From 32d7cf6e441660caed00620309d1faa4b7df5dd4 Mon Sep 17 00:00:00 2001
From: Damien George
Date: Thu, 21 Apr 2016 11:43:37 +0100
Subject: esp8266: Implement basic deep-sleep capabilities.

Use the machine.deepsleep() function to enter the sleep mode.  Use the
RTC to configure the alarm to wake the device.

Basic use is the following:

    import machine

    # configure RTC's ALARM0 to wake device from deep sleep
    rtc = machine.RTC()
    rtc.irq(trigger=rtc.ALARM0, wake=machine.DEEPSLEEP)

    # do other things
    # ...

    # set ALARM0's alarm to wake after 10 seconds
    rtc.alarm(rtc.ALARM0, 10000)

    # enter deep-sleep state (system is reset upon waking)
    machine.deepsleep()

To detect if the system woke from a deep sleep use:

    if machine.reset_cause() == machine.DEEPSLEEP_RESET:
        print('woke from deep sleep')
---
 esp8266/modmachine.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

(limited to 'esp8266/modmachine.c')

diff --git a/esp8266/modmachine.c b/esp8266/modmachine.c
index 83fb8d350..c75f6e528 100644
--- a/esp8266/modmachine.c
+++ b/esp8266/modmachine.c
@@ -33,14 +33,20 @@
 #include "extmod/machine_i2c.h"
 #include "utils.h"
 #include "modpyb.h"
+#include "modpybrtc.h"
 
 #include "os_type.h"
 #include "osapi.h"
 #include "etshal.h"
+#include "ets_alt_task.h"
 #include "user_interface.h"
 
 #if MICROPY_PY_MACHINE
 
+//#define MACHINE_WAKE_IDLE (0x01)
+//#define MACHINE_WAKE_SLEEP (0x02)
+#define MACHINE_WAKE_DEEPSLEEP (0x04)
+
 STATIC mp_obj_t machine_freq(mp_uint_t n_args, const mp_obj_t *args) {
     if (n_args == 0) {
         // get
@@ -75,6 +81,40 @@ STATIC mp_obj_t machine_unique_id(void) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_0(machine_unique_id_obj, machine_unique_id);
 
+STATIC mp_obj_t machine_deepsleep(void) {
+    // default to sleep forever
+    uint32_t sleep_us = 0;
+
+    // see if RTC.ALARM0 should wake the device
+    if (pyb_rtc_alarm0_wake & MACHINE_WAKE_DEEPSLEEP) {
+        uint64_t t = pyb_rtc_get_us_since_2000();
+        if (pyb_rtc_alarm0_expiry <= t) {
+            sleep_us = 1; // alarm already expired so wake immediately
+        } else {
+            uint64_t delta = pyb_rtc_alarm0_expiry - t;
+            if (delta <= 0xffffffff) {
+                // sleep for the desired time
+                sleep_us = delta;
+            } else {
+                // overflow, just set to maximum sleep time
+                sleep_us = 0xffffffff;
+            }
+        }
+    }
+
+    // put the device in a deep-sleep state
+    system_deep_sleep_set_option(0); // default power down mode; TODO check this
+    system_deep_sleep(sleep_us);
+
+    for (;;) {
+        // we must not return
+        ets_loop_iter();
+    }
+
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_0(machine_deepsleep_obj, machine_deepsleep);
+
 typedef struct _esp_timer_obj_t {
     mp_obj_base_t base;
     os_timer_t timer;
@@ -160,7 +200,9 @@ STATIC const mp_rom_map_elem_t machine_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_reset), MP_ROM_PTR(&machine_reset_obj) },
     { MP_ROM_QSTR(MP_QSTR_reset_cause), MP_ROM_PTR(&machine_reset_cause_obj) },
     { MP_ROM_QSTR(MP_QSTR_unique_id), MP_ROM_PTR(&machine_unique_id_obj) },
+    { MP_ROM_QSTR(MP_QSTR_deepsleep), MP_ROM_PTR(&machine_deepsleep_obj) },
 
+    { MP_ROM_QSTR(MP_QSTR_RTC), MP_ROM_PTR(&pyb_rtc_type) },
     { MP_ROM_QSTR(MP_QSTR_Timer), MP_ROM_PTR(&esp_timer_type) },
     { MP_ROM_QSTR(MP_QSTR_Pin), MP_ROM_PTR(&pyb_pin_type) },
     { MP_ROM_QSTR(MP_QSTR_PWM), MP_ROM_PTR(&pyb_pwm_type) },
@@ -168,6 +210,14 @@ STATIC const mp_rom_map_elem_t machine_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&pyb_uart_type) },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&machine_i2c_type) },
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&pyb_spi_type) },
+
+    // wake abilities
+    { MP_ROM_QSTR(MP_QSTR_DEEPSLEEP), MP_ROM_INT(MACHINE_WAKE_DEEPSLEEP) },
+
+    // reset causes
+    { MP_ROM_QSTR(MP_QSTR_PWR_ON_RESET), MP_ROM_INT(REASON_EXT_SYS_RST) },
+    { MP_ROM_QSTR(MP_QSTR_HARD_RESET), MP_ROM_INT(REASON_EXT_SYS_RST) },
+    { MP_ROM_QSTR(MP_QSTR_DEEPSLEEP_RESET), MP_ROM_INT(REASON_DEEP_SLEEP_AWAKE) },
 };
 
 STATIC MP_DEFINE_CONST_DICT(machine_module_globals, machine_module_globals_table);
-- 
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