Johannes Stratmann / mbed-dev

added prescaler for 16 bit pwm in LPC1347 target

Fork of mbed-dev by mbed official

targets/hal/TARGET_Freescale/TARGET_KSDK2_MCUS/TARGET_KL27Z/us_ticker.c@121:7f86b4238bec, 2016-05-03 (annotated)

Committer:
mbed_official
Date:
Tue May 03 00:15:16 2016 +0100
Revision:
121:7f86b4238bec
Synchronized with git revision 9cef243de23875778f461bbe9a8c1bc47e65212b



Full URL: https://github.com/mbedmicro/mbed/commit/9cef243de23875778f461bbe9a8c1bc47e65212b/



Switch to KSDK 2.0

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 121:7f86b4238bec 1 /* mbed Microcontroller Library
mbed_official 121:7f86b4238bec 2 * Copyright (c) 2006-2013 ARM Limited
mbed_official 121:7f86b4238bec 3 *
mbed_official 121:7f86b4238bec 4 * Licensed under the Apache License, Version 2.0 (the "License");
mbed_official 121:7f86b4238bec 5 * you may not use this file except in compliance with the License.
mbed_official 121:7f86b4238bec 6 * You may obtain a copy of the License at
mbed_official 121:7f86b4238bec 7 *
mbed_official 121:7f86b4238bec 8 * http://www.apache.org/licenses/LICENSE-2.0
mbed_official 121:7f86b4238bec 9 *
mbed_official 121:7f86b4238bec 10 * Unless required by applicable law or agreed to in writing, software
mbed_official 121:7f86b4238bec 11 * distributed under the License is distributed on an "AS IS" BASIS,
mbed_official 121:7f86b4238bec 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
mbed_official 121:7f86b4238bec 13 * See the License for the specific language governing permissions and
mbed_official 121:7f86b4238bec 14 * limitations under the License.
mbed_official 121:7f86b4238bec 15 */
mbed_official 121:7f86b4238bec 16 #include <stddef.h>
mbed_official 121:7f86b4238bec 17 #include "us_ticker_api.h"
mbed_official 121:7f86b4238bec 18 #include "PeripheralNames.h"
mbed_official 121:7f86b4238bec 19 #include "fsl_pit.h"
mbed_official 121:7f86b4238bec 20 #include "fsl_lptmr.h"
mbed_official 121:7f86b4238bec 21 #include "fsl_clock_config.h"
mbed_official 121:7f86b4238bec 22
mbed_official 121:7f86b4238bec 23 static int us_ticker_inited = 0;
mbed_official 121:7f86b4238bec 24
mbed_official 121:7f86b4238bec 25 void us_ticker_init(void) {
mbed_official 121:7f86b4238bec 26 if (us_ticker_inited) {
mbed_official 121:7f86b4238bec 27 return;
mbed_official 121:7f86b4238bec 28 }
mbed_official 121:7f86b4238bec 29 us_ticker_inited = 1;
mbed_official 121:7f86b4238bec 30
mbed_official 121:7f86b4238bec 31 // Need to initialize the clocks here as ticker init gets called before mbed_sdk_init
mbed_official 121:7f86b4238bec 32 if (SystemCoreClock == DEFAULT_SYSTEM_CLOCK)
mbed_official 121:7f86b4238bec 33 BOARD_BootClockRUN();
mbed_official 121:7f86b4238bec 34
mbed_official 121:7f86b4238bec 35 //Timer uses PIT
mbed_official 121:7f86b4238bec 36 //Common for ticker/timer
mbed_official 121:7f86b4238bec 37 uint32_t busClock;
mbed_official 121:7f86b4238bec 38
mbed_official 121:7f86b4238bec 39 // Structure to initialize PIT
mbed_official 121:7f86b4238bec 40 pit_config_t pitConfig;
mbed_official 121:7f86b4238bec 41
mbed_official 121:7f86b4238bec 42 PIT_GetDefaultConfig(&pitConfig);
mbed_official 121:7f86b4238bec 43 PIT_Init(PIT, &pitConfig);
mbed_official 121:7f86b4238bec 44
mbed_official 121:7f86b4238bec 45 busClock = CLOCK_GetFreq(kCLOCK_BusClk);
