circuitpython/ports/mimxrt10xx/tick.c

93 lines
3.5 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2017 Scott Shawcroft for Adafruit Industries
* Copyright (c) 2019 Artur Pacholec
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "tick.h"
#include "fsl_common.h"
#include "supervisor/shared/tick.h"
#include "shared-bindings/microcontroller/__init__.h"
#include "shared-bindings/microcontroller/Processor.h"
void SysTick_Handler(void) {
// SysTick interrupt handler called when the SysTick timer reaches zero
// (every millisecond).
common_hal_mcu_disable_interrupts();
// Read the control register to reset the COUNTFLAG.
(void) SysTick->CTRL;
common_hal_mcu_enable_interrupts();
// Do things common to all ports when the tick occurs
supervisor_tick();
}
void tick_init() {
uint32_t ticks_per_ms = common_hal_mcu_processor_get_frequency() / 1000;
SysTick_Config(ticks_per_ms-1);
}
void tick_delay(uint32_t us) {
uint32_t ticks_per_us = common_hal_mcu_processor_get_frequency() / 1000 / 1000;
uint32_t us_until_next_tick = SysTick->VAL / ticks_per_us;
uint32_t start_tick;
while (us >= us_until_next_tick) {
start_tick = SysTick->VAL; // wait for SysTick->VAL to RESET
while (SysTick->VAL < start_tick) {}
us -= us_until_next_tick;
us_until_next_tick = 1000;
}
while (SysTick->VAL > ((us_until_next_tick - us) * ticks_per_us)) {}
}
// us counts down!
void current_tick(uint64_t* ms, uint32_t* us_until_ms) {
uint32_t ticks_per_us = common_hal_mcu_processor_get_frequency() / 1000 / 1000;
// We disable interrupts to prevent ticks_ms from changing while we grab it.
common_hal_mcu_disable_interrupts();
uint32_t tick_status = SysTick->CTRL;
uint32_t current_us = SysTick->VAL;
uint32_t tick_status2 = SysTick->CTRL;
uint64_t current_ms = supervisor_ticks_ms64();
// The second clause ensures our value actually rolled over. Its possible it hit zero between
// the VAL read and CTRL read.
if ((tick_status & SysTick_CTRL_COUNTFLAG_Msk) != 0 ||
((tick_status2 & SysTick_CTRL_COUNTFLAG_Msk) != 0 && current_us > ticks_per_us)) {
current_ms++;
}
common_hal_mcu_enable_interrupts();
*ms = current_ms;
*us_until_ms = current_us / ticks_per_us;
}
void wait_until(uint64_t ms, uint32_t us_until_ms) {
uint32_t ticks_per_us = common_hal_mcu_processor_get_frequency() / 1000 / 1000;
while (supervisor_ticks_ms64() <= ms && SysTick->VAL / ticks_per_us >= us_until_ms) {}
}