lpc_dac_dma#
Overview#
The dac_dma example shows how to use DAC with dma and produce an arbitrary, user-defined waveform of selectable frequency.The output can be observed with an oscilloscope.
When the DAC’s double-buffer feature is enabled, any write to the CR register will only load the pre-buffer, which shares its register address with the CR register. The CR itself will be loaded from the pre-buffer whenever the counter reaches zero and the DMA request would be raised. At the same time the counter is reloaded with the COUNTVAL register value. user-defined waveform array would be transfered to pre-buffer in order by DMA.
Supported Boards#
LPC845BREAKOUT
Hardware requirements
Micro USB cable
LPC845 Breakout board
Personal Computer
Board settings
PIO0_17 is DAC0 output pin.
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 the output of the DAC dma driver demo in the terminal window:
DAC dma Example.
Please probe the signal using an oscilloscope.
Probe the signal of PIO0_17 using an oscilloscope.
LPCXpresso845MAX
Toolchain supported
IAR embedded Workbench 8.11.3
Keil MDK 5.23
MCUXpresso10.1.0
Hardware requirements
Micro USB cable
LPCXpresso54608 board
Personal Computer
Board settings
J6-5 is DAC0 output pin.
Prepare the Demo
Connect a micro USB cable between the host PC and the LPC-Link USB port (J8) on the target 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 the output of the hello world demo in the terminal window:
DAC dma Example.
Please probe the signal using an oscilloscope.