mbed library sources
Dependents: frdm_kl05z_gpio_test
Fork of mbed-src by
targets/hal/TARGET_Freescale/TARGET_KSDK_MCUS/TARGET_K64F/us_ticker.c
- Committer:
- mbed_official
- Date:
- 2014-04-02
- Revision:
- 146:f64d43ff0c18
File content as of revision 146:f64d43ff0c18:
/* mbed Microcontroller Library * Copyright (c) 2006-2013 ARM Limited * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include <stddef.h> #include "us_ticker_api.h" #include "PeripheralNames.h" #include "fsl_pit_hal.h" #include "fsl_sim_hal.h" #include "fsl_clock_manager.h" #include "fsl_clock_configs.h" static void pit_init(void); static void lptmr_init(void); static int us_ticker_inited = 0; void us_ticker_init(void) { if (us_ticker_inited) { return; } us_ticker_inited = 1; pit_init(); lptmr_init(); } uint32_t us_ticker_read() { if (!us_ticker_inited) { us_ticker_init(); } return ~(pit_hal_read_timer_count(1)); } /****************************************************************************** * Timer for us timing. ******************************************************************************/ static void pit_init(void) { uint32_t busClock; clock_hal_set_gate(kSimClockModulePIT, 0, true); pit_hal_enable(); clock_manager_get_frequency(kBusClock, &busClock); pit_hal_set_timer_period_count(0, busClock / 1000000 - 1); pit_hal_set_timer_period_count(1, 0xFFFFFFFF); pit_hal_configure_timer_chain(1, true); pit_hal_timer_start(0); pit_hal_timer_start(1); } /****************************************************************************** * Timer Event * * It schedules interrupts at given (32bit)us interval of time. * It is implemented used the 16bit Low Power Timer that remains powered in all * power modes. ******************************************************************************/ static void lptmr_isr(void); static void lptmr_init(void) { clock_hal_set_gate(kSimClockModuleLPTIMER, 0, true); /* Set interrupt handler */ NVIC_SetVector(LPTimer_IRQn, (uint32_t)lptmr_isr); NVIC_EnableIRQ(LPTimer_IRQn); /* TODO: check clock manager, due to nonstandard 50 MHz */ //No suitable external oscillator clock -> Use fast internal oscillator (4MHz / divider) MCG->C1 |= MCG_C1_IRCLKEN_MASK; MCG->C2 |= MCG_C2_IRCS_MASK; LPTMR0->PSR = LPTMR_PSR_PCS(0); switch (MCG->SC & MCG_SC_FCRDIV_MASK) { case MCG_SC_FCRDIV(0): //4MHz LPTMR0->PSR |= LPTMR_PSR_PRESCALE(1); break; case MCG_SC_FCRDIV(1): //2MHz LPTMR0->PSR |= LPTMR_PSR_PRESCALE(0); break; default: //1MHz or anything else, in which case we put it on 1MHz MCG->SC &= ~MCG_SC_FCRDIV_MASK; MCG->SC |= MCG_SC_FCRDIV(2); LPTMR0->PSR |= LPTMR_PSR_PBYP_MASK; } } void us_ticker_disable_interrupt(void) { BW_LPTMR_CSR_TIE(0); } void us_ticker_clear_interrupt(void) { // we already clear interrupt in lptmr_isr } static uint32_t us_ticker_int_counter = 0; static uint16_t us_ticker_int_remainder = 0; static void lptmr_set(unsigned short count) { HW_LPTMR_CSR_WR(0); BW_LPTMR_CMR_COMPARE(count); BW_LPTMR_CSR_TIE(1); BW_LPTMR_CSR_TEN(1); } static void lptmr_isr(void) { // write 1 to TCF to clear the LPT timer compare flag BW_LPTMR_CSR_TCF(1); if (us_ticker_int_counter > 0) { lptmr_set(0xFFFF); us_ticker_int_counter--; } else { if (us_ticker_int_remainder > 0) { lptmr_set(us_ticker_int_remainder); us_ticker_int_remainder = 0; } else { // This function is going to disable the interrupts if there are // no other events in the queue us_ticker_irq_handler(); } } } void us_ticker_set_interrupt(unsigned int timestamp) { int delta = (int)(timestamp - us_ticker_read()); if (delta <= 0) { // This event was in the past: us_ticker_irq_handler(); return; } us_ticker_int_counter = (uint32_t)(delta >> 16); us_ticker_int_remainder = (uint16_t)(0xFFFF & delta); if (us_ticker_int_counter > 0) { lptmr_set(0xFFFF); us_ticker_int_counter--; } else { lptmr_set(us_ticker_int_remainder); us_ticker_int_remainder = 0; } }