HIBERNATE (SystemSleepMode)

sleep() [ Sleep ]

// EXAMPLE
SystemSleepConfiguration config;
config.mode(SystemSleepMode::HIBERNATE)
      .gpio(WKP, RISING);
System.sleep(config);

The SystemSleepMode::HIBERNATE mode is the similar to the classic SLEEP_MODE_DEEP. It is the lowest power mode, however there are limited ways you can wake:

Wake Mode	Gen 2	Gen 3	Gen 4
GPIO	WKP RISING Only	✓	WKP
Time (RTC)	✓	¹	✓
Analog		✓

¹Tracker SoM can wake from RTC in HIBERNATE mode. Other Gen 3 devices cannot.

Typical power consumption in hibernate sleep mode, based on the wakeup source:

Device	GPIO	RTC
P2	114 uA	115 uA
M404	44 uA	43 uA
M524	26 uA	27 uA
T523 Eval	103 uA	95 uA
T402 Eval	103 uA	95 uA
Boron 2G/3G	146 uA	n/a
Boron LTE	106 uA	n/a
B402 SoM	26 uA	n/a
B523 SoM	30 uA	n/a
Argon	65 uA	n/a
Electron	114 uA	114 uA
Photon	114 uA	114 uA

In this mode on wake, device is reset, running setup() again.

Gen 3 Devices (nRF52) (B-Series SoM, Tracker SoM, Tracker One, Boron, Argon, and E404X):

On the Argon, Boron, B-Series SoM, and E404X you can only wake by pin, not by time, in HIBERNATE mode.
On the Tracker SoM, Tracker One, and Monitor One, you can wake by time from HIBERNATE mode using the hardware RTC (AM1805).
You can wake from HIBERNATE (SLEEP_MODE_DEEP) on any GPIO pin, on RISING, FALLING, or CHANGE, not just WKP/D8 with Device OS 2.0.0 and later on Gen 3 devices.
Since the difference in current consumption is so small between HIBERNATE and ULTRA_LOW_POWER, using ULTRA_LOW_POWER is a good alternative if you wish to wake based on time on Gen 3 devices. The difference is 106 uA vs. 127 uA on the Boron LTE, for example.
GPIO are kept on; OUTPUT pins retain their HIGH or LOW voltage level during sleep.
On Gen 3 devices the RTC does not run in HIBERNATE sleep and clock time and date will not be valid until the next cloud connection.
Gen 3 devices (Argon, Boron, B-Series SoM, E404X, Tracker SoM, Tracker One), can wake on analog voltage comparison.

P2 Devices (RTL872x):

The P2 does not support holding a GPIO in OUTPUT mode when in HIBERNATE mode. The pin will go into high impedance mode.
The P2 can only wake from HIBERNATE mode on the pins listed below with the note "Pin can wake from HIBERNATE sleep," RISING, FALLING, or CHANGE.
On the P2, when waking from HIBERNATE the RTC will be reset and clock time and date will not be valid until the next cloud connection.
The P2 does not support wake on analog, BLE, or UART serial.

These P2 pins can wake from HIBERNATE sleep mode:

Pin	Pin Name	Description	Interface	MCU
30	D10 / WKP	D10 GPIO, Serial 3 CTS, WKP. (Was WKP/A7 on P1.)	Pin can wake from HIBERNATE sleep	PA[15]
40	S0 / D15	S0 GPIO, PWM, SPI MOSI, Serial3 TX, I2S MCLK. (Was P1S0 on P1.)	Pin can wake from HIBERNATE sleep	PA[12]
41	S1 / D16	S1 GPIO, PWM, SPI MISO, Serial3 RX. (Was P1S1 on P1.)	Pin can wake from HIBERNATE sleep	PA[13]
42	S2 / D17	S2 GPIO, SPI SCK, Serial3 RTS. (Was P1S2 on P1.)	Pin can wake from HIBERNATE sleep	PA[14]
45	D2	D2 GPIO, Serial2 RTS, SPI1 MOSI	Pin can wake from HIBERNATE sleep	PA[16]
51	D3	D3 GPIO, Serial2 CTS, SPI1 MISO	Pin can wake from HIBERNATE sleep	PA[17]
52	D4	D4 GPIO, Serial2 TX, SPI1 SCK	Pin can wake from HIBERNATE sleep	PA[18]
53	D5	D5 GPIO, Serial2 RX, SPI1 SS	Pin can wake from HIBERNATE sleep	PA[19]

On the P2, pins S4, S5, and S6 do not support pull-up or pull-down in HIBERNATE sleep mode. Use an external pull resistor if this is required. These also cannot be used as wake from hibernate sleep mode.

Pin	Pin Name	Description	Interface	MCU
33	S6 / D21	S6 GPIO, I2S WS. (Was P1S6/TESTMODE on P1.)	No internal pull up or pull down in HIBERNATE sleep mode.	PB[31]
47	S4 / D19	S4 GPIO, I2S RX. (Was P1S4 on P1.)	No internal pull up or pull down in HIBERNATE sleep mode.	PA[0]

Photon 2 Devices (RTL872x):

The Photon 2es do not support holding a GPIO in OUTPUT mode when in HIBERNATE mode. The pin will go into high impedance mode.
The Photon 2 can only wake from HIBERNATE on the pins listed below with the note "Pin can wake from HIBERNATE sleep," RISING, FALLING, or CHANGE.
On the Photon 2, pin D10 is in the same position as the Argon/Feather pin D8.

