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/* 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"
#define US_TICKER_TIMER_IRQn RIT_IRQn
int us_ticker_inited = 0;
void us_ticker_init(void) {
if (us_ticker_inited) return;
us_ticker_inited = 1;
// Enable the RIT clock
LPC_SYSCON->SYSAHBCLKCTRL1 |= (1 << 1);
// Clear peripheral reset the RIT
LPC_SYSCON->PRESETCTRL1 |= (1 << 1);
LPC_SYSCON->PRESETCTRL1 &= ~(1 << 1);
LPC_RIT->MASK = 0;
LPC_RIT->MASK_H = 0;
LPC_RIT->COUNTER = 0;
LPC_RIT->COUNTER_H = 0;
LPC_RIT->COMPVAL = 0xffffffff;
LPC_RIT->COMPVAL_H = 0x0000ffff;
// Timer enable, enable for debug
LPC_RIT->CTRL = 0xC;
NVIC_SetVector(US_TICKER_TIMER_IRQn, (uint32_t)us_ticker_irq_handler);
NVIC_EnableIRQ(US_TICKER_TIMER_IRQn);
}
uint32_t us_ticker_read() {
if (!us_ticker_inited)
us_ticker_init();
uint64_t temp;
temp = LPC_RIT->COUNTER | ((uint64_t)LPC_RIT->COUNTER_H << 32);
temp /= (SystemCoreClock/1000000);
return (uint32_t)temp;
}
void us_ticker_set_interrupt(timestamp_t timestamp) {
uint64_t temp = ((uint64_t)timestamp * (SystemCoreClock/1000000));
LPC_RIT->COMPVAL = (temp & 0xFFFFFFFFL);
LPC_RIT->COMPVAL_H = ((temp >> 32)& 0x0000FFFFL);
}
void us_ticker_disable_interrupt(void) {
LPC_RIT->CTRL |= (1 << 3);
}
void us_ticker_clear_interrupt(void) {
LPC_RIT->CTRL |= (1 << 0);
}
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