compare interrupt used for timeout feature NVIC_SetVector(TIM_MST_OC_IRQ, (uint32_t)tim_oc_irq_handler); NVIC_EnableIRQ(TIM_MST_OC_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(unsigned int timestamp) { int delta = (int)(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) { if (TIM_GetITStatus(TIM_MST, TIM_IT_CC1) == SET) { TIM_ClearITPendingBit(TIM_MST, TIM_IT_CC1); } }