2017-02-09 07:34 PM
I am using the STM32 ADC to caputure outer voltage , while the requirement to ADC accuracy is not very high. So I decided to use the VDDA as the reference voltage. BUT the actually vdd added to the mcu exist deviation from each others. Is there any way to get the acutal vdda after reset.?
2017-02-09 08:40 PM
Most STM32 parts also provide a VREFINT which is an internal 1.25V reference you can sample and use to compute the VREF+/VDDA voltages.
2017-02-10 01:32 AM
Thanks for your replay.
I still have questions about how to get the VRETINT_CAL mentioned in the datasheet.
thanks
2017-02-10 07:15 AM
What STM32 specifically are you using they make hundreds of parts in dozen of families, it's like saying you drive a Ford.
The Reference Manual should provide the ROM/OTP address of the memory location holding the VREFINT_CAL value.
I'd start by assuming the voltage is 1.25V, and scaling back up to what a 4095 value would represent based on the reading for VREFINT, and see how close that is to the voltage you can measure with a volt-meter.