mbed-os/targets/TARGET_NUVOTON/nu_timer.c

68 lines
2.0 KiB
C

/* mbed Microcontroller Library
* Copyright (c) 2015-2016 Nuvoton
*
* 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 "nu_timer.h"
#include "mbed_power_mgmt.h"
#include "mbed_critical.h"
#include "us_ticker_api.h"
#include "mbed_assert.h"
void nu_countdown_init(struct nu_countdown_ctx_s *ctx, us_timestamp_t interval_us)
{
core_util_critical_section_enter();
sleep_manager_lock_deep_sleep();
ctx->_ticker_data = get_us_ticker_data();
ctx->_interval_end_us = ticker_read_us(ctx->_ticker_data) + interval_us;
ctx->_expired = false;
core_util_critical_section_exit();
}
bool nu_countdown_expired(struct nu_countdown_ctx_s *ctx)
{
core_util_critical_section_enter();
if (! ctx->_expired) {
ctx->_expired = ticker_read_us(ctx->_ticker_data) >= ctx->_interval_end_us;
}
core_util_critical_section_exit();
return ctx->_expired;
}
void nu_countdown_free(struct nu_countdown_ctx_s *ctx)
{
core_util_critical_section_enter();
sleep_manager_unlock_deep_sleep();
core_util_critical_section_exit();
}
void nu_busy_wait_us(uint32_t us)
{
const uint32_t bits = us_ticker_get_info()->bits;
const uint32_t mask = (1 << bits) - 1;
MBED_ASSERT(us_ticker_get_info()->frequency == 1000000);
uint32_t prev = us_ticker_read();
while (1) {
const uint32_t cur = us_ticker_read();
const uint32_t elapsed = (cur - prev) & mask;
if (elapsed > us) {
break;
}
us -= elapsed;
prev = cur;
}
}