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/*
* MIT License
*
* Copyright (c) 2020 Joey Castillo
*
* 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.
*/
////< @file watch_deepsleep.h
/** @addtogroup deepsleep Deep Sleep Control
* @brief This section covers functions related to preparing for and entering BACKUP mode, the
* deepest sleep mode available on the SAM L22
*/
/// @{
/** @brief Registers a callback on one of the RTC's external wake pins, which can wake the device
* from deep sleep (aka BACKUP) mode.
* @param pin Either pin BTN_ALARM, A2, or A4. These are the three external wake pins. If the pin
* is BTN_ALARM, this function also enables an internal pull down on that pin.
* @param callback The callback to be called if this pin triggers outside of deep sleep mode. If
* this is NULL, no callback will be called even in normal mode, but the interrupt
* will still be enabled so that it can wake from deep sleep or backup mode.
* @param level The level you wish to scan for: true for rising, false for falling. Note that you
* cannot scan for both rising and falling edges like you can with the external interrupt
* pins; with the external wake interrupt, you can only get one or the other.
* @note When in normal or STANDBY mode, this will function much like a standard external interrupt
* situation: these pins will wake from standby, and your callback will be called. However,
* if the device enters deep sleep and one of these pins wakes the device, your callback
* WILL NOT be called, as the device is basically waking from reset at that point.
* @warning As of the current SAM L22 silicon revision (rev B), the BTN_ALARM pin cannot wake the
* device from BACKUP mode. You can still use this function to register a BTN_ALARM interrupt
* in normal or deep sleep mode, but to wake from BACKUP, you will need to use pin A2 or A4.
*/
void watch_register_extwake_callback(uint8_t pin, ext_irq_cb_t callback, bool level);
/** @brief Unregisters the interrupt on one of the EXTWAKE pins. This will prevent a value change on
* one of these pins from waking the device from deep sleep or BACKUP modes.
* @param pin Either pin BTN_ALARM, A2, or A4. If the pin is BTN_ALARM, this function DOES NOT disable
* the internal pull down on that pin.
*/
void watch_disable_extwake_interrupt(uint8_t pin, ext_irq_cb_t callback, bool level);
/** @brief Stores data in one of the RTC's backup registers, which retain their data in the deep sleep
and backup modes.
* @param data An unsigned 32 bit integer with the data you wish to store.
* @param reg A register from 0-7.
*/
void watch_store_backup_data(uint32_t data, uint8_t reg);
/** @brief Gets 32 bits of data from the RTC's backup register.
* @param reg A register from 0-7.
* @return An unsigned 32 bit integer with the from the backup register.
*/
uint32_t watch_get_backup_data(uint8_t reg);
/** @brief Enters a deep sleep mode by disabling RAM retention and all peripherals except the RTC and
* (optionally) the LCD. You can wake from this mode by pressing the ALARM button.
* @param message Either NULL, or a string representing a message to display while in deep sleep mode. The
* message will be displayed at position 0, so you should pad out the beginning of the string
* with spaces if you wish for the message to appear on line 2, i.e. " SLEEP". If this
* parameter is NULL, the screen will be blanked, and this function will disable the SLCD
* peripheral for additional power savings. (also note that while the message will replace any
* text on the display, this function will not clear any indicators you have set. This is by
* design, in case you wish to leave an indicator lit in sleep mode.)
* @details This deep sleep mode is not the lowest power mode available (see watch_enter_backup_mode), but
* it has the benefit of being able to wake with a press of the ALARM button, and provides an option
* for displaying a message to the user when asleep. The only way to wake from this mode is by
* pressing the ALARM button, or receiving an interrupt on pin A2 or A4 of the nine-pin connector.
* (An alarm interrupt would also work, but this has not yet been implemented.) This function enables
* the ALARM button interrupt for you, but if you wish to wake from the A2 or A4 RTC interrupt, you
* must configure them by calling watch_register_extwake_callback. Note however that your callback
* will not be called in this case.
* Power consumption in deep sleep mode varies a bit with the battery voltage and the temperature,
* but at 3 V and ~25° C you can eoughly estimate:
* * ~12µA current draw with the LCD controller on (message != NULL)
* * ~6.5µA current draw with the LCD controller off (message == NULL)
* @note With RAM powered off, your application state will be cleared as soon as you call this function, and
* when the user wakes up the watch, your app will effectively be waking from reset. Your app's @ref
* app_wake_from_deep_sleep function will be called to give your app a chance to restore any state that
* you stored using @ref watch_store_backup_data.
*/
void watch_enter_deep_sleep(char *message);
/** @brief Enters the SAM L22's lowest-power mode, BACKUP.
* @details This function does some housekeeping before entering BACKUP mode. It first disables all
* peripherals except for the RTC, and disables the tick interrupt (since that would wake
* us up from deep sleep). It also sets an external wake source on the ALARM button, if one
* was not already set. If you wish to wake from another source, such as one of the external
* wake interrupt pins on the 9-pin connector, set that up prior to calling this function.
* @note If you have a callback set for an external wake interrupt, it will be called if triggered while
* in ACTIVE, IDLE or STANDBY modes, but it *will not be called* when waking from BACKUP.
* Waking from backup is effectively like waking from reset, except that your @ref
* app_wake_from_deep_sleep function will be called.
* @warning On current revisions of the SAM L22 silicon, the ALARM_BTN pin (PA02 RTC/IN2) cannot wake
* the device from deep sleep mode. There is an errata note (Reference: 15010) that says that
* due to a silicon bug, RTC/IN2 is not functional in BACKUP. As a result, you should not call
* this function unless you have a device on the nine-pin connector with an external interrupt
* on pin A2 or A4 (i.e. an accelerometer with an interrupt pin).
*/
void watch_enter_backup_mode();
/// @}
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