## LPTIM1EN / LPTIMER1EN
Only stm32f413 has LPTIM1 peripheral, ref manual bit names:
LPTIMER1EN, LPTIMER1RST, LPTIMER1LPEN, LPTIMER1SEL
action: Rename to LPTIM1(EN|RST|...) for consistency (matches peripheral name)
## FMC / FSMC
not available as peripheral in the YAML anyway.. TODO: why?
EN and RST
FSMC: f405, f407, f412, f413
FSC: f427, f429, f446, f469
action: none
## CECEN / CAN3EN
mutually exclusive peripherals, alias ok?
CECEN: f446
CAN3EN: f413
action: split off f4x3 yaml, f423 exists, but not available as svd
## USART / UART
all over the place, register names in ref manual not always consistent
stm32 follows a simple rule for the actual peripherals:
USART 1-3, 6
UART 4, 5, 7-10
action: rename enable/rst bits to rules above
Register block based in STM32F427ZI and STM32L4R9.
Use bool for reset registers.
Define clock mapping for RNG peripherals. There are no 1 <-> 1 mapping
of RNG peripheral to clock in the Cubedb sources. The mapping will
pre-select the clock source for RNG for now.
