Standby Mode

Materials

  • AMB82-mini x 1

  • Optional: Push button x 1

  • Optional: Register 220 ohms x 1

  • Optional: USB to ttl serial cable x 1

Example

In this example, the development board will demo the non retention Standby Mode for power save. There are 6 wake-up sources. The system will count down 5s then go to Stand By mode. Upon the wake-up source being triggered, the system will be reboot and wake up again.

The module and board power consumption report under Standby mode are listed in these two tables below.

RTL8735B module power consumption test results

Wake-up source

Module power consumption

(uA)

Stand By Mode (measure at 3V3)

AON timer

41.22

AON GPIO

41.28

RTC

41.46

PON GPIO

41.07

UART/Serial1

41.32

Gtimer0

41.48

AMB82-MINI board Power Consumption

Wake-up source

Development board power consumption

Approximate measurement (mA) Voltage source : V_USB(5V)

Development board power consumption

Approximate measurement (mA) Voltage source : V_USB(3V)

Development board power consumption

Approximate measurement (mA) Voltage source : USB CH340(MicroUSB)

Development board power consumption

Approximate measurement (mA) Voltage source : USB OTG

Normal Mode

Standby Mode

Normal Mode

Standby Mode

Normal Mode

Standby Mode

Normal Mode

Standby Mode

AON timer

57.56

3.46

83.81

5.26

60.32

5.67

57.56

3.46

AON GPIO

57.56

3.46

83.81

5.26

60.32

5.67

57.56

3.46

RTC

57.56

3.46

83.81

5.26

60.32

5.67

57.56

3.46

PON GPIO

57.56

3.46

83.81

5.26

60.32

5.67

57.56

3.46

UART/Serial1

57.56

3.46

83.81

5.26

60.32

5.67

57.56

3.46

Gtimer0

57.56

3.46

83.81

5.26

60.32

5.67

57.56

3.46

Note

The USB‑UART bridge (CH340) and indicator LEDs (D1, D2, D3 with resistors R85, R101) were originally included to provide a better user experience. However, to achieve improved power consumption results, we eliminated these non‑essential current paths so that the measured values reflect only the SoC and essential circuitry.

Wake-up source

Development board power consumption

Approximate measurement after removing CH340 and LEDs (mA) Voltage source : V_USB(5V)

Development board power consumption

Approximate measurement after removing CH340 and LEDs (mA) Voltage source : V_USB(3V)

Development board power consumption

Approximate measurement after removing CH340 and LEDs (mA) Voltage source : USB CH340(MicroUSB)

Development board power consumption

Approximate measurement after removing CH340 and LEDs (mA) Voltage source : USB OTG

Normal Mode

Standby Mode

Normal Mode

Standby Mode

Normal Mode

Standby Mode

Normal Mode

Standby Mode

AON timer

54

0.28

81

1

54

0.2

54

0.2

AON GPIO

54

0.28

81

1

54

0.2

54

0.2

RTC

54

0.28

81

1

54

0.2

54

0.2

PON GPIO

54

0.28

81

1

54

0.2

54

0.2

UART/Serial1

54

0.28

81

1

54

0.2

54

0.2

Gtimer0

54

0.28

81

1

54

0.2

54

0.2

Open example in File -> Examples -> AmebaPowerMode -> StandbyMode

image01

Next is setting up the system and entering the power mode. Please refer to the following steps for entering Standby mode.

Use the USE_MULTIPLE_WAKEUP_SOURCES configuration flag to set for multiple or single wakeup sources.

0: single
1: multiple

Multiple Wake-up Sources

You can use bitwise OR to setup multiple wakeup sources for MULTI_WAKEUP_SOURCE

SLP_AON_TIMER (BIT0) - AON Timer wakeup
SLP_AON_GPIO (BIT1) - AON GPIO wakeup
SLP_RTC (BIT2) - RTC wakeup
SLP_PON_GPIO (BIT4) - PON GPIO wakeup
SLP_UART (BIT6) - UART wakeup
SLP_GTIMER (BIT7) - GTimer wakeup

For AON timer, please set CLOCK value to 0 or 1, 0:100kHz, 1:4MHz, SLEEP_DURATION unit is in seconds.

For AON GPIO, please set the AON_GPIO_PIN value to 21 or 22.

image02

For RTC, please set the value for ALARM_DAY, ALARM_HOUR, ALARM_MIN, or ALARM_SEC. All alarm values set the duration of RTC wake-up. The range is “1day, 0h, 0m, 0s” to “365day, 23h, 59min, 59s”.

For PON GPIO, please set the PON_GPIO_PIN to value between 0 and 11. The GPIO pin is set to active high, please refer to the following connection.

image03

For UART/Serial1, there is no setting required. However, USB to ttl serial cable Tx(green) and Rx(white) pin needs to connect to Serial1 Rx and Tx pin. Refer to the following connection. (Power 5V/3.3V Red, Ground Black)

image04

For GTimer, please set the value for GTIMER_DURATION, the timer sleep duration in seconds.

Single Wake-up Sources

Step 1. Ensure RETENTION is “#define RETENTION 0” in this example.
Step 2. Set up the “WAKEUP_SOURCE”, AON timer: 0; AON GPIO: 1; RTC: 2, PON GPIO: 3, UART/Serial1: 4, Gtimer0: 5.
Step 3. Set up the wake-up source setting. There are 6 wake-up sources, each one has its own settings.
For AON timer, at section “#if (WAKEUP_SOURCE == 0)”, set value to “CLOCK” and “SLEEP_DURATION”. “CLOCK” can be 4MHz or 100kHz. “SLEEP_DURATION” unit is in seconds.
For AON GPIO, at section “#elif (WAKEUP_SOURCE == 1)”, set value to “WAKUPE_SETTING”. “WAKUPE_SETTING” in this case is the Pin number, that can be 21 or 22. The GPIO pin is set to active high, please refer to the following connection.

image02

For RTC, at section “#elif (WAKEUP_SOURCE == 2)”, set value to “ALARM_DAY”, “ALARM_HOUR”, “ALARM_MIN”, or “ALARM_SEC”. All alarm values set the duration of RTC wake-up. The range is “1day, 0h, 0m, 0s” to “365day, 23h, 59min, 59s”.
For PON GPIO, at section “#elif (WAKEUP_SOURCE == 3)”, set value to “WAKUPE_SETTING”. “WAKUPE_SETTING” in this case is the Pin number, that can be 0 to 11. The GPIO pin is set to active high, please refer to the following connection.

image03

For UART/Serial1, there is no setting required. However, USB to ttl serial cable Tx(green) and Rx(white) pin needs to connect to Serial1 Rx and Tx pin. Refer to the following connection. (Power 5V/3.3V Red, Ground Black)

image04

For Gtimer0, at section “#elif (WAKEUP_SOURCE == 5)”, set value to “SLEEP_DURATION”. “SLEEP_DURATION” is the timer sleep duration in seconds.
Step 3. Start the Standby mode. There is only 1 optional setting for this step. When the wake-up source is set to RTC, use “PowerMode.start(1970, 1, 1, 0, 0, 0);” to replace “PowerMode.start();” for setting the start time. (Default is 1970.1.1 00:00:00).

image05

To wake up, all timers will automatically wake up when the duration is finished, all GPIO pins must active high by pressing the push button, UART needs to give input by Serial1 though USB-ttl cable.
The correct boot, enter Standby, and reboot cycle will be same as following picture.

image06