add Low-Power demo

esp8266 · devyte · Feb 2, 2020 · Jan 6, 2020 · Jan 6, 2020 · Jan 9, 2020
commit 7d3ee8d7a0ad1e6c3da656964bb3bfaef4114ed8
diff --git a/libraries/esp8266/examples/LowPowerDemo/README.md b/libraries/esp8266/examples/LowPowerDemo/README.md
@@ -63,17 +63,17 @@ Like Automatic Modem Sleep, with similar restrictions.  Once configured it's imm
 
 ### Test 5 - Timed Light Sleep
 
-Similar to Deep Sleep, but it wakes with an interrupt at the next line in your code and continues.  The chip sleeps at 0.4 mA amperage until it is woken by the RTC timer.  If you have a design that needs to be woken frequently (more often than every 2 seconds) then you should consider using timed Light Sleep.  For sleep periods longer than 2 seconds, Deep Sleep will be more energy efficient.  The chip wakes after an interrupt in about 3 to 5.5 mS (regardless of CPU speed), but WiFi was turned off to enter timed Light Sleep so you will need to re-initialize it if you are using WiFi.  Any timers (including OS_timers and PWM) will keep the chip from going fully into timed Light Sleep, and it will fall through to the next line in your code if timers are enabled.
+Similar to Deep Sleep, but it wakes with an interrupt at the next line in your code and continues.  The chip sleeps at 0.4 mA amperage until it is woken by the RTC timer.  If you have a design that needs to be woken frequently (more often than every 2 seconds) then you should consider using timed Light Sleep.  For sleep periods longer than 2 seconds, Deep Sleep will be more energy efficient.  The chip wakes after an interrupt in about 3 to 5.5 mS (regardless of CPU speed), but WiFi was turned off to enter timed Light Sleep so you will need to re-initialize it if you are using WiFi.  Any timers (including OS_timers and PWM) will keep the chip from going into timed Light Sleep, and it will fall through to the next line in your code if timers are enabled.
 
 ### Test 6 - Forced Light Sleep, wake with GPIO interrupt
 
-Similar to Deep Sleep, but without the timer.  The chip sleeps at 0.4 mA amperage until it is woken by an external interrupt.  The only allowed interrupts are high level and low level; edge interrupts won't work.  If you have a design that needs to be woken frequently (more often than every 2 seconds) then you should consider using Forced Light Sleep.  For sleep periods longer than 2 seconds, Deep Sleep will be more energy efficient.  The chip wakes after an interrupt in about 3 to 5.5 mS (regardless of CPU speed), but WiFi was turned off to enter Forced Light Sleep so you will need to re-initialize it if you are using WiFi.  Any standard timers (including PWM) will keep the chip from going fully into Forced Light Sleep, and amperage will be ~ 2 mA with timers enabled.
+Similar to ESP.deepSleep(0).  The chip sleeps at 0.4 mA amperage until it is woken by an external interrupt.  The only allowed interrupts are high level and low level; edge interrupts won't work.  If you have a design that needs to be woken frequently (more often than every 2 seconds) then you should consider using Forced Light Sleep.  For sleep periods longer than 2 seconds, Deep Sleep will be more energy efficient.  The chip wakes after an interrupt in about 3 to 5.5 mS (regardless of CPU speed), but WiFi was turned off to enter Forced Light Sleep so you will need to re-initialize it if you are using WiFi.  Any standard timers (including PWM) will keep the chip from going fully into Forced Light Sleep, and amperage will be ~ 2 mA with timers enabled.
 
 ### Test 7 - Deep Sleep, wake with RF_DEFAULT
 
-In Deep Sleep almost everything is turned off, and the chip draws ~ 20 uA.  If you have D0/GPIO16 connected to RST, you can use the RTC timer to wake the chip up at a timed interval.  You can also wake it with an external RESET.  Waking with RF_DEFAULT means it will do an RFCAL if it needs to.  Doing **ESP.deepSleep(time)** without the mode variable uses this wake mode.  These first two Deep Sleep tests use the standard Deep Sleep function, so the WiFi connection is closed and the modem turned off, which takes up to 270 mS before Deep Sleep begins.  Deep Sleep ends with a RESET, and the boot time after that is ~ 130 mS.  Any Deep Sleep less than ~ 2 seconds is wasting energy due to the modem shut-off and boot times, and Forced Light Sleep will be a better choice as it recovers in ~ 5 mS from the previous program state.  The Deep Sleep tests will not go into Automatic Modem Sleep because delay() is not used.
+In Deep Sleep almost everything is turned off, and the chip draws ~ 20 uA.  If you have D0/GPIO16 connected to RST, you can use the RTC timer to wake the chip up at a timed interval.  You can also wake it solely with an external RESET with ESP.deepSleep(0, wake option) which disconnects the timer.  Waking with RF_DEFAULT means it will do an RFCAL if it needs to.  Doing **ESP.deepSleep(time)** without the mode variable uses this wake mode.  These first two Deep Sleep tests use the standard Deep Sleep function, so the WiFi connection is closed and the modem turned off, which takes up to 270 mS before Deep Sleep begins.  Deep Sleep ends with a RESET, and the boot time after that is ~ 130 mS.  Any Deep Sleep less than ~ 2 seconds is wasting energy due to the modem shut-off and boot times, and Forced Light Sleep will be a better choice as it recovers in ~ 5 mS from the previous program state.  The Deep Sleep tests will not go into Automatic Modem Sleep because delay() is not used.
 
-Note that a RESET during Deep Sleep (either external or from D0/GPIO16) does not clear the GPIO pins; some of them hold their previous state.  It's unknown how much else survives a reset, as it's not documented.
+Note that a RESET during Deep Sleep (either external or from D0/GPIO16) does not clear the GPIO pins; some of them hold their previous state.  It's unknown how much else survives a reset, as it's not well documented.
 
 ### Test 8 - Deep Sleep, wake with RFCAL