tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_Freescale/TARGET_KPSDK_MCUS/us_ticker.c

   1 /* mbed Microcontroller Library
   2  * Copyright (c) 2006-2013 ARM Limited
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 #include <stddef.h>
  17 #include "us_ticker_api.h"
  18 #include "PeripheralNames.h"
  19 #include "fsl_pit_hal.h"
  20 #include "fsl_sim_hal.h"
  21 #include "fsl_clock_manager.h"
  22
  23 static int us_ticker_inited = 0;
  24
  25 void us_ticker_init(void) {
  26     if (us_ticker_inited) {
  27         return;
  28     }
  29     us_ticker_inited = 1;
  30
  31     //Common for ticker/timer
  32     uint32_t busClock;
  33     CLOCK_SYS_EnablePitClock(0);
  34     PIT_HAL_Enable(PIT_BASE);
  35     CLOCK_SYS_GetFreq(kBusClock, &busClock);
  36
  37     //Timer
  38     PIT_HAL_SetTimerPeriodByCount(PIT_BASE, 0, busClock / 1000000 - 1);
  39     PIT_HAL_SetTimerPeriodByCount(PIT_BASE, 1, 0xFFFFFFFF);
  40     PIT_HAL_SetTimerChainCmd(PIT_BASE, 1, true);
  41     PIT_HAL_StartTimer(PIT_BASE, 0);
  42     PIT_HAL_StartTimer(PIT_BASE, 1);
  43
  44     //Ticker
  45     PIT_HAL_SetTimerPeriodByCount(PIT_BASE, 2, busClock / 1000000 - 1);
  46     PIT_HAL_SetTimerChainCmd(PIT_BASE, 3, true);
  47     NVIC_SetVector(PIT3_IRQn, (uint32_t)us_ticker_irq_handler);
  48     NVIC_EnableIRQ(PIT3_IRQn);
  49 }
  50
  51
  52 uint32_t us_ticker_read() {
  53     if (!us_ticker_inited) {
  54         us_ticker_init();
  55     }
  56
  57     return ~(PIT_HAL_ReadTimerCount(PIT_BASE, 1));
  58 }
  59
  60 void us_ticker_disable_interrupt(void) {
  61     PIT_HAL_SetIntCmd(PIT_BASE, 3, false);
  62 }
  63
  64 void us_ticker_clear_interrupt(void) {
  65     PIT_HAL_ClearIntFlag(PIT_BASE, 3);
  66 }
  67
  68 void us_ticker_set_interrupt(timestamp_t timestamp) {
  69     int delta = (int)(timestamp - us_ticker_read());
  70     if (delta <= 0) {
  71         // This event was in the past:
  72         us_ticker_irq_handler();
  73         return;
  74     }
  75
  76     PIT_HAL_StopTimer(PIT_BASE, 3);
  77     PIT_HAL_StopTimer(PIT_BASE, 2);
  78     PIT_HAL_SetTimerPeriodByCount(PIT_BASE, 3, (uint32_t)delta);
  79     PIT_HAL_SetIntCmd(PIT_BASE, 3, true);
  80     PIT_HAL_StartTimer(PIT_BASE, 3);
  81     PIT_HAL_StartTimer(PIT_BASE, 2);
  82 }