On the Photon 2, when waking from HIBERNATE the RTC will be reset and clock time and date will not be valid until the next cloud connection.
The Photon 2 does not support wake on analog, BLE, or UART serial.

Pin Name	Description	Interface	MCU
D2	D2 GPIO, Serial2 RTS, SPI1 MOSI	Pin can wake from HIBERNATE sleep	PA[16]
D3	D3 GPIO, Serial2 CTS, SPI1 MISO	Pin can wake from HIBERNATE sleep	PA[17]
D4	D4 GPIO, Serial2 TX, SPI1 SCK	Pin can wake from HIBERNATE sleep	PA[18]
D5	D5 GPIO, Serial2 RX, SPI1 SS	Pin can wake from HIBERNATE sleep	PA[19]
D10 / WKP	D10 GPIO. Serial3 CTS, WKP. Was D8/WKP on Gen 3.	Pin can wake from HIBERNATE sleep	PA[15]
MISO / D16	D16 GPIO, S1 GPIO, PWM, SPI MISO, Serial3 RX.	Pin can wake from HIBERNATE sleep	PA[13]
MOSI / D15	D15 GPIO, S0 GPIO, PWM, SPI MOSI, Serial3 TX	Pin can wake from HIBERNATE sleep	PA[12]
SCK / D17	SPI SCK, D13 GPIO, S3 GPIO, Serial3 RTS	Pin can wake from HIBERNATE sleep	PA[14]

On the Photon 2, pin S4 is in the position of A4 on the Argon and other Feather devices. It does not support pull-up or pull-down in HIBERNATE sleep mode. Use an external pull resistor if this is required. These pins also cannot be used to wake from hibernate sleep mode.

Pin Name	Description	Interface	MCU
S4 / D19	S4 GPIO, Was A4 on Gen 3.	No internal pull up or pull down in HIBERNATE sleep mode.	PA[0]

M-SoM Devices (RTL872x):

The M-SoM does not support holding a GPIO in OUTPUT mode when in HIBERNATE mode. The pin will go into high impedance mode.
The M-SoM can only wake from HIBERNATE mode on the pins listed below with the note "Pin can wake from HIBERNATE sleep," RISING, FALLING, or CHANGE.

On the M-SoM, when waking from HIBERNATE the RTC will be reset and clock time and date will not be valid until the next cloud connection.
The M-SoM does not support wake on analog, BLE, or UART serial.

Pin	Pin Name	Description	Interface	MCU
36	TX / D9	Serial TX, PWM, GPIO, SPI1 MOSI, I2S MCLK	Pin can wake from HIBERNATE sleep	PA[12]
38	RX / D10	Serial RX, PWM, GPIO, SPI1 MISO	Pin can wake from HIBERNATE sleep	PA[13]
40	D3	D3 GPIO, Serial1 CTS flow control (optional), SPI1 SS	Pin can wake from HIBERNATE sleep	PA[15]
42	D2	D2 GPIO, Serial RTS flow control (optional), SPI1 SCK	Pin can wake from HIBERNATE sleep	PA[14]
47	A7 / WKP	A7 Analog In, WKP, GPIO D28	Pin can wake from HIBERNATE sleep	PA[20]
48	D8	D8 GPIO, SPI SS	Pin can wake from HIBERNATE sleep	PA[19]
50	MISO / D11	D11 GPIO, PWM, SPI MISO	Pin can wake from HIBERNATE sleep	PA[17]
52	MOSI / D12	D12 GPIO, PWM, SPI MOSI	Pin can wake from HIBERNATE sleep	PA[16]
54	SCK / D13	D13 GPIO, SPI SCK	Pin can wake from HIBERNATE sleep	PA[18]

Most pins can use INPUT_PULLUP or INPUT_PULLDOWN in sleep modes. The exception is HIBERNATE sleep mode where

Pin D21 can only use an external hardware pull-up or pull down in HIBERNATE sleep mode. It also cannot be used to wake from hibernate sleep mode.

Pin	Pin Name	Description	Interface	MCU
17	D21	D21 GPIO, I2S RX	No internal pull up or pull down in HIBERNATE sleep mode.	PA[0]

Gen 2 Devices (STM32) (E-Series, Electron, Photon, and P2; does not include E404X):

On the Photon, P1, Electron, and E-Series you can only wake on time or WKP RISING in HIBERNATE mode.
GPIO are put into high impedance state before sleep. However, you can use pinMode(INPUT) to disconnect output pins on Gen 2 devices so the same code can be used for both Gen 2 and Gen 3 with HIBERNATE mode.

Cellular Devices (B-Series SoM, Tracker SoM, Tracker One, Boron, E404X, E-Series, and Electron):

On cellular devices, the cellular modem is turned off in HIBERNATE mode. This reduces current consumption but increases the time to reconnect. Also, you should avoid any HIBERNATE period of less than 10 minutes on cellular devices. Since the cellular modem needs to reconnect to the cellular network on wake, your mobile carrier may ban your SIM card from the network for aggressive reconnection if you reconnect more than approximately 6 times per hour.