View STM32 MCU peripheral registers
In Debug Perspective ("Debug" button - right side of the top tool bar) there is the area occupying the top right side of the SW. You can choose from among some tabs, such as "Variables" and "Breakpoints". One of the tabs is "I/O Registers" - in this tab you have the list of the CPU peripherals. Expand one, and you will see its registers. Then you have to double-click on a register icon to enable reading its value from the CPU (it will update automaticaly with each break or step). Double-click again on the register to disable reading.