power_mode_switch_lpc#
Overview#
The power_mode_switch_lpc application shows the usage of normal power mode control APIs for entering the four kinds of low power mode: Sleep mode, Deep Sleep mode and Power Down mode, deep power down mode. When the application runs to each low power mode, the device would cut off the power for specific modules to save energy. The device can be also waken up by prepared wakeup source from external event.
Tips: This demo is to show how the various power mode can switch to each other. However, in actual low power use case, to save energy and reduce the consumption even more, many things can be done including:
Disable the clock for unnecessary module during low power mode. That means, programmer can disable the clocks before entering the low power mode and re-enable them after exiting the low power mode when necessary.
Disable the function for unnecessary part of a module when other part would keep working in low power mode. At the most time, more powerful function means more power consumption. For example, disable the digital function for the unnecessary pin mux, and so on.
Set the proper pin state (direction and logic level) according to the actual application hardware. Otherwise, the pin current would be activated unexpectedly waste some energy.
Other low power consideration based on the actual application hardware.
In order to meet typedef power consumption of DateSheet manual, Please configure MCU under the following conditions. • Configure all pins as GPIO with pull-up resistor disabled in the IOCON block. • Configure GPIO pins as outputs using the GPIO DIR register. • Write 1 to the GPIO CLR register to drive the outputs LOW. • All peripherals disabled.
Supported Boards#
LPC845BREAKOUT
Hardware requirements
Micro USB cable
LPC845 Breakout board
Personal Computer
Board settings
No special settings are required.
Prepare the demo
Connect a micro USB cable between the PC host and the CMSIS DAP USB port on the board.
Open a serial terminal with the following settings:
9600 baud rate
8 data bits
No parity
One stop bit
No flow control
Download the program to the target board.
Either press the reset button on your board or launch the debugger in your IDE to begin running the demo.
Running the demo
The log below shows example output of the power_mode_switch_lpc demo in the terminal window:
Power mode switch Demo for LPC8xx.
Select an option
1. Sleep mode
2. Deep Sleep mode
3. Power Down mode
4. Deep power down mode
/* after select power mode, terminal will output */
Select wakeup source
1. Wkt timer
2. K3, wakeup key
3. K2, reset key
/* after wakeup, terminal will output */
Wakeup.
LPCXpresso802
Functional description
This demo is to show how the various power mode can switch to each other. There is one known issue that terminal may receive mess code after enter deep power down mode, it is caused by the uart TX pin state changed by the MCU under deep power down mode. As the RM says, all the functional pins are tri-stated in deep power down mode except for the WAKEUP pin. So the state change will be captured by the virtual com port as mess code. Software has no workaround for the issue.
Hardware Requirements
Mini/micro USB cable
LPCXpresso802 board
Personal Computer
Board Settings
No special settings are required.
Run the Demo
Connect a micro USB cable between the PC host and the CMSIS DAP port(J4 on the board).
Open a serial terminal with the following settings:
9600 baud rate
8 data bits
No parity
One stop bit
No flow control
Choose an IDE, building the project and download the program to the target board. More information about how to compile and program the project can refer to the
[Getting Started with MCUXpresso SDK](../../../../docs/Getting Started with MCUXpresso SDK.pdf).
Launch the debugger in your IDE to begin running the demo.
Expected Result
Power mode switch Demo for LPC8xx.
Selecct an option
1. Sleep mode
2. Deep Sleep mode
3. Power Down mode
4. Deep power down mode
/* after select power mode, terminal will output */ Select wakeup source
1. PB3,wakeup key
2. Wkt timer
3. PB2, reset key
/* after wakeup, terminal will output */ Wakeup.
LPCXpresso804
Functional description
This demo is to show how the various power mode can switch to each other. There is one known issue that terminal may receive mess code after enter deep power down mode, it is caused by the uart TX pin state changed by the MCU under deep power down mode. As the RM says, all the functional pins are tri-stated in deep power down mode except for the WAKEUP pin. So the state change will be captured by the virtual com port as mess code. Software has no workaround for the issue. Note: The power consumption data for Sleep mode can reach 0.4mA. The power consumption data for Deep Sleep mode can reach 100uA. The power consumption data for Power Down mode can reach 9uA. If want to reach 6uA, please disable LPOsc. The power consumption data for Deep Power Down mode can reach 0.15uA.
