usart_dma_low_power#
Overview#
The usart_dma_low_power example shows how to use usart to wake up the system in low power modes, and how to wake up for DMA only. In this example, one usart instance connects to PC through usart, the board will start receiving characters from PC and then go into low power mode. Each character from PC will only wake up the DMA but the CPU keeps in low power mode. Once 8 characters were received, system will be woken up and echo the characters to PC.
Supported Boards#
EVK-MIMXRT595
Hardware requirements
Micro USB cable
EVK-MIMXRT595 board
Personal Computer
Board settings
Prepare the Demo
Connect a micro USB cable between the PC host and the CMSIS DAP USB port (J40) 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.
Launch the debugger in your IDE to begin running the demo.
Running the demo
When the demo runs successfully, the log would be seen on the terminal as follows (Note: please don’t input more than 16 bytes once as it might lead to UART FIFO overflow and result in failure):
USART DMA low power example
Send back received data
###### Echo every 8 characters (1st char 'q' leads to end).
Input any key to start.
Now enter deep sleep and wait for 8 characters.
###### 12345678
Input any key to start.
Now enter deep sleep and wait for 8 characters.
###### asdfghjk
Input any key to start.
Now enter deep sleep and wait for 8 characters.
qwertyui
Done!
EVK-MIMXRT685
Hardware requirements
Micro USB cable
EVK-MIMXRT685 board
Personal Computer
Board settings
Prepare the Demo
Connect a micro USB cable between the PC host and the CMSIS DAP USB port (J5) 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.
Launch the debugger in your IDE to begin running the demo.
Running the demo
When the demo runs successfully, the starting logs of the USART dma low power example should be displayed like:
USART DMA low power example
Send back received data
###### Echo every 8 characters (1st char 'q' leads to end).
Input any key to start.
Then after sending one random character, the following log on the terminal should be like:
Now enter deep sleep and wait for 8 characters.
qwer1234
Done!
MIMXRT685-AUD-EVK
Hardware requirements
Micro USB cable
MIMXRT685-AUD-EVK board
Personal Computer
Board settings
Prepare the Demo
Connect a micro USB cable between the PC host and the CMSIS DAP USB port (J5) 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.
Launch the debugger in your IDE to begin running the demo.
Running the demo
When the demo runs successfully, the starting logs of the USART dma low power example should be displayed like:
USART DMA low power example
Send back received data
###### Echo every 8 characters (1st char 'q' leads to end).
Input any key to start.
Then after sending one random character, the following log on the terminal should be like:
Now enter deep sleep and wait for 8 characters.
qwer1234
Done!