mbed_official 121:7f86b4238bec 46
mbed_official 121:7f86b4238bec 47 PIT_SetTimerPeriod(PIT, kPIT_Chnl_0, busClock / 1000000 - 1);
mbed_official 121:7f86b4238bec 48 PIT_SetTimerPeriod(PIT, kPIT_Chnl_1, 0xFFFFFFFF);
mbed_official 121:7f86b4238bec 49 PIT_SetTimerChainMode(PIT, kPIT_Chnl_1, true);
mbed_official 121:7f86b4238bec 50 PIT_StartTimer(PIT, kPIT_Chnl_0);
mbed_official 121:7f86b4238bec 51 PIT_StartTimer(PIT, kPIT_Chnl_1);
mbed_official 121:7f86b4238bec 52
mbed_official 121:7f86b4238bec 53 //Ticker uses LPTMR
mbed_official 121:7f86b4238bec 54 lptmr_config_t lptmrConfig;
mbed_official 121:7f86b4238bec 55 LPTMR_GetDefaultConfig(&lptmrConfig);
mbed_official 121:7f86b4238bec 56 lptmrConfig.prescalerClockSource = kLPTMR_PrescalerClock_0;
mbed_official 121:7f86b4238bec 57 LPTMR_Init(LPTMR0, &lptmrConfig);
mbed_official 121:7f86b4238bec 58
mbed_official 121:7f86b4238bec 59 busClock = CLOCK_GetFreq(kCLOCK_McgInternalRefClk);
mbed_official 121:7f86b4238bec 60 LPTMR_SetTimerPeriod(LPTMR0, busClock / 1000000 - 1);
mbed_official 121:7f86b4238bec 61 /* Set interrupt handler */
mbed_official 121:7f86b4238bec 62 NVIC_SetVector(LPTMR0_IRQn, (uint32_t)us_ticker_irq_handler);
mbed_official 121:7f86b4238bec 63 NVIC_EnableIRQ(LPTMR0_IRQn);
mbed_official 121:7f86b4238bec 64 }
mbed_official 121:7f86b4238bec 65
mbed_official 121:7f86b4238bec 66
mbed_official 121:7f86b4238bec 67 uint32_t us_ticker_read() {
mbed_official 121:7f86b4238bec 68 if (!us_ticker_inited) {
mbed_official 121:7f86b4238bec 69 us_ticker_init();
mbed_official 121:7f86b4238bec 70 }
mbed_official 121:7f86b4238bec 71
mbed_official 121:7f86b4238bec 72 return ~(PIT_GetCurrentTimerCount(PIT, kPIT_Chnl_1));
mbed_official 121:7f86b4238bec 73 }
mbed_official 121:7f86b4238bec 74
mbed_official 121:7f86b4238bec 75 void us_ticker_disable_interrupt(void) {
mbed_official 121:7f86b4238bec 76 LPTMR_DisableInterrupts(LPTMR0, kLPTMR_TimerInterruptEnable);
mbed_official 121:7f86b4238bec 77 }
mbed_official 121:7f86b4238bec 78
mbed_official 121:7f86b4238bec 79 void us_ticker_clear_interrupt(void) {
mbed_official 121:7f86b4238bec 80 LPTMR_ClearStatusFlags(LPTMR0, kLPTMR_TimerCompareFlag);
mbed_official 121:7f86b4238bec 81 }
mbed_official 121:7f86b4238bec 82
mbed_official 121:7f86b4238bec 83 void us_ticker_set_interrupt(timestamp_t timestamp) {
mbed_official 121:7f86b4238bec 84 int delta = (int)(timestamp - us_ticker_read());
mbed_official 121:7f86b4238bec 85 if (delta <= 0) {
mbed_official 121:7f86b4238bec 86 // This event was in the past.
mbed_official 121:7f86b4238bec 87 // Set the interrupt as pending, but don't process it here.
mbed_official 121:7f86b4238bec 88 // This prevents a recurive loop under heavy load
mbed_official 121:7f86b4238bec 89 // which can lead to a stack overflow.
mbed_official 121:7f86b4238bec 90 NVIC_SetPendingIRQ(LPTMR0_IRQn);
mbed_official 121:7f86b4238bec 91 return;
mbed_official 121:7f86b4238bec 92 }
mbed_official 121:7f86b4238bec 93
mbed_official 121:7f86b4238bec 94 LPTMR_StopTimer(LPTMR0);
mbed_official 121:7f86b4238bec 95 LPTMR_SetTimerPeriod(LPTMR0, (uint32_t)delta);
mbed_official 121:7f86b4238bec 96 LPTMR_EnableInterrupts(LPTMR0, kLPTMR_TimerInterruptEnable);
mbed_official 121:7f86b4238bec 97 LPTMR_StartTimer(LPTMR0);
mbed_official 121:7f86b4238bec 98 }