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_KL43Z/us_ticker.c@144:ef7eb2e8f9f7, 2016-09-02 (annotated)

Committer:
<>
Date:
Fri Sep 02 15:07:44 2016 +0100
Revision:
144:ef7eb2e8f9f7
This updates the lib to the mbed lib v125

Who changed what in which revision?

UserRevisionLine numberNew contents of line
<> 144:ef7eb2e8f9f7 1 /* mbed Microcontroller Library
<> 144:ef7eb2e8f9f7 2 * Copyright (c) 2006-2013 ARM Limited
<> 144:ef7eb2e8f9f7 3 *
<> 144:ef7eb2e8f9f7 4 * Licensed under the Apache License, Version 2.0 (the "License");
<> 144:ef7eb2e8f9f7 5 * you may not use this file except in compliance with the License.
<> 144:ef7eb2e8f9f7 6 * You may obtain a copy of the License at
<> 144:ef7eb2e8f9f7 7 *
<> 144:ef7eb2e8f9f7 8 * http://www.apache.org/licenses/LICENSE-2.0
<> 144:ef7eb2e8f9f7 9 *
<> 144:ef7eb2e8f9f7 10 * Unless required by applicable law or agreed to in writing, software
<> 144:ef7eb2e8f9f7 11 * distributed under the License is distributed on an "AS IS" BASIS,
<> 144:ef7eb2e8f9f7 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
<> 144:ef7eb2e8f9f7 13 * See the License for the specific language governing permissions and
<> 144:ef7eb2e8f9f7 14 * limitations under the License.
<> 144:ef7eb2e8f9f7 15 */
<> 144:ef7eb2e8f9f7 16 #include <stddef.h>
<> 144:ef7eb2e8f9f7 17 #include "us_ticker_api.h"
<> 144:ef7eb2e8f9f7 18 #include "PeripheralNames.h"
<> 144:ef7eb2e8f9f7 19 #include "fsl_pit.h"
<> 144:ef7eb2e8f9f7 20 #include "fsl_lptmr.h"
<> 144:ef7eb2e8f9f7 21 #include "fsl_clock_config.h"
<> 144:ef7eb2e8f9f7 22
<> 144:ef7eb2e8f9f7 23 static int us_ticker_inited = 0;
<> 144:ef7eb2e8f9f7 24
<> 144:ef7eb2e8f9f7 25 void us_ticker_init(void) {
<> 144:ef7eb2e8f9f7 26 if (us_ticker_inited) {
<> 144:ef7eb2e8f9f7 27 return;
<> 144:ef7eb2e8f9f7 28 }
<> 144:ef7eb2e8f9f7 29 us_ticker_inited = 1;
<> 144:ef7eb2e8f9f7 30
<> 144:ef7eb2e8f9f7 31 // Need to initialize the clocks here as ticker init gets called before mbed_sdk_init
<> 144:ef7eb2e8f9f7 32 if (SystemCoreClock == DEFAULT_SYSTEM_CLOCK)
<> 144:ef7eb2e8f9f7 33 BOARD_BootClockRUN();
<> 144:ef7eb2e8f9f7 34
<> 144:ef7eb2e8f9f7 35 //Timer uses PIT
<> 144:ef7eb2e8f9f7 36 //Common for ticker/timer
<> 144:ef7eb2e8f9f7 37 uint32_t busClock;
<> 144:ef7eb2e8f9f7 38
<> 144:ef7eb2e8f9f7 39 // Structure to initialize PIT
<> 144:ef7eb2e8f9f7 40 pit_config_t pitConfig;
<> 144:ef7eb2e8f9f7 41
<> 144:ef7eb2e8f9f7 42 PIT_GetDefaultConfig(&pitConfig);
<> 144:ef7eb2e8f9f7 43 PIT_Init(PIT, &pitConfig);
<> 144:ef7eb2e8f9f7 44
<> 144:ef7eb2e8f9f7 45 busClock = CLOCK_GetFreq(kCLOCK_BusClk);
<> 144:ef7eb2e8f9f7 46
