Hello!
I've been using STM32 uC for a long time, and I decided to try the STM32H503RBT6 microcontroller.
Using the NUCLEO-H503RB I created a brand new project and set up the DAC (without any timers or DMA, just plain simple direct DAC) and nothing else - (config in the picture below).
Using a scope, I noticed a lot of glitches on the generated waveform (a simple 10 steps waveform from 0V to 3.3V). Sometimes it worked as it should, sometimes it didn't work at all, sometimes it worked but the waveform was super random (Oh! And it even changed this behavior if I simply reset the board). I tried to change a lot of settings (except in the clock config tab), but nothing made it work 100% of the time. Only then I decided to try changing the clock settings.
After a day of frustrating debugging, I noticed that the interface of cubeMX seems to be wrong. I checked a hundred times if I chose the correct microcontroller when making the project, etc, but it was configured correctly.
In the picture below, is the configuration that CubeMX shows me when choosing the clock source and the maximum speed allowed to the DAC. It allows me to choose between 6 clock sources and tells me the frequency should be less or equal to 125 MHz when using HCLK.
However, according to the datasheet, both settings (6 clock choices and <= 125 MHz) are incorrect:
When I created the project, the HCLK option was already selected. However, the "clock speed" box was red, saying I couldn't use anything more then 125 MHz. And that's where the problems started, since I had to change the clock source because I didn't want to lower my HCLK to 125 MHz. And changing the clock source to others not stated in the datasheet caused a lot of problems.
After a day of debugging, I decided to use the HCL clock and ignore the "wrong clock speed warning". Everything worked as it should and flawlessly. However, every time that I generate a new CubeMX code, it warns me that there are errors, and it can cause a LOT of confusion for my future-self or others that open this project.
Therefore, my question is: is CubeMX incorrect or am I missing something ?
CubeIDE version used: 1.15.1 (downloaded 2 days ago)
Board Used: NUCLEO-H503RB
Thanks
Hello @Omgareyouokaydood
ADC and DAC are sharing same clock source. In case both are used, the clock can't be higher than the Maximum allowed clock frequency for the ADC as shown on the Table 17:
But, if we use only the DAC, User must still be able to select a clock higher than the ADC limit clock. This is a known issue on the CubeMX that has been already reported on the internal ticket 179875 for correction on the coming version of the STM32CubeMX (coming soon).
Best Regards.
STTwo-32
