added prescaler for 16 bit pwm in LPC1347 target
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Diff: targets/hal/TARGET_Freescale/TARGET_KSDK2_MCUS/TARGET_MCU_K64F/us_ticker.c
- Revision:
- 144:ef7eb2e8f9f7
diff -r 423e1876dc07 -r ef7eb2e8f9f7 targets/hal/TARGET_Freescale/TARGET_KSDK2_MCUS/TARGET_MCU_K64F/us_ticker.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/targets/hal/TARGET_Freescale/TARGET_KSDK2_MCUS/TARGET_MCU_K64F/us_ticker.c Fri Sep 02 15:07:44 2016 +0100 @@ -0,0 +1,90 @@ +/* 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.h" +#include "fsl_clock_config.h" + +static int us_ticker_inited = 0; + +void us_ticker_init(void) { + if (us_ticker_inited) { + return; + } + us_ticker_inited = 1; + // Need to initialize the clocks here as ticker init gets called before mbed_sdk_init + if (SystemCoreClock == DEFAULT_SYSTEM_CLOCK) + BOARD_BootClockRUN(); + //Common for ticker/timer + uint32_t busClock; + // Structure to initialize PIT + pit_config_t pitConfig; + + PIT_GetDefaultConfig(&pitConfig); + PIT_Init(PIT, &pitConfig); + + busClock = CLOCK_GetFreq(kCLOCK_BusClk); + + //Timer + PIT_SetTimerPeriod(PIT, kPIT_Chnl_0, busClock / 1000000 - 1); + PIT_SetTimerPeriod(PIT, kPIT_Chnl_1, 0xFFFFFFFF); + PIT_SetTimerChainMode(PIT, kPIT_Chnl_1, true); + PIT_StartTimer(PIT, kPIT_Chnl_0); + PIT_StartTimer(PIT, kPIT_Chnl_1); + + //Ticker + PIT_SetTimerPeriod(PIT, kPIT_Chnl_2, busClock / 1000000 - 1); + PIT_SetTimerChainMode(PIT, kPIT_Chnl_3, true); + NVIC_SetVector(PIT3_IRQn, (uint32_t)us_ticker_irq_handler); + NVIC_EnableIRQ(PIT3_IRQn); +} + + +uint32_t us_ticker_read() { + if (!us_ticker_inited) { + us_ticker_init(); + } + + return ~(PIT_GetCurrentTimerCount(PIT, kPIT_Chnl_1)); +} + +void us_ticker_disable_interrupt(void) { + PIT_DisableInterrupts(PIT, kPIT_Chnl_3, kPIT_TimerInterruptEnable); +} + +void us_ticker_clear_interrupt(void) { + PIT_ClearStatusFlags(PIT, kPIT_Chnl_3, PIT_TFLG_TIF_MASK); +} + +void us_ticker_set_interrupt(timestamp_t timestamp) { + int delta = (int)(timestamp - us_ticker_read()); + if (delta <= 0) { + // This event was in the past. + // Set the interrupt as pending, but don't process it here. + // This prevents a recurive loop under heavy load + // which can lead to a stack overflow. + NVIC_SetPendingIRQ(PIT3_IRQn); + return; + } + + PIT_StopTimer(PIT, kPIT_Chnl_3); + PIT_StopTimer(PIT, kPIT_Chnl_2); + PIT_SetTimerPeriod(PIT, kPIT_Chnl_3, (uint32_t)delta); + PIT_EnableInterrupts(PIT, kPIT_Chnl_3, kPIT_TimerInterruptEnable); + PIT_StartTimer(PIT, kPIT_Chnl_3); + PIT_StartTimer(PIT, kPIT_Chnl_2); +}