mirror of https://github.com/ARMmbed/mbed-os.git
81 lines
2.9 KiB
C
81 lines
2.9 KiB
C
/* mbed Microcontroller Library
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* Copyright (c) 2006-2013 ARM Limited
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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 "sleep_api.h"
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#include "cmsis.h"
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#include "mbed_interface.h"
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#include "softdevice_handler.h"
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#include "nrf_soc.h"
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// Mask of reserved bits of the register ICSR in the System Control Block peripheral
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// In this case, bits which are equal to 0 are the bits reserved in this register
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#define SCB_ICSR_RESERVED_BITS_MASK 0x9E43F03F
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#define FPU_EXCEPTION_MASK 0x0000009F
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void hal_sleep(void)
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{
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// ensure debug is disconnected if semihost is enabled....
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// Trigger an event when an interrupt is pending. This allows to wake up
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// the processor from disabled interrupts.
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SCB->SCR |= SCB_SCR_SEVONPEND_Msk;
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#if defined(NRF52) || defined(NRF52840_XXAA)
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/* Clear exceptions and PendingIRQ from the FPU unit */
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__set_FPSCR(__get_FPSCR() & ~(FPU_EXCEPTION_MASK));
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(void) __get_FPSCR();
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NVIC_ClearPendingIRQ(FPU_IRQn);
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#endif
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// If the SoftDevice is enabled, its API must be used to go to sleep.
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if (softdevice_handler_is_enabled()) {
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sd_power_mode_set(NRF_POWER_MODE_LOWPWR);
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sd_app_evt_wait();
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} else {
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NRF_POWER->TASKS_LOWPWR = 1;
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// Note: it is not sufficient to just use WFE here, since the internal
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// event register may be already set from an event that occurred in the
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// past (like an SVC call to the SoftDevice) and in such case WFE will
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// just clear the register and continue execution.
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// Therefore, the strategy here is to first clear the event register
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// by using SEV/WFE pair, and then execute WFE again, unless there is
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// a pending interrupt.
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// Set an event and wake up whatsoever, this will clear the event
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// register from all previous events set (SVC call included)
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__SEV();
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__WFE();
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// Test if there is an interrupt pending (mask reserved regions)
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if (SCB->ICSR & (SCB_ICSR_RESERVED_BITS_MASK)) {
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// Ok, there is an interrut pending, no need to go to sleep
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return;
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} else {
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// next event will wakeup the CPU
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// If an interrupt occured between the test of SCB->ICSR and this
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// instruction, WFE will just not put the CPU to sleep
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__WFE();
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}
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}
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}
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void hal_deepsleep(void)
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{
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hal_sleep();
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// NRF_POWER->SYSTEMOFF=1;
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}
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