The SUPC bus clock (CLK_SUPC_APB) can be enabled and disabled in the Main Clock module.
A 32KHz clock, asynchronous to the user interface clock (CLK_SUPC_APB), is required to run BOD33 and BOD12 in sampled mode. Due to this asynchronicity, writing to certain registers will require synchronization between the clock domains. Refer to Synchronization for further details.