[Atria AT32A403A automotive MCU development board] + adjustable sine wave output with DAC

dmzdmz666666

[Atria AT32A403A automotive MCU development board] + adjustable sine wave output with DAC [Copy link]

Chapter 8: Using DAC to output adjustable sine wave

This article will evaluate the DAC output sine wave of AT32A403A.

The AT32A403A is equipped with a 12-bit DAC with a maximum update rate of 1MSPS and two channels. At the same time, the built-in output gain can be used to reduce the output impedance and directly drive the load without an external op amp.

When the output gain is not enabled, the output voltage range is larger, and the output is basically rail-to-rail. After enabling, the output is not rail-to-rail, and there is a rise of about 200mV.

-----------------------Start transplanting------------------------

The resources needed here include DAC.

First, create C files such as DAC.c and their corresponding h header files in the Hardware folder.

Select the PA4 output corresponding to DAC1, use software triggering, and do not enable cache. Do not use the DMA in the example, and the initialization is relatively simple.

Because we want to generate a sine wave here, we need to calculate the digital quantity required to output the sine wave. Here we use the sin() function directly to calculate. We need to add the <math.h> header file. The specific calculation formula is:

Where Sine_Dot_Num is the number of points contained in a waveform. The more points there are, the finer the waveform is, but the generated waveform frequency is lower because the update rate of the DAC is fixed.

It should be noted here that the DAC's sine wave data table must be generated first and then written to the output, because calculating and outputting at the same time may affect the update rate of each point of the DAC.

Finally, the analog value is output through the dac_1_data_set function

.

-----------------------practical testing------------------------

Try different output points: 50, 100, 200. After actual testing, 100 points basically works. Because the oscilloscope was suddenly damaged and could not be repaired during the Chinese New Year, I cannot take screenshots. I will take screenshots when I have the chance. (It has been broken twice, which is very uncomfortable)

The conclusion is that if this DAC is used to output a sine wave, the frequency should be limited to below 10KHz, otherwise it is basically unusable. Of course, the DAC built into the MCU is generally not used to generate medium and high frequency arbitrary waves. After all, it is not a high-speed DAC, but is used to generate static voltage.

At this point, the DAC output sine wave has been tested and is in a usable state.

littleshrimp

What kind of oscilloscope is so prone to breaking?

qwqwqw2088

Is the oscilloscope's key settings messed up? Try the reset button to do an automatic test. It's usually not easy to break.

dmzdmz666666

littleshrimp posted on 2024-2-13 09:02 What kind of oscilloscope is so prone to breaking?

Virtual Oscilloscope Dream Source

dmzdmz666666

qwqwqw2088 posted on 2024-2-13 09:56 Is the oscilloscope's button settings messed up? Try the reset button to automatically test it. It's usually not easy to break.

Virtual oscilloscopes are still not as reliable as desktop ones.

秦天qintian0303

littleshrimp posted on 2024-2-13 09:02 What kind of oscilloscope is so prone to breaking?

Be prepared to avoid pitfalls　　　　

秦天qintian0303

dmzdmz666666 posted on 2024-2-13 15:09 Virtual oscilloscopes are still not as reliable as desktop ones

But it has advantages in size and convenience.　　

dmzdmz666666

Qintianqintian0303 posted on 2024-2-14 23:26 However, it has advantages in size and convenience

If this is a general test requirement, a portable oscilloscope can do the job.

dmzdmz666666

Qintianqintian0303 posted on 2024-2-14 23:26 Prepare to avoid the pit

The main thing is that I tested it here before and it was broken. The manufacturer said it was not broken. I sent it back and then it broke again.