<> 144:ef7eb2e8f9f7 47 PIT_SetTimerPeriod(PIT, kPIT_Chnl_0, busClock / 1000000 - 1);
<> 144:ef7eb2e8f9f7 48 PIT_SetTimerPeriod(PIT, kPIT_Chnl_1, 0xFFFFFFFF);
<> 144:ef7eb2e8f9f7 49 PIT_SetTimerChainMode(PIT, kPIT_Chnl_1, true);
<> 144:ef7eb2e8f9f7 50 PIT_StartTimer(PIT, kPIT_Chnl_0);
<> 144:ef7eb2e8f9f7 51 PIT_StartTimer(PIT, kPIT_Chnl_1);
<> 144:ef7eb2e8f9f7 52
<> 144:ef7eb2e8f9f7 53 //Ticker uses LPTMR
<> 144:ef7eb2e8f9f7 54 lptmr_config_t lptmrConfig;
<> 144:ef7eb2e8f9f7 55 LPTMR_GetDefaultConfig(&lptmrConfig);
<> 144:ef7eb2e8f9f7 56 lptmrConfig.prescalerClockSource = kLPTMR_PrescalerClock_0;
<> 144:ef7eb2e8f9f7 57 LPTMR_Init(LPTMR0, &lptmrConfig);
<> 144:ef7eb2e8f9f7 58
<> 144:ef7eb2e8f9f7 59 busClock = CLOCK_GetFreq(kCLOCK_McgInternalRefClk);
<> 144:ef7eb2e8f9f7 60 LPTMR_SetTimerPeriod(LPTMR0, busClock / 1000000 - 1);
<> 144:ef7eb2e8f9f7 61 /* Set interrupt handler */
<> 144:ef7eb2e8f9f7 62 NVIC_SetVector(LPTMR0_IRQn, (uint32_t)us_ticker_irq_handler);
<> 144:ef7eb2e8f9f7 63 NVIC_EnableIRQ(LPTMR0_IRQn);
<> 144:ef7eb2e8f9f7 64 }
<> 144:ef7eb2e8f9f7 65
<> 144:ef7eb2e8f9f7 66
<> 144:ef7eb2e8f9f7 67 uint32_t us_ticker_read() {
<> 144:ef7eb2e8f9f7 68 if (!us_ticker_inited) {
<> 144:ef7eb2e8f9f7 69 us_ticker_init();
<> 144:ef7eb2e8f9f7 70 }
<> 144:ef7eb2e8f9f7 71
<> 144:ef7eb2e8f9f7 72 return ~(PIT_GetCurrentTimerCount(PIT, kPIT_Chnl_1));
<> 144:ef7eb2e8f9f7 73 }
<> 144:ef7eb2e8f9f7 74
<> 144:ef7eb2e8f9f7 75 void us_ticker_disable_interrupt(void) {
<> 144:ef7eb2e8f9f7 76 LPTMR_DisableInterrupts(LPTMR0, kLPTMR_TimerInterruptEnable);
<> 144:ef7eb2e8f9f7 77 }
<> 144:ef7eb2e8f9f7 78
<> 144:ef7eb2e8f9f7 79 void us_ticker_clear_interrupt(void) {
<> 144:ef7eb2e8f9f7 80 LPTMR_ClearStatusFlags(LPTMR0, kLPTMR_TimerCompareFlag);
<> 144:ef7eb2e8f9f7 81 }
<> 144:ef7eb2e8f9f7 82
<> 144:ef7eb2e8f9f7 83 void us_ticker_set_interrupt(timestamp_t timestamp) {
<> 144:ef7eb2e8f9f7 84 int delta = (int)(timestamp - us_ticker_read());
<> 144:ef7eb2e8f9f7 85 if (delta <= 0) {
<> 144:ef7eb2e8f9f7 86 // This event was in the past.
<> 144:ef7eb2e8f9f7 87 // Set the interrupt as pending, but don't process it here.
<> 144:ef7eb2e8f9f7 88 // This prevents a recurive loop under heavy load
<> 144:ef7eb2e8f9f7 89 // which can lead to a stack overflow.
<> 144:ef7eb2e8f9f7 90 NVIC_SetPendingIRQ(LPTMR0_IRQn);
<> 144:ef7eb2e8f9f7 91 return;
<> 144:ef7eb2e8f9f7 92 }
<> 144:ef7eb2e8f9f7 93
<> 144:ef7eb2e8f9f7 94 LPTMR_StopTimer(LPTMR0);
<> 144:ef7eb2e8f9f7 95 LPTMR_SetTimerPeriod(LPTMR0, (uint32_t)delta);
<> 144:ef7eb2e8f9f7 96 LPTMR_EnableInterrupts(LPTMR0, kLPTMR_TimerInterruptEnable);
<> 144:ef7eb2e8f9f7 97 LPTMR_StartTimer(LPTMR0);
<> 144:ef7eb2e8f9f7 98 }