2024-06-24 12:59 AM
Hello,
I'm a bit confused to how use the VREFBUF on this MCU.
I want to use the internal voltage reference (SCALE 0 : 2.5V) for better ADC accuracy.
Do I have to connect the VREF+ pin (20) to AVDD (+3.3V) or I've to connect it to a 1uF + 100nF capacitors only?
2024-06-24 02:48 AM
Connect it to a 1uF + 100nF capacitors only.
JW
2024-06-24 07:42 AM
Okay, and apart of the CubeMX config (VREFBUF = Internal Voltage Reference with SCALE 0), does the ADC automatically choose that VREFINT reference voltage without any supplemental software/register manipulation in my C code?
Thanks
2024-06-24 08:21 AM
There is no change from ADC point of view.
ADC's reference is always the VREF+ pin.
Here, you are connecting an internal source to VREF+ pin.
JW
2024-06-24 09:22 AM - edited 2024-06-24 09:24 AM
So that VREFINT voltage is set to 2.5V with SCALE0, connected to the pin 20, filtered by the 1uF+100nF external caps connected to this pin, and then the ADC uses that VREFINT for its reference.
I'm correct?
2024-06-24 10:12 AM - edited 2024-06-24 10:13 AM
I don't know what's pin 20 as I am not going to look up your STM32's DS; but if it's VREF+ then yes.
If in doubts, getting a cheap Nucleo board to test any of the hardware features may be a good idea.
JW
2024-06-24 11:30 AM
Pin 20 is indeed VREF+ on the STM32H750VBT6.
I've to try this.
Thanks for your answers :)