usart_dma_rb_transfer#
Overview#
The usart dma ring buffer example shows how to use usart driver with DMA driver used:
In this example, a ring buffer was implemented to receive the characters from PC side, to implemente the ring buffer, a descriptor was created and chain itself as the next descriptor, then the DMA transfer will start a continuous transfer.
While data in the ring buffer reach 8 characters, routine will send them out using DMA mode.
Supported Boards#
LPCXpresso51U68
Hardware requirements
Micro USB cable
LPCXpresso51U68 board
Personal Computer
Board settings
No special is needed.
Prepare the Demo
Connect a micro USB cable between the PC host and the CMSIS DAP USB port (J6) 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):
115200 baud rate
8 data bits
No parity
One stop bit
No flow control
Download the program to the target board.
Reset the SoC and run the project.
Running the demo
When the demo runs successfully, the log would be seen on the CMSIS DAP terminal like:
USART DMA ring buffer example
Board will send back received data
LPCXpresso54628
Hardware requirements
Micro USB cable
LPCXpresso54628 board
Personal Computer
Board settings
No special is needed.
Prepare the Demo
Connect a micro USB cable between the PC host and the LPC-Link USB port (J8) on the board.
Open a serial terminal with the following settings:
115200 baud rate
8 data bits
No parity
One stop bit
No flow control
Download the program to the target board.
Reset the SoC and run the project.
Running the demo
When the demo runs successfully, the log would be seen on the terminal like:
USART DMA ring buffer example
Board will send back received data
LPCXpresso54S018
Hardware requirements
Micro USB cable
LPCXpresso54S018 board
Personal Computer
Board settings
No special is needed.
Prepare the Demo
Connect a micro USB cable between the PC host and the LPC-Link USB port (J8) on the board.
Open a serial terminal with the following settings:
115200 baud rate
8 data bits
No parity
One stop bit
No flow control
Download the program to the target board.
Reset the SoC and run the project.
Running the demo
This demo is an external flash plain load demo, ROM will copy image in external flash to SRAMX to run:
Build the demo to generate a bin file. Note: If need to generate bin file using MCUXpresso IDE, below steps need to be followed: Set in example Properties->C/C++ Build->Settings->Build steps->Post-build steps->Edit enbable arm-none-eabi-objcopy -v -O binary “&{BuildArtifactFileName}” “&{BuildArtifactFileBaseName}.bin”
This plainload example linked the vector table to 0x00000000, but program to external flash 0x10000000.
Program the bin file to external on board flash via SEGGER J-FLASH Lite(V6.22 or higher):
a. Open SEGGER J-FLASH Lite, select device LPC54S018.
b. Click the ‘Erase Chip’ to erase the extrenal flash.(if can not success, press SW4 button and reset the board, and try to erase again)
c. Select the bin data file, set the ‘.bin/Erase Start’ address to 0x10000000, then click ‘Program Device’ Note: Please use above way to program the binary file built by armgcc tool chain to external flash. For IAR, KEIL, MCUXpresso IDE, you can use the IDE tool to program the external flash.
When the demo runs successfully, the log would be seen on the terminal like:
USART DMA ring buffer example
Board will send back received data
LPCXpresso54S018M
Hardware requirements
Micro USB cable
LPCXpresso54S018M board
Personal Computer
Board settings
No special is needed.
Prepare the Demo
Connect a micro USB cable between the PC host and the LPC-Link USB port (J8) on the board.
Open a serial terminal with the following settings:
115200 baud rate
8 data bits
No parity
One stop bit
No flow control
Download the program to the target board.
Reset the SoC and run the project.
Running the demo
This demo is an external flash plain load demo, ROM will copy image in external flash to SRAMX to run:
Build the demo to generate a bin file. Note: If need to generate bin file using MCUXpresso IDE, below steps need to be followed: Set in example Properties->C/C++ Build->Settings->Build steps->Post-build steps->Edit enbable arm-none-eabi-objcopy -v -O binary “&{BuildArtifactFileName}” “&{BuildArtifactFileBaseName}.bin”
This plainload example linked the vector table to 0x00000000, but program to external flash 0x10000000.
Program the bin file to external on board flash via SEGGER J-FLASH Lite(V6.22 or higher):
a. Open SEGGER J-FLASH Lite, select device LPC54S018M.
b. Click the ‘Erase Chip’ to erase the extrenal flash.(if can not success, press SW4 button and reset the board, and try to erase again)
c. Select the bin data file, set the ‘.bin/Erase Start’ address to 0x10000000, then click ‘Program Device’ Note: Please use above way to program the binary file built by armgcc tool chain to external flash. For IAR, KEIL, MCUXpresso IDE, you can use the IDE tool to program the external flash.
When the demo runs successfully, the log would be seen on the terminal like:
USART DMA ring buffer example
Board will send back received data