mbed-os/targets/TARGET_ARM_FM/TARGET_FVP_MPS2/us_ticker.c

117 lines
4.2 KiB
C

/* mbed Microcontroller Library
* Copyright (c) 2006-2018 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_TIMER1 CMSDK_DUALTIMER1
#define US_TICKER_TIMER2 CMSDK_DUALTIMER2
#define US_TICKER_TIMER_IRQn DUALTIMER_IRQn
/** mbed OS HAL API defined us_ticker as an increment ticker
* MPS2 platform provided in SSE-200 are decrement tickers
* with interrupt fired counter reaches 0.
*
* So 2 Timers are used to construct mbed OS HAL ticker.
*
* TIMER1 is for counting, and returns inverted binary when read from it
* TIMER1 will be kept in free-running mode (default, and not generate interrupts)
*
* TIMER2 is for generating interrupts
* So TIMER2 is set to periodic mode, which start decrement counting form LOADVALUE generates interrupts at 0
* and TIMER2 also set into one-shot mode, which counter halts when is reaches 0
*/
static int us_ticker_inited = 0;
void us_ticker_init(void)
{
if (us_ticker_inited) {
us_ticker_disable_interrupt();
return;
}
US_TICKER_TIMER1->TimerControl = 0x0ul; // disable TIMER1 and reset all control
US_TICKER_TIMER2->TimerControl = 0x0ul; // disable TIMER2 and reset all control
US_TICKER_TIMER1->TimerLoad = 0xFFFFFFFFul;
US_TICKER_TIMER2->TimerLoad = 0xFFFFFFFFul;
US_TICKER_TIMER1->TimerControl |= CMSDK_DUALTIMER1_CTRL_SIZE_Msk; // set TIMER1 to 32 bit counter
US_TICKER_TIMER2->TimerControl |= CMSDK_DUALTIMER2_CTRL_SIZE_Msk; // set TIMER2 to 32 bit counter
US_TICKER_TIMER1->TimerControl |= 0x1 << CMSDK_DUALTIMER1_CTRL_PRESCALE_Pos; // set TIMER1 with 4 stages prescale
US_TICKER_TIMER2->TimerControl |= 0x1 << CMSDK_DUALTIMER2_CTRL_PRESCALE_Pos; // set TIMER2 with 4 stages prescale
US_TICKER_TIMER2->TimerControl |= CMSDK_DUALTIMER2_CTRL_MODE_Msk; // set TIMER2 periodic mode
US_TICKER_TIMER2->TimerControl |= CMSDK_DUALTIMER2_CTRL_ONESHOOT_Msk; // set TIMER2 one-shot mode
US_TICKER_TIMER1->TimerControl |= CMSDK_DUALTIMER1_CTRL_EN_Msk; // enable TIMER1 counter
NVIC_SetVector(US_TICKER_TIMER_IRQn, (uint32_t)us_ticker_irq_handler);
us_ticker_inited = 1;
}
void us_ticker_free(void)
{
US_TICKER_TIMER1->TimerControl &= ~CMSDK_DUALTIMER1_CTRL_EN_Msk; // disable TIMER1
US_TICKER_TIMER2->TimerControl &= ~CMSDK_DUALTIMER2_CTRL_EN_Msk; // disable TIMER2
us_ticker_disable_interrupt();
us_ticker_inited = 0;
}
uint32_t us_ticker_read()
{
return ~US_TICKER_TIMER1->TimerValue;
}
void us_ticker_set_interrupt(timestamp_t timestamp)
{
uint32_t delta = timestamp - us_ticker_read();
US_TICKER_TIMER2->TimerControl &= ~CMSDK_DUALTIMER2_CTRL_EN_Msk; // disable TIMER2
US_TICKER_TIMER2->TimerLoad = delta; // Set TIMER2 load value
US_TICKER_TIMER2->TimerControl |= CMSDK_DUALTIMER2_CTRL_INTEN_Msk; // enable TIMER2 interrupt
US_TICKER_TIMER2->TimerControl |= CMSDK_DUALTIMER2_CTRL_EN_Msk; // enable TIMER2 counter
NVIC_EnableIRQ(US_TICKER_TIMER_IRQn);
}
void us_ticker_fire_interrupt(void)
{
NVIC_EnableIRQ(US_TICKER_TIMER_IRQn);
NVIC_SetPendingIRQ(US_TICKER_TIMER_IRQn);
}
void us_ticker_disable_interrupt(void)
{
US_TICKER_TIMER2->TimerControl &= ~CMSDK_DUALTIMER2_CTRL_INTEN_Msk;
US_TICKER_TIMER2->TimerControl &= ~CMSDK_DUALTIMER2_CTRL_EN_Msk; // disable TIMER2
NVIC_DisableIRQ(US_TICKER_TIMER_IRQn);
}
void us_ticker_clear_interrupt(void)
{
US_TICKER_TIMER2->TimerIntClr = CMSDK_DUALTIMER2_INTCLR_Msk;
}
const ticker_info_t *us_ticker_get_info(void)
{
static const ticker_info_t info = {
1562500, // 4 stages prescaled from 25MHz (dived by 16)
32 // 32 bit counter
};
return &info;
}