Question about Clock enable

[Uwe Bonnes]

Posted on November 03, 2014 at 18:32

Hello,

let us assume I want to put all pins of GPIOA into pull-up, but don't need GPIOA later. After enabling RCC_AHB1ENR_GPIOAEN and setting the mode in GPIOA can I safely disable RCC_AHB1ENR_GPIOAEN again without affecting the status set to GPIOA? Does the same hold e.g. for SYSCFG when some Interrupt remap is needed? Can the SYSCFG clock be disabled after doing the remap? #rcc #disabling-device-clocks

[Tesla DeLorean]

Posted on November 03, 2014 at 18:46

I don't think ST provides any gate level breakdown of the design, removing the clock from the synchronous logic will leave it's latches and flip-flops in the last clocked state, combinatorial logic attached to those registers will behave as before, but don' expect internal states to change, or to be able to access the peripheral.

Brief experiments should be able to tell you if the functionality you desire is expressed by the logic.