problems with Blue Pill (stm32f103c8t6) direct register manipulation I'm trying to access registers but I keep getting the &quot;was not declared in this scope&quot; error message.
I'm currently using the STM32F1xx boards from http://dan.drown.org/stm32duino/package_STM32duino_index.json
The board package does not seam to recognize any of the registers from the reference manual, mostly trying to access the ADC registers such as 'ADC_CR2'. Does anyone know where I can find the register names which works in the Arduino IDE?
you need to use something like this:
ADC1-&gt;CR2 = ... ;

note 2 things:

you need to use ADC1, ADC2 ... to access the registers. not just ADC.
you need to use arrow (-&gt;) operator to access the registers

and you may need to include the header file, something like this :
#include &lt;stm32f030x6.h&gt;

find the proper header file for your MCU. (it's not the same as stm32f1xx, but if proper definitions are made somewhere, it may also work)