Clock tree
When the above chart, this is the clock tree, you can clearly see that each branch of the clock is how to go, how to configure, look at the map, you can follow the order from right to left to see, which is to find the function you want to configure, then look at how the function of the clock turned on, for example, the screenshot RTC clock RTC section.
As can be seen, the system clock source has four, as in the screenshot below, wherein 1 and 4 are inside the chip, the crystal oscillator 2 and 3 are external to the chip.
After the clock source frequency division or multiplication, 108MHz finally obtained (FIG. 1) to the AHB use, are hung below the APB1 AHB (FIG. 2) and APB2 and (FIG. 3), most peripherals are hanging the two bridges, with the exception of course (FIGS. 4 and 5)
