mirror of https://github.com/ARMmbed/mbed-os.git
110 lines
2.9 KiB
C
110 lines
2.9 KiB
C
/* mbed Microcontroller Library
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* (C)Copyright TOSHIBA ELECTRONIC DEVICES & STORAGE CORPORATION 2017 All rights reserved
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "us_ticker_api.h"
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#include "mbed_critical.h"
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#define TMR16A_100US 0x960 // fsys = fc = 24MHz, Ttmra = 1/24us, 100us*24us = 2400 = 0x960
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#define TMR16A_SYSCK ((uint32_t)0x00000001)
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#define TMR16A_RUN ((uint32_t)0x00000001)
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#define TMR16A_STOP ((uint32_t)0x00000000)
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#define OVERFLOW_32BIT (0xFFFFFFFF / 0x64)
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static uint8_t us_ticker_inited = 0; // Is ticker initialized yet?
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static volatile uint32_t ticker_int_counter = 0; // Amount of overflows until user interrupt
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static volatile uint32_t us_ticker = 0; // timer counter
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void INT16A0_IRQHandler(void)
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{
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us_ticker++;
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if (us_ticker > OVERFLOW_32BIT) {
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us_ticker = 0;
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}
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}
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void INT16A1_IRQHandler(void)
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{
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us_ticker_irq_handler();
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}
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// initialize us_ticker
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void us_ticker_init(void)
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{
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// Enable clock supply to TA0
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CG_SetFcPeriphA(CG_FC_PERIPH_TMR16A, ENABLE);
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if (us_ticker_inited) {
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return;
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}
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us_ticker_inited = 1;
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// Stops and clear count operation
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TSB_T16A0->RUN = TMR16A_STOP;
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TSB_T16A0->CR = TMR16A_SYSCK;
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// Permits INTTA0 interrupt
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NVIC_EnableIRQ(INT16A0_IRQn);
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// Match counter set to max value
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TSB_T16A0->RG = TMR16A_100US;
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TSB_T16A0->RUN = TMR16A_RUN;
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}
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uint32_t us_ticker_read(void)
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{
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uint32_t ret_val = 0;
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if (!us_ticker_inited) {
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us_ticker_init();
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}
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uint32_t tickerbefore = 0;
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do {
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tickerbefore = us_ticker;
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ret_val = (us_ticker * 100);
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} while (tickerbefore != us_ticker);
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return ret_val;
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}
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void us_ticker_set_interrupt(timestamp_t timestamp)
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{
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uint32_t delta = 0;
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// Stops and clear count operation
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TSB_T16A1->RUN = TMR16A_STOP;
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TSB_T16A1->CR = TMR16A_SYSCK;
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// Set the compare register
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delta = (timestamp - us_ticker_read());
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TSB_T16A1->RG = delta;
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// Set Interrupt
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NVIC_EnableIRQ(INT16A1_IRQn);
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// Start TMR_TA1 timer
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TSB_T16A1->RUN = TMR16A_RUN;
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}
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void us_ticker_fire_interrupt(void)
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{
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NVIC_SetPendingIRQ(INT16A1_IRQn);
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}
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void us_ticker_disable_interrupt(void)
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{
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NVIC_DisableIRQ(INT16A1_IRQn);
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}
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void us_ticker_clear_interrupt(void)
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{
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//no flags to clear
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}
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