Hardware Requirements
Mini/micro USB cable
LPCXpresso804 board
Personal Computer
Board Settings
No special settings are required.
Run the Demo
Connect a micro USB cable between the PC host and the CMSIS DAP port(J4 on the board).
Open a serial terminal with the following settings:
9600 baud rate
8 data bits
No parity
One stop bit
No flow control
Choose an IDE, building the project and download the program to the target board. More information about how to compile and program the project can refer to the
[Getting Started with MCUXpresso SDK](../../../../docs/Getting Started with MCUXpresso SDK.pdf).
Launch the debugger in your IDE to begin running the demo.
Expected Result
Power mode switch Demo for LPC8xx.
Selecct an option
1. Sleep mode
2. Deep Sleep mode
3. Power Down mode
4. Deep power down mode
/* after select power mode, terminal will output */ Select wakeup source
1. S1,wakeup key
2. Wkt timer
3. S3, reset key
/* after wakeup, terminal will output */ Wakeup.
LPCXpresso824MAX
Functional description
This demo is to show how the various power mode can switch to each other.
Hardware Requirements
Mini/micro USB cable
LPCXpresso824MAX board
Personal Computer
Board Settings
No special settings are required.
Run the Demo
Connect a micro USB cable between the PC host and the CMSIS DAP port(J4 on the board).
Open a serial terminal with the following settings:
9600 baud rate
8 data bits
No parity
One stop bit
No flow control
Choose an IDE, building the project and download the program to the target board. More information about how to compile and program the project can refer to the
[Getting Started with MCUXpresso SDK](../../../../docs/Getting Started with MCUXpresso SDK.pdf).
Launch the debugger in your IDE to begin running the demo.
Expected Result
Power mode switch Demo for LPC8xx.
Selecct an option
1. Sleep mode
2. Deep Sleep mode
3. Power Down mode
4. Deep power down mode
/* after select power mode, terminal will output */ Select wakeup source
1. Wkt timer
2. SW1, wakeup key
3. SW3, reset key
/* after wakeup, terminal will output */ Wakeup.
LPCXpresso845MAX
Functional description
This demo is to show how the various power mode can switch to each other. There is one known issue that terminal may receive mess code after enter deep power down mode, it is caused by the uart TX pin state changed by the MCU under deep power down mode. As the RM says, all the functional pins are tri-stated in deep power down mode except for the WAKEUP pin and the RESET pin. So the state change will be captured by the virtual com port as mess code. Software has no workaround for the issue.
Hardware Requirements
Mini/micro USB cable
LPCXpresso845MAX board
Personal Computer
Board Settings
No special settings are required.
Run the Demo
Connect a micro USB cable between the PC host and the CMSIS DAP port(J4 on the board).
Open a serial terminal with the following settings:
9600 baud rate
8 data bits
No parity
One stop bit
No flow control
Choose an IDE, building the project and download the program to the target board. More information about how to compile and program the project can refer to the
[Getting Started with MCUXpresso SDK](../../../../docs/Getting Started with MCUXpresso SDK.pdf).
Launch the debugger in your IDE to begin running the demo.
Expected Result
Power mode switch Demo for LPC8xx.
Selecct an option
1. Sleep mode
2. Deep Sleep mode
3. Power Down mode
4. Deep power down mode
/* after select power mode, terminal will output */ Select wakeup source
1. Wkt timer
2. SW2, wakeup key
3. SW3, reset key
/* after wakeup, terminal will output */ Wakeup.
LPCXpresso860MAX
Hardware requirements
Micro USB cable
LPCXpresso860MAX board
Personal Computer
Board settings
Prepare the Demo
Connect a micro USB cable between the PC host and the CMSIS DAP USB port (J4) on the board
Open a serial terminal with the following settings (See Appendix A in Getting started guide for description how to determine serial port number):
9600 baud rate
8 data bits
No parity
One stop bit
No flow control
Download the program to the target board.
Either press the reset button on your board or launch the debugger in your IDE to begin running the demo.
Running the demo
Expected Result
Power mode switch Demo for LPC8xx.
Selecct an option
1. Sleep mode
2. Deep Sleep mode
3. Power Down mode
4. Deep power down mode
/* after select power mode, terminal will output */ Select wakeup source
1. Wkt timer
2. SW2, wakeup key
3. SW3, reset key
/* after wakeup, terminal will output */ Wakeup.