added prescaler for 16 bit pwm in LPC1347 target
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Diff: targets/cmsis/TARGET_ARM_SSG/TARGET_BEETLE/systick_timer.c
- Revision:
- 144:ef7eb2e8f9f7
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/targets/cmsis/TARGET_ARM_SSG/TARGET_BEETLE/systick_timer.c Fri Sep 02 15:07:44 2016 +0100 @@ -0,0 +1,94 @@ +/* + * PackageLicenseDeclared: Apache-2.0 + * Copyright (c) 2015 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 "cmsis.h" +#include "systick_timer.h" + +volatile uint32_t MyTicks; + +/* Private Data SysTick */ +static uint32_t clock; + +/* + * This Timer is written for MBED OS so the interrupt + * is used to keep track of the overflow. + */ +#define SYSTICK_MAX_RELOAD 0xFFFFFFFF +#define SYSTICK_DIVIDER_US (SystemCoreClock/1000000) + +void SysTick_IRQ_Handler(void) +{ + MyTicks++; +#if 0 + printf("System Tick Interrupt: %u\n\r", MyTicks); +#endif +} + +/* + * SysTick_Initialize(): Initializes the SysTick timer + */ +void SysTick_Initialize(void) +{ + clock = SYSTICK_MAX_RELOAD; +#if 0 + printf("\n\rEnable System Tick Interrupt...\n\r"); +#endif + MyTicks=0; + + /* SysTick Reload Value Register */ + SysTick->LOAD = clock; + + /* + * SysTick_CTRL_CLKSOURCE_Msk : Use core's clock + * SysTick_CTRL_ENABLE_Msk : Enable SysTick + * SysTick_CTRL_TICKINT_Msk : Active the SysTick interrupt on the NVIC + */ + SysTick->CTRL = SysTick_CTRL_CLKSOURCE_Msk + | SysTick_CTRL_ENABLE_Msk + | SysTick_CTRL_TICKINT_Msk; + + /* Register the Interrupt */ + NVIC_SetVector(SysTick_IRQn, (uint32_t)SysTick_IRQ_Handler); + NVIC_EnableIRQ(SysTick_IRQn); +} + +/* + * SysTick_Disable(): Disables the SysTick timer + */ +void SysTick_Disable(void) +{ + /* Disable SysTick */ + SysTick->CTRL = 0; +} + +/* + * SysTick_Read(): Read SysTick Value + * @return: the SysTick VALUE + */ +uint32_t SysTick_Read(void) +{ + return ((clock - (SysTick->VAL)) / SYSTICK_DIVIDER_US); +} + +/* + * SysTick_Overflow(): Read SysTick Overflow Value + * @return: the SysTick Overflow VALUE + */ +uint32_t SysTick_Overflow(void) +{ + return MyTicks; +}